Publications 2007

Nosten F, White NJ. 2007. Artemisinin-based combination treatment of falciparum malaria. Am J Trop Med Hyg, 77 (6 Suppl), pp. 181-192. | Citations: 334 (Scopus) | Show Abstract | Read more

Artemisinin-based combination treatments (ACTs) are now generally accepted as the best treatments for uncomplicated falciparum malaria. They are rapidly and reliably effective. Efficacy is determined by the drug partnering the artemisinin derivative and, for artesunate-mefloquine, artemether-lumefantrine, and dihydroartemisinin-piperaquine, this usually exceeds 95%. Artesunate-sulfadoxine-pyrimethamine and artesunate-amodiaquine are effective in some areas, but in other areas resistance to the partner precludes their use. There is still uncertainty over the safety of artemisinin derivatives in the first trimester of pregnancy, when they should not be used unless there are no effective alternatives. Otherwise, except for occasional hypersensitivity reactions, the artemisinin derivatives are safe and remarkably well tolerated. The adverse effect profiles of the artemisinin-based combination treatments are determined by the partner drug. Most malaria endemic countries have now adopted artemisinin-based combination treatments as first-line treatment of falciparum malaria, but in most of these only a minority of the patients that need artemisinin-based combination treatments actually receive them.

Chau TT, Campbell JI, Galindo CM, Van Minh Hoang N, Diep TS, Nga TTT, Van Vinh Chau N, Tuan PQ, Page AL, Ochiai RL et al. 2007. Antimicrobial drug resistance of Salmonella enterica serovar typhi in asia and molecular mechanism of reduced susceptibility to the fluoroquinolones. Antimicrob Agents Chemother, 51 (12), pp. 4315-4323. | Citations: 144 (Scopus) | Show Abstract | Read more

This study describes the pattern and extent of drug resistance in 1,774 strains of Salmonella enterica serovar Typhi isolated across Asia between 1993 and 2005 and characterizes the molecular mechanisms underlying the reduced susceptibilities to fluoroquinolones of these strains. For 1,393 serovar Typhi strains collected in southern Vietnam, the proportion of multidrug resistance has remained high since 1993 (50% in 2004) and there was a dramatic increase in nalidixic acid resistance between 1993 (4%) and 2005 (97%). In a cross-sectional sample of 381 serovar Typhi strains from 8 Asian countries, Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, and central Vietnam, collected in 2002 to 2004, various rates of multidrug resistance (16 to 37%) and nalidixic acid resistance (5 to 51%) were found. The eight Asian countries involved in this study are home to approximately 80% of the world's typhoid fever cases. These results document the scale of drug resistance across Asia. The Ser83-->Phe substitution in GyrA was the predominant alteration in serovar Typhi strains from Vietnam (117/127 isolates; 92.1%). No mutations in gyrB, parC, or parE were detected in 55 of these strains. In vitro time-kill experiments showed a reduction in the efficacy of ofloxacin against strains harboring a single-amino-acid substitution at codon 83 or 87 of GyrA; this effect was more marked against a strain with a double substitution. The 8-methoxy fluoroquinolone gatifloxacin showed rapid killing of serovar Typhi harboring both the single- and double-amino-acid substitutions.

Day N, Dondorp AM. 2007. The management of patients with severe malaria. Am J Trop Med Hyg, 77 (6 Suppl), pp. 29-35. | Citations: 54 (Scopus) | Show Abstract

Severe malaria is a global problem, claiming at least 1 million lives annually. Few adequately powered clinical studies have been directed at improving the management of severe malaria over the years, but this situation is slowly changing. The antimalarial treatment of severe disease is being transformed by the development and deployment of the water-soluble artemisinin derivative artesunate. Parenteral artesunate is now the treatment of choice in low-transmission areas and in the 2nd and 3rd trimesters of pregnancy, and research is underway into whether it should replace quinine as the treatment of choice in African children. Development of good manufacturing practice (GMP) formulations should make parenteral artesunate more widely available in the near future. The development of artesunate suppositories offers another exciting prospect, the ability to treat patients with severe disease in remote rural settings, delaying the evolution of disease and buying them time to reach a health care facility. No adjunctive therapy has been shown to improve the outcome of severe malaria, but most studies have been underpowered. Future trials of interventions shown to be promising in pilot studies should be large and adequately powered. This will require multi-center designs and necessitate close collaboration between groups, as well as agreement on the research agenda. We suggest a list of candidate interventions for debate.

Breman JG, Alilio MS, White NJ. 2007. Defining and defeating the intolerable burden of malaria III. Progress and perspectives - Objectives and Acknowledgements AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 77 (6), pp. I-II. | Citations: 1 (Web of Science Lite) | Read more

Breman JG, Alilio MS, White NJ. 2007. Defining and defeating the intolerable burden of malaria III. Progress and perspectives AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 77 (6), pp. VI-XI. | Citations: 13 (Web of Science Lite) | Read more

Price RN, Tjitra E, Guerra CA, Yeung S, White NJ, Anstey NM. 2007. Vivax malaria: neglected and not benign. The American journal of tropical medicine and hygiene, 77 (6 Suppl), pp. 79-87. | Citations: 531 (Web of Science Lite) | Show Abstract | Read more

Plasmodium vivax threatens almost 40% of the world's population, resulting in 132-391 million clinical infections each year. Most of these cases originate from Southeast Asia and the Western Pacific, although a significant number also occurs in Africa and South America. Although often regarded as causing a benign and self-limiting infection, there is increasing evidence that the overall burden, economic impact, and severity of disease from P. vivax have been underestimated. Malaria control strategies have had limited success and are confounded by the lack of access to reliable diagnosis, emergence of multidrug resistant isolates, the parasite's ability to transmit early in the course of disease and relapse from dormant liver stages at varying time intervals after the initial infection. Progress in reducing the burden of disease will require improved access to reliable diagnosis and effective treatment of both blood-stage and latent parasites, and more detailed characterization of the epidemiology, morbidity, and economic impact of vivax malaria. Without these, vivax malaria will continue to be neglected by ministries of health, policy makers, researchers, and funding bodies.

Lubell Y, Reyburn H, Mbakilwa H, Mwangi R, Chonya K, Whitty CJM, Mills A. 2007. The cost-effectiveness of parasitologic diagnosis for malaria-suspected patients in an era of combination therapy. Am J Trop Med Hyg, 77 (6 Suppl), pp. 128-132. | Citations: 62 (Scopus) | Show Abstract | Read more

The introduction of artemisinin-based combination therapy in sub-Saharan Africa has prompted calls for increased use of parasitologic diagnosis for malaria. We evaluated the cost-effectiveness of rapid diagnostic tests (RDTs) in comparison to microscopy in guiding treatment of non-severe febrile illness at varying levels of malaria endemicity using data on test accuracy and costs collected as part of a Tanzanian trial. If prescribers complied with current guidelines, microscopy would give rise to lower average costs per patient correctly treated than RDTs in areas of both high and low transmission. RDT introduction would result in an additional 2.3% and 9.4% of patients correctly treated, at an incremental cost of $25 and $7 in the low and high transmission settings, respectively. Cost-effectiveness would be worse if prescribers do not comply with test results. The cost of this additional benefit may be higher than many countries can afford without external assistance or lower RDT prices.

Price RN, Tjitra E, Guerra CA, Yeung S, White NJ, Anstey NM. 2007. Vivax malaria: neglected and not benign. Am J Trop Med Hyg, 77 (6 Suppl), pp. 79-87. | Citations: 565 (Scopus) | Show Abstract

Plasmodium vivax threatens almost 40% of the world's population, resulting in 132-391 million clinical infections each year. Most of these cases originate from Southeast Asia and the Western Pacific, although a significant number also occurs in Africa and South America. Although often regarded as causing a benign and self-limiting infection, there is increasing evidence that the overall burden, economic impact, and severity of disease from P. vivax have been underestimated. Malaria control strategies have had limited success and are confounded by the lack of access to reliable diagnosis, emergence of multidrug resistant isolates, the parasite's ability to transmit early in the course of disease and relapse from dormant liver stages at varying time intervals after the initial infection. Progress in reducing the burden of disease will require improved access to reliable diagnosis and effective treatment of both blood-stage and latent parasites, and more detailed characterization of the epidemiology, morbidity, and economic impact of vivax malaria. Without these, vivax malaria will continue to be neglected by ministries of health, policy makers, researchers, and funding bodies.

Heiden D, Ford N, Wilson D, Rodriguez WR, Margolis T, Janssens B, Bedelu M, Tun N, Goemaere E, Saranchuk P et al. 2007. Cytomegalovirus retinitis: the neglected disease of the AIDS pandemic. PLoS Med, 4 (12), pp. e334. | Citations: 75 (Scopus) | Read more

Chantratita N, Wuthiekanun V, Limmathurotsakul D, Thanwisai A, Chantratita W, Day NPJ, Peacock SJ. 2007. Prospective clinical evaluation of the accuracy of 16S rRNA real-time PCR assay for the diagnosis of melioidosis. Am J Trop Med Hyg, 77 (5), pp. 814-817. | Citations: 23 (Scopus) | Show Abstract | Read more

The accuracy of a Burkholderia pseudomallei 16s rRNA real-time PCR assay was evaluated against culture for the diagnosis of melioidosis in Thailand. A total of 846 samples were obtained from 383 patients with suspected melioidosis. One or more specimens were PCR positive for 47 of 77 patients with culture-proven melioidosis (sensitivity 61.0%, 95% CI: 49.2-72.0%). PCR was negative for all 306 patients who were culture negative for B. pseudomallei (specificity 100%, 95% CI: 98.8-100%). Diagnostic sensitivity of PCR was 22.7% for patients who were culture positive for blood only, compared with 79.4% for patients who were culture positive for samples other than blood. The median (interquartile range) B. pseudomallei colony count in blood for 44 of 77 patients with positive blood cultures was 2.4 CFU/ml (0.2-13.5 CFU/ml); this may explain the low sensitivity of PCR for this specimen. The PCR assay described here is not sufficiently sensitive to replace culture in our clinical setting.

Wuthiekanun V, Limmathurotsakul D, Wongsuvan G, Chierakul W, Teerawattanasook N, Teparrukkul P, Day NP, Peacock SJ. 2007. Quantitation of B. Pseudomallei in clinical samples. Am J Trop Med Hyg, 77 (5), pp. 812-813. | Citations: 23 (Web of Science Lite) | Show Abstract | Read more

We undertook a prospective study to quantitate Burkholderia pseudomallei in blood, urine, respiratory secretions, and pus [corrected] obtained from 414 patients with melioidosis. The median was count 1.1, 1.5 x 10(4), 1.1 x 10(5), and 1.1 x 10(7) CFU/mL in these sample types, respectively. This provides important insights into the likely feasibility of future studies such as expression microarray analysis using clinical material.

Amornchai P, Chierakul W, Wuthiekanun V, Mahakhunkijcharoen Y, Phetsouvanh R, Currie BJ, Newton PN, van Vinh Chau N, Wongratanacheewin S, Day NPJ, Peacock SJ. 2007. Accuracy of Burkholderia pseudomallei identification using the API 20NE system and a latex agglutination test. J Clin Microbiol, 45 (11), pp. 3774-3776. | Citations: 42 (Scopus) | Show Abstract | Read more

In an evaluation of the API 20NE for the identification of Burkholderia spp., 792/800 (99%) Burkholderia pseudomallei and 17/19 (89%) B. cepacia isolates were correctly identified but 10 B. mallei and 98 B. thailandensis isolates were not correctly identified. A latex agglutination test was positive for 796/800 (99.5%) B. pseudomallei isolates and negative for 120 other oxidase-positive gram-negative bacilli.

Blacksell SD, Bell D, Kelley J, Mammen MP, Gibbons RV, Jarman RG, Vaughn DW, Jenjaroen K, Nisalak A, Thongpaseuth S et al. 2007. Prospective study to determine accuracy of rapid serological assays for diagnosis of acute dengue virus infection in Laos. Clin Vaccine Immunol, 14 (11), pp. 1458-1464. | Citations: 31 (Scopus) | Show Abstract | Read more

There is an urgent need for accurate and simple dengue virus infection diagnostic assays in limited-resource settings of dengue endemicity, to assist patient management. Using a panel of reference samples (S. D. Blacksell, P. N. Newton, D. Bell, J. Kelley, M. P. Mammen, D. W. Vaughn, V. Wuthiekanun, A. Sungkakum, A. Nisalak, and N. P. Day, Clin. Infect. Dis. 42:1127-1134, 2006), we recently evaluated eihgt commercially available immunochromatographic rapid diagnostic tests (RDTs) designed to detect dengue virus-specific immunoglobulin M (IgM) and/or IgG. We found that 6/8 RDTs had sensitivities of less than 50% (range, 6 to 65%), but specificities were generally high. Here, in conjuction with dengue virus serotyping by reverse transcriptase PCR and in the limited-resource setting of Laos, where dengue virus is endemic, we evaluated the same eight RDTs against a previously validated dengue IgM/IgG enzyme-linked immunosorbent assay for diagnosis of acute dengue virus infection. Paired serum samples were collected from 87 patients, of whom 38 had confirmed dengue virus infections (4 had primary infections, 33 had secondary infections, and 1 had an infection of indeterminate status). RDT sensitivity was low, with 7/8 RDTs having admission sample sensitivities of less than 20% (range, 4 to 26%). The majority (6/8) of the RDTs, demonstrated high specificity (>95%). Kappa statistic values ranged from 6 to 54% for the RDTs, demonstrating poor to moderate variation between three operators. No RDT adequately differentiated between primary and secondary dengue virus infections. The findings of this study suggest that currently available RDTs based on the detection of IgM antibodies for the diagnosis of acute dengue virus infections are unlikely to be useful for patient management.

Keomany S, Mayxay M, Souvannasing P, Vilayhong C, Stuart BL, Srour L, Newton PN. 2007. Toad poisoning in Laos. Am J Trop Med Hyg, 77 (5), pp. 850-853. | Citations: 10 (Scopus) | Show Abstract | Read more

We describe two patients who developed severe illness after eating the skin and eggs of a toad, probably Bufo melanostictus Schneider, in southeastern Laos. One boy died, and one developed a digoxin toxicity-like syndrome with bradycardia and heart failure but survived. A telephone survey of 16 Lao provincial hospitals suggested that toad poisoning occurs in at least six provinces. That 93% of villagers in three villages in southeastern Laos were aware that toads are poisonous but that 51% had encountered patients with toad toxicity suggests that the potential gravity is not appreciated. These data indicate that toad poisoning may be underestimated and that education on the seriousness of toad toxins could be a useful public health measure.

Price RN, Hasugian AR, Ratcliff A, Siswantoro H, Purba HLE, Kenangalem E, Lindegardh N, Penttinen P, Laihad F, Ebsworth EP et al. 2007. Clinical and pharmacological determinants of the therapeutic response to dihydroartemisinin-piperaquine for drug-resistant malaria. Antimicrob Agents Chemother, 51 (11), pp. 4090-4097. | Citations: 71 (Scopus) | Show Abstract | Read more

Dihydroartemisinin-piperaquine (DHP) is an important new treatment for drug-resistant malaria, although pharmacokinetic studies on the combination are limited. In Papua, Indonesia, we assessed determinants of the therapeutic efficacy of DHP for uncomplicated malaria. Plasma piperaquine concentrations were measured on day 7 and day 28, and the cumulative risk of parasitological failure at day 42 was calculated using survival analysis. Of the 598 patients in the evaluable population 342 had infections with Plasmodium falciparum, 83 with Plasmodium vivax, and 173 with a mixture of both species. The unadjusted cumulative risks of recurrence were 7.0% (95% confidence interval [CI]: 4.6 to 9.4%) for P. falciparum and 8.9% (95% CI: 6.0 to 12%) for P. vivax. After correcting for reinfections the risk of recrudescence with P. falciparum was 1.1% (95% CI: 0.1 to 2.1%). The major determinant of parasitological failure was the plasma piperaquine concentration. A concentration below 30 ng/ml on day 7 was observed in 38% (21/56) of children less than 15 years old and 22% (31/140) of adults (P = 0.04), even though the overall dose (mg per kg of body weight) in children was 9% higher than that in adults (P < 0.001). Patients with piperaquine levels below 30 ng/ml were more likely to have a recurrence with P. falciparum (hazard ratio [HR] = 6.6 [95% CI: 1.9 to 23]; P = 0.003) or P. vivax (HR = 9.0 [95% CI: 2.3 to 35]; P = 0.001). The plasma concentration of piperaquine on day 7 was the major determinant of the therapeutic response to DHP. Lower plasma piperaquine concentrations and higher failure rates in children suggest that dose revision may be warranted in this age group.

Limmathurotsakul D, Wuthiekanun V, Chantratita N, Wongsuvan G, Thanwisai A, Biaklang M, Tumapa S, Lee S, Day NPJ, Peacock SJ. 2007. Simultaneous infection with more than one strain of Burkholderia pseudomallei is uncommon in human melioidosis. J Clin Microbiol, 45 (11), pp. 3830-3832. | Citations: 14 (European Pubmed Central) | Show Abstract | Read more

A prospective study was performed to determine the rate at which patients with melioidosis are infected with more than one strain of Burkholderia pseudomallei. Genotyping of 2,058 bacterial colonies isolated from 215 samples taken from 133 patients demonstrated that mixed infection is uncommon (2/133 cases [1.5%; 95% confidence interval, 0.2 to 5.3%]).

Lindegårdh N, Hanpithakpong W, Wattanagoon Y, Singhasivanon P, White NJ, Day NPJ. 2007. Development and validation of a liquid chromatographic-tandem mass spectrometric method for determination of oseltamivir and its metabolite oseltamivir carboxylate in plasma, saliva and urine. J Chromatogr B Analyt Technol Biomed Life Sci, 859 (1), pp. 74-83. | Citations: 80 (Scopus) | Show Abstract | Read more

A bioanalytical method for the analysis of oseltamivir (OP) and its metabolite oseltamivir carboxylate (OC) in human plasma, saliva and urine using off-line solid-phase extraction and liquid chromatography coupled to positive tandem mass spectroscopy has been developed and validated. OP and OC were analysed on a ZIC-HILIC column (50 mm x 2.1 mm) using a mobile phase gradient containing acetonitrile-ammonium acetate buffer (pH 3.5; 10mM) at a flow rate of 500 microL/min. The method was validated according to published FDA guidelines and showed excellent performance. The lower limit of quantification for OP was determined to be 1, 1 and 5 ng/mL for plasma, saliva and urine, respectively and for OC was 10, 10 and 30 ng/mL for plasma, saliva and urine, respectively. The upper limit of quantification for OP was determined to be 600, 300 and 1500 ng/mL for plasma, saliva and urine, respectively and for OC was 10,000, 10,000 and 30,000 ng/mL for plasma, saliva and urine, respectively. The within-day and between-day precisions expressed as R.S.D., were lower than 5% at all tested concentrations for all matrices and below 12% at the lower limit of quantification. Validation of over-curve samples ensured that it would be possible with dilution if samples went outside the calibration range. Matrix effects were thoroughly evaluated both graphically and quantitatively. No matrix effects were detected for OP or OC in plasma or saliva. Residues from the urine matrix (most likely salts) caused some ion suppression for both OP and its deuterated internal standard but had no effect on OC or its deuterated internal standard. The suppression did not affect the quantification of OP.

Ricci C, Eliasson C, Macleod NA, Newton PN, Matousek P, Kazarian SG. 2007. Characterization of genuine and fake artesunate anti-malarial tablets using Fourier transform infrared imaging and spatially offset Raman spectroscopy through blister packs. Anal Bioanal Chem, 389 (5), pp. 1525-1532. | Citations: 90 (Scopus) | Show Abstract | Read more

In support of the efforts to combat the illegal sale and distribution of counterfeit anti-malarial drugs, we evaluated a new analytical approach for the characterization and fast screening of fake and genuine artesunate tablets using a combination of Raman spectroscopy, Spatially Offset Raman Spectroscopy (SORS) and Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) imaging. Vibrational spectroscopy provided chemically specific information on the composition of the tablets; the complementary nature of Raman scattering and FTIR imaging allowed the characterization of both the overall and surface composition of the tablets. The depth-resolving power of the SORS approach provided chemically specific information on the overall composition of the tablets, non-invasively, through a variety of packaging types. Spatial imaging of the tablet surface (using ATR-FTIR) identified the location of domains of excipients and active ingredients with high sensitivity and enhanced spatial resolution. The advantages provided by a combination of SORS and ATR-FTIR imaging in this context confirm its potential for inclusion in the analytical protocol for forensic investigation of counterfeit medicines.

Paris DH, Imwong M, Faiz AM, Hasan M, Yunus EB, Silamut K, Lee SJ, Day NPJ, Dondorp AM. 2007. Loop-mediated isothermal PCR (LAMP) for the diagnosis of falciparum malaria. Am J Trop Med Hyg, 77 (5), pp. 972-976. | Citations: 86 (Scopus) | Show Abstract | Read more

A recently described loop-mediated isothermal polymerase chain reaction (LAMP) for molecular detection of Plasmodium falciparum was compared with microscopy, PfHRP2-based rapid diagnostic test (RDT), and nested polymerase chain reaction (PCR) as the "gold standard" in 115 Bangladeshi in-patients with fever. DNA extraction for LAMP was conducted by conventional methods or simple heating of the sample; test results were either assessed visually or by gel electrophoresis. Conventional DNA extraction followed by gel electrophoresis had the highest agreement with the reference method (81.7%, kappa = 0.64), with a sensitivity (95% CI) of 76.1% (68.3-83.9%), comparable to RDT and microscopy, but a specificity of 89.6% (84.0-95.2%) compared with 100% for RDT and microscopy. DNA extraction by heat treatment deteriorated specificity to unacceptable levels. LAMP enables molecular diagnosis of falciparum malaria in settings with limited technical resources but will need further optimization. The results are in contrast with a higher accuracy reported in an earlier study comparing LAMP with a non-validated PCR method.

Currie BJ, Thomas AD, Godoy D, Dance DA, Cheng AC, Ward L, Mayo M, Pitt TL, Spratt BG. 2007. Australian and Thai isolates of Burkholderia pseudomallei are distinct by multilocus sequence typing: revision of a case of mistaken identity. J Clin Microbiol, 45 (11), pp. 3828-3829. | Citations: 16 (Scopus) | Show Abstract | Read more

A recent study using multilocus sequence typing (MLST) of Burkholderia pseudomallei isolates found a sequence type (ST60) to be common to both Thailand and Australia, contradicting earlier studies showing complete distinction between isolates from these regions. The ST60 isolates reportedly from Australia had been obtained for MLST from United Kingdom and U.S. collections. We have located and characterized the original Australian isolates; they were collected in 1983, and they are neither ST60 nor B. pseudomallei isolates. The B. pseudomallei MLST database has been corrected, and there is no ST common to isolates verified as obtained from Australia or from Thailand.

Yeo TW, Lampah DA, Gitawati R, Tjitra E, Kenangalem E, McNeil YR, Darcy CJ, Granger DL, Weinberg JB, Lopansri BK et al. 2007. Impaired nitric oxide bioavailability and L-arginine reversible endothelial dysfunction in adults with falciparum malaria. J Exp Med, 204 (11), pp. 2693-2704. | Citations: 197 (Scopus) | Show Abstract | Read more

Severe falciparum malaria (SM) is associated with tissue ischemia related to cytoadherence of parasitized erythrocytes to microvascular endothelium and reduced levels of NO and its precursor, l-arginine. Endothelial function has not been characterized in SM but can be improved by l-arginine in cardiovascular disease. In an observational study in Indonesia, we measured endothelial function using reactive hyperemia-peripheral arterial tonometry (RH-PAT) in 51 adults with SM, 48 patients with moderately severe falciparum malaria (MSM), and 48 controls. The mean RH-PAT index was lower in SM (1.41; 95% confidence interval [CI] = 1.33-1.47) than in MSM (1.82; 95% CI = 1.7-2.02) and controls (1.93; 95% CI = 1.8-2.06; P < 0.0001). Endothelial dysfunction was associated with elevated blood lactate and measures of hemolysis. Exhaled NO was also lower in SM relative to MSM and controls. In an ascending dose study of intravenous l-arginine in 30 more patients with MSM, l-arginine increased the RH-PAT index by 19% (95% CI = 6-34; P = 0.006) and exhaled NO by 55% (95% CI = 32-73; P < 0.0001) without important side effects. Hypoargininemia and hemolysis likely reduce NO bioavailability. Endothelial dysfunction in malaria is nearly universal in severe disease, is reversible with l-arginine, and likely contributes to its pathogenesis. Clinical trials in SM of adjunctive agents to improve endothelial NO bioavailability, including l-arginine, are warranted.

Thaipadungpanit J, Wuthiekanun V, Chierakul W, Smythe LD, Petkanchanapong W, Limpaiboon R, Apiwatanaporn A, Slack AT, Suputtamongkol Y, White NJ et al. 2007. A dominant clone of Leptospira interrogans associated with an outbreak of human leptospirosis in Thailand. PLoS Negl Trop Dis, 1 (1), pp. e56. | Citations: 115 (Scopus) | Show Abstract | Read more

BACKGROUND: A sustained outbreak of leptospirosis occurred in northeast Thailand between 1999 and 2003, the basis for which was unknown. METHODS AND FINDINGS: A prospective study was conducted between 2000 and 2005 to identify patients with leptospirosis presenting to Udon Thani Hospital in northeast Thailand, and to isolate the causative organisms from blood. A multilocus sequence typing scheme was developed to genotype these pathogenic Leptospira. Additional typing was performed for Leptospira isolated from human cases in other Thai provinces over the same period, and from rodents captured in the northeast during 2004. Sequence types (STs) were compared with those of Leptospira drawn from a reference collection. Twelve STs were identified among 101 isolates from patients in Udon Thani. One of these (ST34) accounted for 77 (76%) of isolates. ST34 was Leptospira interrogans, serovar Autumnalis. 86% of human Leptospira isolates from Udon Thani corresponded to ST34 in 2000/2001, but this figure fell to 56% by 2005 as the outbreak waned (p = 0.01). ST34 represented 17/24 (71%) of human isolates from other Thai provinces, and 7/8 (88%) rodent isolates. By contrast, 59 STs were found among 76 reference strains, indicating a much more diverse population genetic structure; ST34 was not identified in this collection. CONCLUSIONS: Development of an MLST scheme for Leptospira interrogans revealed that a single ecologically successful pathogenic clone of L. interrogans predominated in the rodent population, and was associated with a sustained outbreak of human leptospirosis in Thailand.

Nuchsongsin F, Chotivanich K, Charunwatthana P, Omodeo-Salè F, Taramelli D, Day NP, White NJ, Dondorp AM. 2007. Effects of malaria heme products on red blood cell deformability. Am J Trop Med Hyg, 77 (4), pp. 617-622. | Citations: 33 (Scopus) | Show Abstract | Read more

In falciparum malaria, the deformability of the entire erythrocyte population is reduced in proportion to disease severity, and this compromises microcirculatory blood flow through vessels partially obstructed by cytoadherent parasitized erythrocytes. The cause of rigidity of uninfected erythrocytes in not known but could be mediated by malaria heme products. In this study, we show that red blood cell deformability (RBC-D), measured by laser-assisted optical rotational cell analyzer, decreased in a dose-dependent manner after incubation with hemin and hydrogen peroxide but not with hemoglobin or beta-hematin. Hemin also reduced mean red cell volume. Albumin decreased and N-acetylcysteine (NAC) both prevented and reversed rigidity induced by hemin. Hemin-induced oxidative damage of the membrane seems to be a more important contributor to pathology than cell shrinkage because the antioxidant NAC restored RBC-D but not red blood cell volume. The findings suggest novel approaches to the treatment of potentially lethal malaria.

Newton PN, Mayxay M, Taylor A, White NJ. 2007. Untitled TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 (10), pp. 1272-1273.

Khor CC, Vannberg FO, Chapman SJ, Walley A, Aucan C, Loke H, White NJ, Peto T, Khor LK, Kwiatkowski D et al. 2007. Positive replication and linkage disequilibrium mapping of the chromosome 21q22.1 malaria susceptibility locus. Genes Immun, 8 (7), pp. 570-576. | Citations: 15 (Web of Science Lite) | Show Abstract | Read more

Four cytokine receptor genes are located on Chr21q22.11, encoding the alpha and beta subunits of the interferon-alpha receptor (IFNAR1 and IFNAR2), the beta subunit of the interleukin 10 receptor (IL10RB) and the second subunit of the interferon-gamma receptor (IFNGR2). We previously reported that two variants in IFNAR1 were associated with susceptibility to malaria in Gambians. We now present an extensive fine-scale mapping of the associated region utilizing 45 additional genetic markers obtained from public databases and by sequencing a 44 kb region in and around the IFNAR1 gene in 24 Gambian children (12 cases/12 controls). Within the IFNAR1 gene, a newly studied C --> G single-nucleotide polymorphism (IFNAR1 272354c-g) at position -576 relative to the transcription start was found to be more strongly associated with susceptibility to severe malaria. Association was observed in three populations: in Gambian (P=0.002), Kenyan (P=0.022) and Vietnamese (P=0.005) case-control studies. When all three studies were combined, using the Mantel-Haenszel test, the presence of IFNAR1 -576G was associated with a substantially elevated risk of severe malaria (N=2444, OR=1.38, 95% CI: 1.17-1.64; P=1.7 x 10(-4)). This study builds on previous work to further highlight the importance of the type-I interferon pathway in malaria susceptibility and illustrates the utility of typing SNPs within regions of high linkage disequilibrium in multiple populations to confirm initial positive associations.

Tanomsing N, Imwong M, Pukrittayakamee S, Chotivanich K, Looareesuwan S, Mayxay M, Dolecek C, Hien TT, do Rosario VE, Arez AP et al. 2007. Genetic analysis of the dihydrofolate reductase-thymidylate synthase gene from geographically diverse isolates of Plasmodium malariae. Antimicrob Agents Chemother, 51 (10), pp. 3523-3530. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

Plasmodium malariae, the parasite responsible for quartan malaria, is transmitted in most areas of malaria endemicity and is associated with significant morbidity. The sequence of the gene coding for the enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) was obtained from field isolates of P. malariae and from the closely related simian parasite Plasmodium brasilianum. The two sequences were nearly 100% homologous, adding weight to the notion that they represent genetically distinct lines of the same species. A survey of polymorphisms of the dhfr sequences in 35 isolates of P. malariae collected from five countries in Asia and Africa revealed a low number of nonsynonymous mutations in five codons. In five of the isolates collected from southeast Asia, a nonsynonymous mutation was found at one of the three positions known to be associated with antifolate resistance in other Plasmodium species. Five isolates with the wild-type DHFR could be assayed for drug susceptibility in vitro and were found to be sensitive to pyrimethamine (mean 50% inhibitory concentration, 2.24 ng/ml [95% confidence interval, 0.4 to 3.1]).

Antarasena C, Sirimujalin R, Prommuang P, Promkuntod N, Prommuang P, Blacksell SD. 2007. The indirect immunofluorescence assay using cardiac tissue from chickens, quails and ducks for identification of influenza A virus during an outbreak of highly pathogenic avian influenza virus (H5N1): a rapid and simple screening tool for limited resource settings. Res Vet Sci, 83 (2), pp. 279-281. | Citations: 5 (Web of Science Lite) | Show Abstract | Read more

Here we describe the diagnostic utility of the indirect immunofluorescence assay (IFA) during a recent outbreak of highly pathogenic avian influenza (HPAI) subtype H5N1 virus in southern Thailand and demonstrate the usefulness of the cardiac tissue from infected chickens, quail, and ducks for diagnosis. The most reliable sample for IFA diagnosis of influenza A virus was cardiac tissue (83.0%; 44/53) which when divided by species (chicken, quail and duck cardiac tissues) gave respective positivity rates of 88% (22/25), 88.9% (16/18) and 60.0% (6/10). Cardiac tissue also gave the highest IFA intensity for the three species. We believe that the IFA method has wide applicability in developing countries or remote settings where clinically similar avian diseases with high morbidity and mortality such as Newcastle disease and fowl cholera are common and could be rapidly excluded thereby conserving valuable reference laboratory capacity for true HPAI outbreaks.

Newton PN, Mayxay M, Taylor A, White NJ. 2007. Letters to the editors Tropical Medicine & International Health, 12 (10), pp. 1272-1273. | Read more

Hanson JP, Dondorp AM, Day NPJ. 2007. Malaria treatment in the United States. JAMA, 298 (12), pp. 1396. | Citations: 1 (European Pubmed Central) | Read more

Lindegårdh N, Dondorp AM, Singhasivanon P, White NJ, Day NPJ. 2007. Validation and application of a liquid chromatographic-mass spectrometric method for determination of artesunate in pharmaceutical samples. J Pharm Biomed Anal, 45 (1), pp. 149-153. | Citations: 28 (Scopus) | Show Abstract | Read more

A simple and rapid liquid chromatographic-mass spectrometric assay for the evaluation of artesunate in vials for injection has been developed and validated. The content of each vial was dissolved in 3.0 mL of methanol using a SGE analytical syringe (1.0 mL). Each sample was diluted to a theoretical concentration of 1000 ng/mL and analysed in triplicate. Three replicates of calibration standards at concentrations 500, 1000 and 1500 ng/mL were used to construct a calibration curve. Artesunate was analysed by liquid chromatography with atmospheric pressure chemical ionisation (APCI) mass spectrometric (MS) detection on a Hypersil Gold column (100 mm x 4.6 mm) using a mobile phase containing methanol-ammonium acetate 10 mM pH 5.3 (70:30, v/v) at a flow rate of 1 mL/min. The assay was implemented for the analysis of artesunate for injection purchased from Guilin Pharmaceutical Company in China.

Boonma P, Christensen PR, Suwanarusk R, Price RN, Russell B, Lek-Uthai U. 2007. Comparison of three molecular methods for the detection and speciation of Plasmodium vivax and Plasmodium falciparum. Malar J, 6 (1), pp. 124. | Citations: 56 (Scopus) | Show Abstract | Read more

BACKGROUND: Accurate diagnosis of Plasmodium spp. is essential for the rational treatment of malaria. Despite its many disadvantages, microscopic examination of blood smears remains the current "gold standard" for malaria detection and speciation. PCR assays offer an alternative to microscopy which has been shown to have superior sensitivity and specificity. Unfortunately few comparative studies have been done on the various molecular based speciation methods. METHODS: The sensitivity, specificity and cost effectiveness of three molecular techniques were compared for the detection and speciation of Plasmodium falciparum and Plasmodium vivax from dried blood spots collected from 136 patients in western Thailand. The results from the three molecular speciation techniques (nested PCR, multiplex PCR, and real-time PCR) were used to develop a molecular consensus (two or more identical PCR results) as an alternative gold standard. RESULTS: According to the molecular consensus, 9.6% (13/136) of microscopic diagnoses yielded false negative results. Multiplex PCR failed to detect P. vivax in three mixed isolates, and the nested PCR gave a false positive P. falciparum result in one case. Although the real-time PCR melting curve analysis was the most expensive method, it was 100% sensitive and specific and least time consuming of the three molecular techniques investigated. CONCLUSION: Although microscopy remains the most appropriate method for clinical diagnosis in a field setting, its use as a gold standard may result in apparent false positive results by superior techniques. Future studies should consider using more than one established molecular methods as a new gold standard to assess novel malaria diagnostic kits and PCR assays.

Price RN, Dorsey G, Ashley EA, Barnes KI, Baird JK, d'Alessandro U, Guerin PJ, Laufer MK, Naidoo I, Nosten F et al. 2007. World Antimalarial Resistance Network I: clinical efficacy of antimalarial drugs. Malar J, 6 (1), pp. 119. | Citations: 47 (Scopus) | Show Abstract | Read more

The proliferation of antimalarial drug trials in the last ten years provides the opportunity to launch a concerted global surveillance effort to monitor antimalarial drug efficacy. The diversity of clinical study designs and analytical methods undermines the current ability to achieve this. The proposed World Antimalarial Resistance Network (WARN) aims to establish a comprehensive clinical database from which standardised estimates of antimalarial efficacy can be derived and monitored over time from diverse geographical and endemic regions. The emphasis of this initiative is on five key variables which define the therapeutic response. Ensuring that these data are collected at the individual patient level in a consistent format will facilitate better data management and analytical practices, and ensure that clinical data can be readily collated and made amenable for pooled analyses. Such an approach, if widely adopted will permit accurate and timely recognition of trends in drug efficacy. This will guide not only appropriate interventions to deal with established multidrug resistant strains of malaria, but also facilitate prompt action when new strains of drug resistant plasmodia first emerge. A comprehensive global database incorporating the key determinants of the clinical response with in vitro, molecular and pharmacokinetic parameters will bring together relevant data on host, drug and parasite factors that are fundamental contributors to treatment efficacy. This resource will help guide rational drug policies that optimize antimalarial drug use, in the hope that the emergence and spread of resistance to new drugs can be, if not prevented, at least delayed.

Phimda K, Hoontrakul S, Suttinont C, Chareonwat S, Losuwanaluk K, Chueasuwanchai S, Chierakul W, Suwancharoen D, Silpasakorn S, Saisongkorh W et al. 2007. Doxycycline versus azithromycin for treatment of leptospirosis and scrub typhus. Antimicrob Agents Chemother, 51 (9), pp. 3259-3263. | Citations: 98 (Scopus) | Show Abstract | Read more

Leptospirosis and scrub typhus are important causes of acute fever in Southeast Asia. Options for empirical therapy include doxycycline and azithromycin, but it is unclear whether their efficacies are equivalent. We conducted a multicenter, open, randomized controlled trial with adult patients presenting with acute fever (<15 days), without an obvious focus of infection, at four hospitals in Thailand between July 2003 and January 2005. Patients were randomly allocated to receive either a 7-day course of doxycycline or a 3-day course of azithromycin. The cure rate, fever clearance time, and adverse drug events were compared between the two study groups. A total of 296 patients were enrolled in the study. The cause of acute fever was determined for 151 patients (51%): 69 patients (23.3%) had leptospirosis; 57 patients (19.3%) had scrub typhus; 14 patients (4.7%) had murine typhus; and 11 patients (3.7%) had evidence of both leptospirosis and a rickettsial infection. The efficacy of azithromycin was not inferior to that of doxycycline for the treatment of both leptospirosis and scrub typhus, with comparable fever clearance times in the two treatment arms. Adverse events occurred more frequently in the doxycycline group than in the azithromycin group (27.6% and 10.6%, respectively; P = 0.02). In conclusion, doxycycline is an affordable and effective choice for the treatment of both leptospirosis and scrub typhus. Azithromycin was better tolerated than doxycycline but is more expensive and less readily available.

Mytton OT, Ashley EA, Peto L, Price RN, La Y, Hae R, Singhasivanon P, White NJ, Nosten F. 2007. Electrocardiographic safety evaluation of dihydroartemisinin piperaquine in the treatment of uncomplicated falciparum malaria. Am J Trop Med Hyg, 77 (3), pp. 447-450. | Citations: 32 (Scopus) | Show Abstract | Read more

Dihydroartemisinin-piperaquine (DP) could become a leading fixed combination malaria treatment worldwide. Although there is accumulating evidence of efficacy and safety from clinical trials, data on cardiotoxicity are limited. In two randomized controlled trials in Thailand, 56 patients had ECGs performed before treatment, 4 hours after the first dose, and 4 hours after the last dose. The mean (95% CI) changes in QTc interval (Bazett's correction) were 2 (-6 to 9) ms and 14 (7 to 21) ms, respectively. These small changes on the third day of treatment are similar to those observed elsewhere in the convalescent phase following antimalarial treatment with drugs known to have no cardiac effects and are therefore likely to result from recovery from acute malaria and not the treatment given. At therapeutic doses, DP does not have clinically significant effects on the electrocardiogram.

Myint HY, Ashley EA, Day NPJ, Nosten F, White NJ. 2007. Efficacy and safety of dihydroartemisinin-piperaquine. Trans R Soc Trop Med Hyg, 101 (9), pp. 858-866. | Citations: 68 (Web of Science Lite) | Show Abstract | Read more

Dihydroartemisinin-piperaquine, a fixed-dose combination antimalarial, is an inexpensive, safe and highly effective treatment for uncomplicated falciparum or vivax malaria. Efficacy assessed over 28-63 days has consistently exceeded 95% in the treatment of multidrug-resistant falciparum malaria. More than 2600 patients have been treated with this combination in prospective studies, mainly in Southeast Asia. Tolerability was uniformly good, and no serious adverse effects have been identified. The dosing regimen has been simplified from four doses to once daily over 3 days. More information on efficacy in Africa, and more pharmacokinetic and efficacy data in children are needed.

Arreesrisom P, Dondorp AM, Looareesuwan S, Udomsangpetch R. 2007. Suppressive effects of the anti-oxidant N-acetylcysteine on the anti-malarial activity of artesunate. Parasitol Int, 56 (3), pp. 221-226. | Citations: 19 (Scopus) | Show Abstract | Read more

The anti-oxidant drug N-acetylcysteine (NAC) has been proposed as adjunctive treatment in severe falciparum malaria. However, this might inhibit the anti-malarial drug action of the artemisinins, which are thought to exert their parasitocidal action through oxidative damage. We studied the interaction between NAC and artesunate as well as quinine in an in vitro drug sensitivity assay. Combination with NAC reduced the parasitocidal effect of artesunate only within the first 6 h of incubation, whereas no interaction was observed with quinine. Pre-incubation of P. falciparum with NAC resulted in a similar inhibitory effect on the anti-malarial activity of artesunate, whereas no inhibition was observed when NAC was added 2 h after parasite exposure to artesunate. Assessment of parasite maturation inhibition by the standard Giemsa's staining was in accordance with the use of a vital staining. The results herein caution the use of adjunctive treatment for malaria infection. Combination of antagonistic drugs may lead to adverse effects.

Nguansangiam S, Day NPJ, Hien TT, Mai NTH, Chaisri U, Riganti M, Dondorp AM, Lee SJ, Phu NH, Turner GDH et al. 2007. A quantitative ultrastructural study of renal pathology in fatal Plasmodium falciparum malaria. Trop Med Int Health, 12 (9), pp. 1037-1050. | Citations: 62 (Scopus) | Show Abstract | Read more

OBJECTIVE: To use electron microscopy to examine the role of parasitized red blood cell (PRBC) sequestration in the pathogenesis of acute renal failure in severe falciparum malaria. METHODS: Ultrastructural pathological examination of renal tissues from Southeast Asian adults (n = 63) who died from severe falciparum malaria. Qualitative and quantitative determination of the major pathological features of disease, including PRBC and leukocyte sequestration. Clinico-pathological correlation with the pre-mortem clinical picture and peripheral parasite count. RESULTS: There was a high incidence of malaria-associated renal failure in this population (> 40%) and a correlation between this incidence, severe malarial anaemia and shock. Pathological features included PRBC sequestration in glomerular and tubulo-interstitial vessels, acute tubular damage and mild glomerular hypercellularity resulting from the accumulation of host monocytes within glomerular capillaries. No evidence for an immune complex mediated glomerulonephritis was found. There was a correlation between parasite sequestration in the kidney and pre-mortem renal failure, although overall levels of sequestration were relatively low. Levels of sequestration (Knob+ PRBC) were significantly higher in malaria-associated renal failure than in fatal cases without renal failure (P = 0.005). CONCLUSION: Malaria-associated renal failure is a common and serious complication of severe Plasmodium falciparum malaria in this population, associated with acute tubular injury rather than glomerulonephritis, and linked to localization of host monocytes in the kidney as well as sequestration of PRBCs.

White LJ, Mandl JN, Gomes MGM, Bodley-Tickell AT, Cane PA, Perez-Brena P, Aguilar JC, Siqueira MM, Portes SA, Straliotto SM et al. 2007. Understanding the transmission dynamics of respiratory syncytial virus using multiple time series and nested models. Math Biosci, 209 (1), pp. 222-239. | Citations: 43 (Scopus) | Show Abstract | Read more

The nature and role of re-infection and partial immunity are likely to be important determinants of the transmission dynamics of human respiratory syncytial virus (hRSV). We propose a single model structure that captures four possible host responses to infection and subsequent reinfection: partial susceptibility, altered infection duration, reduced infectiousness and temporary immunity (which might be partial). The magnitude of these responses is determined by four homotopy parameters, and by setting some of these parameters to extreme values we generate a set of eight nested, deterministic transmission models. In order to investigate hRSV transmission dynamics, we applied these models to incidence data from eight international locations. Seasonality is included as cyclic variation in transmission. Parameters associated with the natural history of the infection were assumed to be independent of geographic location, while others, such as those associated with seasonality, were assumed location specific. Models incorporating either of the two extreme assumptions for immunity (none or solid and lifelong) were unable to reproduce the observed dynamics. Model fits with either waning or partial immunity to disease or both were visually comparable. The best fitting structure was a lifelong partial immunity to both disease and infection. Observed patterns were reproduced by stochastic simulations using the parameter values estimated from the deterministic models.

Cockburn R, Newton PN, Agyarko EK, Akunyili D, White NJ. 2007. Correction: The Global Threat of Counterfeit Drugs: Why Industry and Governments Must Communicate the Dangers PLoS Medicine, 4 (9), pp. e289-e289. | Citations: 3 (Scopus) | Read more

Chierakul W, Anunnatsiri S, Chaowagul W, Peacock SJ, Chetchotisakd P, Day NP. 2007. Addition of trimethoprim-sulfamethoxazole to ceftazidime during parenteral treatment of melioidosis is not associated with a long-term outcome benefit CLINICAL INFECTIOUS DISEASES, 45 (4), pp. 521-523. | Citations: 11 (Scopus) | Read more

Anstey NM, Pain MCF, Price RN, Maguire GP. 2007. Tumor necrosis factor and increase in alveolar capillary barrier in malaria - Reply to Eisenhut JOURNAL OF INFECTIOUS DISEASES, 196 (4), pp. 647-648. | Read more

Chierakul W, Anunnatsiri S, Chaowagul W, Peacock SJ, Chetchotisakd P, Day NP. 2007. Addition of trimethoprim-sulfamethoxazole to ceftazidime during parenteral treatment of melioidosis is not associated with a long-term outcome benefit. Clin Infect Dis, 45 (4), pp. 521-523. | Citations: 9 (European Pubmed Central) | Read more

Wiersinga WJ, Wieland CW, van der Windt GJW, de Boer A, Florquin S, Dondorp A, Day NP, Peacock SJ, van der Poll T. 2007. Endogenous interleukin-18 improves the early antimicrobial host response in severe melioidosis. Infect Immun, 75 (8), pp. 3739-3746. | Citations: 33 (Scopus) | Show Abstract | Read more

Melioidosis is caused by the soil saprophyte Burkholderia pseudomallei and is endemic in Southeast Asia. The pathogenesis of melioidosis is still largely unknown, although gamma interferon (IFN-gamma) seems to play an obligatory role in host defense. Previously, we have shown that IFN-gamma production in melioidosis is controlled in part by interleukin-18 (IL-18). The aim of the present study was to determine the role of IL-18 in the immune response to B. pseudomallei. For this the following investigations were performed. (i) Plasma IL-18 and blood monocyte IL-18 mRNA levels were elevated in 34 patients with culture-proven melioidosis compared to the levels in 32 local healthy controls; in addition, IL-18 binding protein levels were markedly elevated in patients, strongly correlating with mortality. (ii) IL-18 gene-deficient (IL-18 knockout [KO]) mice showed accelerated mortality after intranasal infection with a lethal dose of B. pseudomallei, which was accompanied by enhanced bacterial growth in their lungs, livers, spleens, kidneys, and blood at 24 and 48 h postinfection, compared to wild-type mice. In addition, IL-18 KO mice displayed evidence of enhanced hepatocellular injury and renal insufficiency. Together, these data indicate that the enhanced production of IL-18 in melioidosis is an essential part of a protective immune response to this severe infection.

Cheng AC, Limmathurotsakul D, Chierakul W, Getchalarat N, Wuthiekanun V, Stephens DP, Day NPJ, White NJ, Chaowagul W, Currie BJ, Peacock SJ. 2007. A randomized controlled trial of granulocyte colony-stimulating factor for the treatment of severe sepsis due to melioidosis in Thailand. Clin Infect Dis, 45 (3), pp. 308-314. | Citations: 63 (Scopus) | Show Abstract | Read more

BACKGROUND: Melioidosis is a tropical infectious disease associated with significant mortality. Most deaths occur early and are caused by fulminant sepsis. METHODS: In this randomized, placebo-controlled trial, we assessed the efficacy of lenograstim (granulocyte colony-stimulating factor [G-CSF], 263 mu g per day administered intravenously) in ceftazidime-treated patients with severe sepsis caused by suspected melioidosis in Thailand. RESULTS: Over a 27-month period, 60 patients were enrolled to receive either G-CSF (30 patients, 18 of whom had culture-confirmed melioidosis) or placebo (30 patients, 23 of whom had culture-confirmed melioidosis). Mortality rates were similar in both groups (G-CSF group, 70%; placebo group, 87%; risk ratio, 0.81; 95% confidence interval, 0.61-1.06; P=.2), including among patients with confirmed melioidosis (83% vs. 96%; P=.3). The duration of survival was longer for patients who received G-CSF than for patients who received placebo (33 h vs. 18.6 h; hazard ratio, 0.56; 95% confidence interval, 0.31-1.00; P=.05). CONCLUSIONS: Receipt of G-CSF is associated with a longer duration of survival but is not associated with a mortality benefit in patients with severe sepsis who are suspected of having melioidosis in Thailand. We hypothesize that G-CSF may "buy time" for severely septic patients, but survival is more likely to be improved by management of associated metabolic abnormalities and organ dysfunction associated with severe sepsis.

Dondorp AM, Silamut K, Charunwatthana P, Chuasuwanchai S, Ruangveerayut R, Krintratun S, White NJ, Ho M, Day NPJ. 2007. Levamisole inhibits sequestration of infected red blood cells in patients with falciparum malaria. J Infect Dis, 196 (3), pp. 460-466. | Citations: 36 (Scopus) | Show Abstract | Read more

BACKGROUND: Sequestration of infected red blood cells (iRBCs) in the microcirculation is central to the pathophysiology of falciparum malaria. It is caused by cytoadhesion of iRBCs to vascular endothelium, mediated through the binding of Plasmodium falciparum erythrocyte membrane protein-1 to several endothelial receptors. Binding to CD36, the major vascular receptor, is stabilized through dephosphorylation of CD36 by an alkaline phosphatase. This is inhibited by the alkaline phosphatase-inhibitor levamisole, resulting in decreased cytoadhesion. METHODS: Patients with uncomplicated falciparum malaria were randomized to receive either quinine treatment alone or treatment with a single 150-mg dose of levamisole as an adjunct to quinine. Peripheral blood parasitemia and parasite stage distribution were monitored closely over time. RESULTS: Compared with those in control subjects, peripheral blood parasitemias of mature P. falciparum parasites increased during the 24 h after levamisole administration (n=21; P=.006). The sequestration ratio (between observed and expected peripheral blood parasitemia) of early trophozoite and midtrophozoite parasites increased after levamisole treatment, with near complete prevention of early trophozoite sequestration and >65% prevention of midtrophozoite sequestration. CONCLUSION: These findings strongly suggest that levamisole decreases iRBC sequestration in falciparum malaria in vivo and should be considered as a potential adjunctive treatment for severe falciparum malaria. TRIAL REGISTRATION: Current Controlled Trials identifier: 15314870.

White NJ. 2007. Cardiotoxicity of antimalarial drugs. Lancet Infect Dis, 7 (8), pp. 549-558. | Citations: 151 (Scopus) | Show Abstract | Read more

There are consistent differences in cardiovascular state between acute illness in malaria and recovery that prolong the electrocardiographic QT interval and have been misinterpreted as resulting from antimalarial cardiotoxicity. Of the different classes of antimalarial drugs, only the quinolines, and structurally related antimalarial drugs, have clinically significant cardiovascular effects. Drugs in this class can exacerbate malaria-associated orthostatic hypotension and several have been shown to delay ventricular depolarisation slightly (class 1c effect), resulting in widening of the QRS complex, but only quinidine and halofantrine have clinically significant effects on ventricular repolarisation (class 3 effect). Both drugs cause potentially dangerous QT prolongation, and halofantrine has been associated with sudden death. The parenteral quinoline formulations (chloroquine, quinine, and quinidine) are predictably hypotensive when injected rapidly, and cardiovascular collapse can occur with self-poisoning. Transiently hypotensive plasma concentrations of chloroquine can occur when doses of 5 mg base/kg or more are given by intramuscular or subcutaneous injection. At currently recommended doses, other antimalarial drugs do not have clinically significant cardiac effects. More information on amodiaquine, primaquine, and the newer structurally related compounds is needed.

Anstey NM, Price RN. 2007. Improving case definitions for severe malaria. PLoS Med, 4 (8), pp. e267. | Citations: 23 (Web of Science Lite) | Read more

Chapman SJ, Khor CC, Vannberg FO, Frodsham A, Walley A, Maskell NA, Davies CWH, Segal S, Moore CE, Gillespie SH et al. 2007. IkappaB genetic polymorphisms and invasive pneumococcal disease. Am J Respir Crit Care Med, 176 (2), pp. 181-187. | Citations: 66 (Scopus) | Show Abstract | Read more

RATIONALE: Increasing evidence supports a key role for the transcription factor nuclear factor (NF)-kappaB in the host response to pneumococcal infection. Control of NF-kappaB activity is achieved through interactions with the IkappaB family of inhibitors, encoded by the genes NFKBIA, NFKBIB, and NFKBIE. Rare NFKBIA mutations cause immunodeficiency with severe bacterial infection, raising the possibility that common IkappaB gene polymorphisms confer susceptibility to common bacterial disease. OBJECTIVES: To determine whether polymorphisms in NFKBIA, NFKBIB, and NFKBIE associate with susceptibility to invasive pneumococcal disease (IPD) and thoracic empyema. METHODS: We studied the frequencies of 62 single-nucleotide polymorphisms (SNPs) across NFKBIA, NFKBIB, and NFKBIE in individuals with IPD and control subjects (n=1,060). Significantly associated SNPs were then studied in a group of individuals with thoracic empyema and a second control group (n=632). MEASUREMENTS AND MAIN RESULTS: Two SNPs in the NFKBIA promoter region were associated with protection from IPD in both the initial study group and the pneumococcal empyema subgroup. Significant protection from IPD was observed for carriage of mutant alleles at these two loci on combining the groups (SNP rs3138053: Mantel-Haenszel 2x2 chi2=13.030, p=0.0003; odds ratio [OR], 0.60; 95% confidence interval [CI], 0.45-0.79; rs2233406: Mantel-Haenszel 2x2 chi2=18.927, p=0.00001; OR, 0.55; 95% CI, 0.42-0.72). An NFKBIE SNP associated with susceptibility to IPD but not pneumococcal empyema. None of the NFKBIB SNPs associated with IPD susceptibility. CONCLUSIONS: NFKBIA polymorphisms associate with susceptibility to IPD. Genetic variation in an inhibitor of NF-kappaB therefore not only causes a very rare immunodeficiency state but may also influence the development of common infectious disease.

Wiersinga WJ, Wieland CW, Dessing MC, Chantratita N, Cheng AC, Limmathurotsakul D, Chierakul W, Leendertse M, Florquin S, de Vos AF et al. 2007. Toll-like receptor 2 impairs host defense in gram-negative sepsis caused by Burkholderia pseudomallei (Melioidosis). PLoS Med, 4 (7), pp. e248. | Citations: 106 (Scopus) | Show Abstract | Read more

BACKGROUND: Toll-like receptors (TLRs) are essential in host defense against pathogens by virtue of their capacity to detect microbes and initiate the immune response. TLR2 is seen as the most important receptor for gram-positive bacteria, while TLR4 is regarded as the gram-negative TLR. Melioidosis is a severe infection caused by the gram-negative bacterium, Burkholderia pseudomallei, that is endemic in Southeast Asia. We aimed to characterize the expression and function of TLRs in septic melioidosis. METHODS AND FINDINGS: Patient studies: 34 patients with melioidosis demonstrated increased expression of CD14, TLR1, TLR2, and TLR4 on the cell surfaces of monocytes and granulocytes, and increased CD14, TLR1, TLR2, TLR4, LY96 (also known as MD-2), TLR5, and TLR10 mRNA levels in purified monocytes and granulocytes when compared with healthy controls. In vitro experiments: Whole-blood and alveolar macrophages obtained from TLR2 and TLR4 knockout (KO) mice were less responsive to B. pseudomallei in vitro, whereas in the reverse experiment, transfection of HEK293 cells with either TLR2 or TLR4 rendered these cells responsive to this bacterium. In addition, the lipopolysaccharide (LPS) of B. pseudomallei signals through TLR2 and not through TLR4. Mouse studies: Surprisingly, TLR4 KO mice were indistinguishable from wild-type mice with respect to bacterial outgrowth and survival in experimentally induced melioidosis. In contrast, TLR2 KO mice displayed a markedly improved host defenses as reflected by a strong survival advantage together with decreased bacterial loads, reduced lung inflammation, and less distant-organ injury. CONCLUSIONS: Patients with melioidosis displayed an up-regulation of multiple TLRs in peripheral blood monocytes and granulocytes. Although both TLR2 and TLR4 contribute to cellular responsiveness to B. pseudomallei in vitro, TLR2 detects the LPS of B. pseudomallei, and only TLR2 impacts on the immune response of the intact host in vivo. Inhibition of TLR2 may be a novel treatment strategy in melioidosis.

Limmathurotsakul D, Chaowagul W, Wongsrikaew P, Narmwong A, Day NP, Peacock SJ. 2007. Variable presentation of neurological melioidosis in Northeast Thailand. Am J Trop Med Hyg, 77 (1), pp. 118-120. | Citations: 22 (Scopus) | Show Abstract | Read more

We describe three instructive cases of neurologic melioidosis that demonstrate the variable nature of clinical manifestations and disease pathology. The appropriate duration and choice of parenteral and oral antimicrobial therapy for neurologic melioidosis are also discussed.

Mayxay M, Nair S, Sudimack D, Imwong M, Tanomsing N, Pongvongsa T, Phompida S, Phetsouvanh R, White NJ, Anderson TJC, Newton PN. 2007. Combined molecular and clinical assessment of Plasmodium falciparum antimalarial drug resistance in the Lao People's Democratic Republic (Laos). Am J Trop Med Hyg, 77 (1), pp. 36-43. | Citations: 12 (Scopus) | Show Abstract | Read more

Molecular markers provide a rapid and relatively inexpensive approach for assessing antimalarial drug susceptibility. We collected 884 Plasmodium falciparum-infected blood samples from 17 Lao provinces. Each sample was genotyped for 11 codons in the chloroquine resistance transporter (pfcrt), dihydrofolate reductase (pfdhfr), and dihydropteroate synthase (pfdhps) genes. The samples included 227 collected from patients recruited to clinical trials. The pfcrt K76T mutation was an excellent predictor of treatment failure for both chloroquine and chloroquine plus sulfadoxine-pyrimethamine, and mutations in both pfdhfr and pfdhps were predictive of sulfadoxine-pyrimethamine treatment failure. In multivariate analysis, the presence of the pfdhfr triple mutation (51 + 59 + 108) was strongly and independently correlated with sulfadoxine-pyrimethamine failure (odds ratio = 9.1, 95% confidence interval = 1.4-60.2, P = 0.017). Considerable geographic heterogeneity in allele frequencies occurred at all three loci with lower frequencies of mutant alleles in southern than in northern Laos. These findings suggest that chloroquine and sulfadoxine-pyrimethamine are no longer viable therapy in this country.

Blacksell SD, Sharma NP, Phumratanaprapin W, Jenjaroen K, Peacock SJ, White NJ, Pukrittayakamee S, Day NPJ. 2007. Serological and blood culture investigations of Nepalese fever patients. Trans R Soc Trop Med Hyg, 101 (7), pp. 686-690. | Citations: 30 (Scopus) | Show Abstract | Read more

Serological testing of paired (i.e. admission and convalescent) sera from 103 fever patients in Kathmandu, Nepal, was performed to estimate the prevalence rates of scrub typhus, murine typhus, Leptospira and dengue virus antibodies and to determine their role in the cause of active infections. Blood cultures from 15 patients grew Salmonella enterica serovar Typhi, 8 grew S. Paratyphi A and 6 grew other bacteria. Diagnostic antibody levels were detected against murine typhus (27/103; 26%), scrub typhus (23/103; 22%), Leptospira (10/103; 10%) and dengue virus (8/103; 8%). Nineteen patients (18%) had diagnostically raised antibodies to more than one infectious agent. Seven S. Typhi (7/15; 47%) and two S. Paratyphi A (2/8; 25%) patients had significant scrub typhus, murine typhus, Leptospira or dengue virus IgM antibody titres. This study confirms the presence of leptospiral, rickettsial and dengue infections in Kathmandu as well as evidence for mixed infections with S. Typhi and Orientia tsutsugamushi or Rickettsia typhi. These infections should be kept in mind when considering the differential diagnoses of fever and empirical treatment options in Nepal. Many patients demonstrated static IgM antibody results between paired serum collections, suggesting recent rather than acutely active infections.

Imwong M, Nair S, Pukrittayakamee S, Sudimack D, Williams JT, Mayxay M, Newton PN, Kim JR, Nandy A, Osorio L et al. 2007. Contrasting genetic structure in Plasmodium vivax populations from Asia and South America. Int J Parasitol, 37 (8-9), pp. 1013-1022. | Citations: 110 (Web of Science Lite) | Show Abstract | Read more

Populations of Plasmodium falciparum show striking differences in linkage disequilibrium, population differentiation and diversity, but only fragmentary data exists on the genetic structure of Plasmodium vivax. We genotyped nine tandem repeat loci bearing 2-8 bp motifs from 345 P. vivax infections collected from three Asian countries and from five locations in Colombia. We observed 9-37 alleles per locus and high diversity (He=0.72-0.79, mean=0.75) in all countries. Numbers of multiple clone infections varied considerably: these were rare in Colombia and India, but > 60% of isolates carried multiple alleles in at least one locus in Thailand and Laos. However, only one or two of the nine loci show >1 allele in many samples, suggesting that mutation within infections may result in overestimation of true multiple carriage rates. Identical nine-locus genotypes were frequently found in Colombian populations, contributing to strong linkage disequilibrium. These identical genotypes were strongly clustered in time, consistent with epidemic transmission of clones and subsequent breakdown of allelic associations, suggesting high rates of inbreeding and low effective recombination rates in this country. In contrast, identical genotypes were rare and loci were randomly associated in all three Asian populations, consistent with higher rates of outcrossing and recombination. We observed low but significant differentiation between different Asian countries (standardized FST = 0.13-0.45). In comparison, we see greater differentiation between collection locations within Colombia (standardized FST = 0.4-0.7), and strong differentiation between continents (standardized FST = 0.48-0.79). The observed heterogeneity in multiple clone carriage rates, linkage disequilibrium and population differentiation are similar in some, but not all, respects to those observed in P. falciparum, and have important implications for the design of association mapping studies, and interpretation of P. vivax epidemiology.

Kelly S, Reed J, Kramer S, Ellis L, Webb H, Sunter J, Salje J, Marinsek N, Gull K, Wickstead B, Carrington M. 2007. Functional genomics in Trypanosoma brucei: a collection of vectors for the expression of tagged proteins from endogenous and ectopic gene loci. Mol Biochem Parasitol, 154 (1), pp. 103-109. | Citations: 115 (Web of Science Lite) | Read more

Dondorp AM, Day NPJ. 2007. The treatment of severe malaria. Trans R Soc Trop Med Hyg, 101 (7), pp. 633-634. | Citations: 24 (Scopus) | Show Abstract | Read more

In the SEAQUAMAT trial, parenteral artesunate was shown to be associated with a considerably lower mortality than quinine, and is now the recommended treatment for severe malaria in low-transmission areas and in the second and third trimesters of pregnancy. A trial is underway to establish its role in African children. The development of artesunate suppositories may provide the means to treat patients with severe disease in remote rural settings, potentially buying the time needed to reach a health care facility. The increasing availability of basic intensive care facilities in developing countries also has the potential to further reduce mortality.

Wangroongsarb P, Chanket T, Gunlabun K, Long DH, Satheanmethakul P, Jetanadee S, Thaipadungpanit J, Wuthiekanun V, Peacock SJ, Blacksell SD et al. 2007. Molecular typing of Leptospira spp. based on putative O-antigen polymerase gene (wzy), the benefit over 16S rRNA gene sequence. FEMS Microbiol Lett, 271 (2), pp. 170-179. | Citations: 9 (Scopus) | Show Abstract | Read more

Molecular typing of leptospiral strains based on variation within putative O-antigen polymerase gene (wzy) was determined among reference strains and those isolated from patients. Using the PCR primers designed from the flanking gene of wzy derived from Leptospira interrogans serovar Copenhageni, all L. interrogans serovars as well as human and rodent leptospiral isolates from Thailand could be amplified. The size of PCR product ranged from 1 to 1.5 kb. The limitation of these primer pairs was the inability to amplify those strains whose sequences differ in the region of the primers, these included Leptospira biflexa (serovar Patoc), Leptospira borgpetersenii (serovar Tarassovi) and Leptospira kirschneri (serovar Bim, Bulgarica, Butembo). Notably, amplification was not limited to L. interrogans as demonstrated by the amplification of some strains from L. kirschneri, Leptospira meyeri, Leptospira noguchii, Leptospira santarosai, L. borgpetersenii and Leptospira weilii. The phylogenetic tree of wzy sequence, inferred by posterior probability of the Bayesian, enabled the categorization of leptospiral serovars into seven genetically related group, of which its differentiation power was better than that of the more highly conserved 16S rRNA gene, which is used extensively for genotyping.

Wiersinga WJ, Dessing MC, Kager PA, Cheng AC, Limmathurotsakul D, Day NP, Dondorp AM, van der Poll T, Peacock SJ. 2007. High-throughput mRNA profiling characterizes the expression of inflammatory molecules in sepsis caused by Burkholderia pseudomallei. Infect Immun, 75 (6), pp. 3074-3079. | Citations: 38 (Scopus) | Show Abstract | Read more

Sepsis is characterized by an uncontrolled inflammatory response to invading microorganisms. We describe the inflammatory mRNA profiles in whole-blood leukocytes, monocytes, and granulocytes using a multigene system for 35 inflammatory markers that included pro- and anti-inflammatory cytokines, chemokines, and signal transduction molecules in a case-control study with 34 patients with sepsis caused by the gram-negative bacterium Burkholderia pseudomallei (the pathogen causing melioidosis) and 32 healthy volunteers. Relative to healthy controls, patients with sepsis showed increased transcription of a whole array of inflammatory genes in peripheral blood leukocytes, granulocytes, and monocytes. Specific monocyte and granulocyte mRNA profiles were identified. Strong correlations were found between inflammatory mRNA expression levels in monocytes and clinical outcome. These data underline the notion that circulating leukocytes are an important source for inflammatory mediators in patients with gram-negative sepsis. Gene profiling such as was done here provides an excellent tool to obtain insight into the extent of inflammation activation in patients with severe infection.

White RG, Ben SC, Kedhar A, Orroth KK, Biraro S, Baggaley RF, Whitworth J, Korenromp EL, Ghani A, Boily M-C, Hayes RJ. 2007. Quantifying HIV-1 transmission due to contaminated injections. Proc Natl Acad Sci U S A, 104 (23), pp. 9794-9799. | Citations: 21 (Scopus) | Show Abstract | Read more

Assessments of the importance of different routes of HIV-1 (HIV) transmission are vital for prioritization of control efforts. Lack of consistent direct data and large uncertainty in the risk of HIV transmission from HIV-contaminated injections has made quantifying the proportion of transmission caused by contaminated injections in sub-Saharan Africa difficult and unavoidably subjective. Depending on the risk assumed, estimates have ranged from 2.5% to 30% or more. We present a method based on an age-structured transmission model that allows the relative contribution of HIV-contaminated injections, and other routes of HIV transmission, to be robustly estimated, both fully quantifying and substantially reducing the associated uncertainty. To do this, we adopt a Bayesian perspective, and show how prior beliefs regarding the safety of injections and the proportion of HIV incidence due to contaminated injections should, in many cases, be substantially modified in light of age-stratified incidence and injection data, resulting in improved (posterior) estimates. Applying the method to data from rural southwest Uganda, we show that the highest estimates of the proportion of incidence due to injections are reduced from 15.5% (95% credible interval) (0.7%, 44.9%) to 5.2% (0.5%, 17.0%) if random mixing is assumed, and from 14.6% (0.7%, 42.5%) to 11.8% (1.2%, 32.5%) under assortative mixing. Lower, and more widely accepted, estimates remain largely unchanged, between 1% and 3% (0.1-6.3%). Although important uncertainty remains, our analysis shows that in rural Uganda, contaminated injections are unlikely to account for a large proportion of HIV incidence. This result is likely to be generalizable to many other populations in sub-Saharan Africa.

Jay A, Dhanda J, Chiodini PL, Woodrow CJ, Farthing PM, Evans J, Jager HR. 2007. Oral cysticercosis British Journal of Oral and Maxillofacial Surgery, 45 (4), pp. 331-334. | Read more

Lindegardh N, Davies GR, Hien TT, Farrar J, Singhasivanon P, Day NPJ, White NJ. 2007. Importance of collection tube during clinical studies of oseltamivir. Antimicrob Agents Chemother, 51 (5), pp. 1835-1836. | Citations: 23 (Scopus) | Show Abstract | Read more

Ex vivo conversion of the anti-influenza drug oseltamivir to its active metabolite can be inhibited by the esterase inhibitor dichlorvos or by using commercial fluoride-oxalate tubes. Oseltamivir and its active metabolite remain intact in plasma samples during a proposed virus heat inactivation step: incubation at 60 degrees C for 45 min.

Chapman SJ, Vannberg FO, Khor CC, Segal S, Moore CE, Knox K, Day NP, Davies RJO, Crook DW, Hill AVS. 2007. Functional polymorphisms in the FCN2 gene are not associated with invasive pneumococcal disease. Mol Immunol, 44 (12), pp. 3267-3270. | Citations: 35 (Scopus) | Show Abstract | Read more

L-ficolin is a pattern-recognition molecule which binds lipoteichoic acid and Gram-positive bacteria and activates the lectin pathway of complement. Five common functional polymorphisms have recently been identified in the FCN2 gene which encodes L-ficolin: three promoter polymorphisms (at positions -986, -602 and -4) which affect serum L-ficolin concentration, and two non-synonymous polymorphisms (Thr236Met and Ala258Ser) which influence carbohydrate binding. We studied the frequencies of these polymorphisms in individuals with invasive pneumococcal disease (IPD) and a control group. Although the five FCN2 polymorphisms were each present in the UK Caucasian population studied, no significant associations were observed between the FCN2 polymorphisms and susceptibility to IPD. This is in contrast to mannose-binding lectin deficiency, which we have previously shown to be associated with increased susceptibility to IPD. Although we are unable to exclude small effects of FCN2 genetic variation on susceptibility to IPD, the result suggests that L-ficolin may not be critical for host defence against pneumococcal infection.

Paris DH, Jenjaroen K, Blacksell SD, Rattanaphone P, Newton PN, Turner GD, Day NP. 2007. Differential patterns of endothelial activation in 'typhus-like' illness TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 189-189.

Mytton OT, McGready R, Lee SJ, Roberts CH, Ashley EA, Carrara VI, Thwai KL, Jay MP, Wiangambun T, Singhasivanon P, Nosten F. 2007. Safety of benzyl benzoate lotion and permethrin in pregnancy: a retrospective matched cohort study. BJOG, 114 (5), pp. 582-587. | Citations: 31 (Scopus) | Show Abstract | Read more

OBJECTIVE: To assess the safety of benzyl benzoate lotion (BBL) and permethrin, topical treatments for scabies, during pregnancy. DESIGN: A retrospective controlled cohort study. POPULATION: Refugee and migrant women attending antenatal clinics (ANC) on the Thai-Burmese border between August 1993 and April 2006. METHODS: Women treated with either BBL (25%) or permethrin (4%) were identified from a manual search of antenatal records. Each case of scabies was matched with four scabies-free controls for gravidity, age, smoking status, malaria, period of treatment and gestational age at treatment. Conditional Poisson regression was used to estimate risk ratios for outcomes of pregnancy (proportion of abortions, congenital abnormalities, neonatal deaths, stillbirths and premature babies), mean birthweight and estimated median gestational age, for scabies and scabies-free women, independently for BBL and permethrin. RESULTS: There were no statistically significant differences in pregnancy outcomes between women who were treated with either BBL (n = 444) compared with their matched controls (n = 1,776) or permethrin (n = 196) treated women and their matched controls (n = 784). Overall, only 10.9% (n = 66) of treatments were in the first trimester. Retreatment rates were higher with BBL 16.4%, than permethrin 9.7%, P = 0.038. Scabies was more common during cooler periods. CONCLUSION: We found no evidence of adverse effects on pregnancy outcome due to topical 25% BBL or 4% permethrin.

Rijken M, Boel M, Barends M, Lindegardh N, McGready R, Nosten F. 2007. Dihydroartemisinin - piperaquine rescue treatment of multidrug-resistant Plasmodium falciparum malaria in pregnancy: a preliminary report TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 34-34.

Barends M, Jaidee A, Brockman A, Sriprawat K, Anderson T, Singhasivanon P, Nosten F. 2007. Twelve year surveillance of Plasmodium falciparum in vitro drug susceptibility on the Thai-Burmese border TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 70-70.

Dondorp AM. 2007. The treatment of severe malaria TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 21-21.

Paris D, Imwong M, Faiz M, Hasan M, Bin Yunus E, Silamut K, Lee S, Day N, Dondorp A. 2007. Loop-mediated isothermal PCR (LAMP) for the diagnosis of falciparum malaria TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 129-129.

Mahavanakul W, Limmathurotsakul D, Teerawattanasuk N, Peacock SJ. 2007. Invasive Erysipelothrix rhusiopathiae infection in northeast Thailand. Southeast Asian J Trop Med Public Health, 38 (3), pp. 478-481. | Citations: 3 (Scopus) | Show Abstract

Three cases of invasive Erysipelothrix rhusipathiae infection, which is considered rare, presented to a hospital in Ubon Ratchathani, northeast Thailand during 2006. Patients presented with variable clinical manifestations including diffused cutaneous lesions, bacteremia and endocarditis. Erysipelothrix infection may be an emerging infection in immunocompromized individuals in Thailand.

Stone SP, Cooper BS, Kibbler CC, Cookson BD, Roberts JA, Medley GF, Duckworth G, Lai R, Ebrahim S, Brown EM et al. 2007. The ORION statement: guidelines for transparent reporting of outbreak reports and intervention studies of nosocomial infection. J Antimicrob Chemother, 59 (5), pp. 833-840. | Citations: 74 (Scopus) | Show Abstract | Read more

The quality of research in hospital epidemiology (infection control) must be improved to be robust enough to influence policy and practice. In order to raise the standards of research and publication, a CONSORT equivalent for these largely quasi-experimental studies has been prepared by the authors of two relevant systematic reviews, following consultation with learned societies, editors of journals and researchers. It consists of a 22 item checklist, and a summary table. The emphasis is on transparency to improve the quality of reporting and on the use of appropriate statistical techniques. The statement has been endorsed by a number of professional special interest groups and societies. Like CONSORT, ORION should be considered a 'work in progress', which requires ongoing dialogue for successful promotion and dissemination. The statement is therefore offered for further public discussion. Journals and research councils are strongly recommended to incorporate it into their submission and reviewing processes. Feedback to the authors is encouraged and the statement will be revised in 2 years.

Hasugian AR, Purba HLE, Kenangalem E, Wuwung RM, Ebsworth EP, Maristela R, Penttinen PMP, Laihad F, Anstey NM, Tjitra E, Price RN. 2007. Dihydroartemisinin-piperaquine versus artesunate-amodiaquine: superior efficacy and posttreatment prophylaxis against multidrug-resistant Plasmodium falciparum and Plasmodium vivax malaria. Clin Infect Dis, 44 (8), pp. 1067-1074. | Citations: 110 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Antimalarial drug resistance is now well established in both Plasmodium falciparum and Plasmodium vivax. In southern Papua, Indonesia, where both strains of plasmodia coexist, we have been conducting a series of studies to optimize treatment strategies. METHODS: We conducted a randomized trial that compared the efficacy and safety of dihydroartemisinin-piperaquine (DHP) with artesunate-amodiaquine (AAQ). The primary end point was the overall cumulative parasitological failure rate at day 42. RESULTS: Of the 334 patients in the evaluable patient population, 185 were infected with P. falciparum, 80 were infected with P. vivax, and 69 were infected with both species. The overall parasitological failure rate at day 42 was 45% (95% confidence interval [CI], 36%-53%) for AAQ and 13% (95% CI, 7.2%-19%) for DHP (hazard ratio [HR], 4.3; 95% CI, 2.5-7.2; P<.001). Rates of both recrudescence of P. falciparum infection and recurrence of P. vivax infection were significantly higher after receipt of AAQ than after receipt of DHP (HR, 3.4 [95% CI, 1.2-9.4] and 4.3 [95% CI, 2.2-8.2], respectively; P<.001). By the end of the study, AAQ recipients were 2.95-fold (95% CI, 1.2- to 4.9-fold) more likely to be anemic and 14.5-fold (95% CI, 3.4- to 61-fold) more likely to have carried P. vivax gametocytes. CONCLUSIONS: DHP was more effective and better tolerated than AAQ against multidrug-resistant P. falciparum and P. vivax infections. The prolonged therapeutic effect of piperaquine delayed the time to P. falciparum reinfection, decreased the rate of recurrence of P. vivax infection, and reduced the risk of P. vivax gametocyte carriage and anemia.

Molyneux M. 2007. UK doctors are already put off by changes in training. BMJ, 334 (7596), pp. 709-710. | Citations: 2 (European Pubmed Central) | Read more

Imwong M, Snounou G, Pukrittayakamee S, Tanomsing N, Kim JR, Nandy A, Guthmann J-P, Nosten F, Carlton J, Looareesuwan S et al. 2007. Relapses of Plasmodium vivax infection usually result from activation of heterologous hypnozoites. J Infect Dis, 195 (7), pp. 927-933. | Citations: 179 (Scopus) | Show Abstract | Read more

BACKGROUND: Relapses originating from hypnozoites are characteristic of Plasmodium vivax infections. Thus, reappearance of parasitemia after treatment can result from relapse, recrudescence, or reinfection. It has been assumed that parasites causing relapse would be a subset of the parasites that caused the primary infection. METHODS: Paired samples were collected before initiation of antimalarial treatment and at recurrence of parasitemia from 149 patients with vivax malaria in Thailand (n=36), where reinfection could be excluded, and during field studies in Myanmar (n=75) and India (n=38). RESULTS: Combined genetic data from 2 genotyping approaches showed that novel P. vivax populations were present in the majority of patients with recurrent infection (107 [72%] of 149 patients overall [78% of patients in Thailand, 75% of patients in Myanmar {Burma}, and 63% of patients in India]). In 61% of the Thai and Burmese patients and in 55% of the Indian patients, the recurrent infections contained none of the parasite genotypes that caused the acute infection. CONCLUSIONS: The P. vivax populations emerging from hypnozoites commonly differ from the populations that caused the acute episode. Activation of heterologous hypnozoite populations is the most common cause of first relapse in patients with vivax malaria.

Khor CC, Chapman SJ, Vannberg FO, Dunne A, Murphy C, Ling EY, Frodsham AJ, Walley AJ, Kyrieleis O, Khan A et al. 2007. A Mal functional variant is associated with protection against invasive pneumococcal disease, bacteremia, malaria and tuberculosis. Nat Genet, 39 (4), pp. 523-528. | Citations: 323 (Scopus) | Show Abstract | Read more

Toll-like receptors (TLRs) and members of their signaling pathway are important in the initiation of the innate immune response to a wide variety of pathogens. The adaptor protein Mal (also known as TIRAP), encoded by TIRAP (MIM 606252), mediates downstream signaling of TLR2 and TLR4 (refs. 4-6). We report a case-control study of 6,106 individuals from the UK, Vietnam and several African countries with invasive pneumococcal disease, bacteremia, malaria and tuberculosis. We genotyped 33 SNPs, including rs8177374, which encodes a leucine substitution at Ser180 of Mal. We found that heterozygous carriage of this variant associated independently with all four infectious diseases in the different study populations. Combining the study groups, we found substantial support for a protective effect of S180L heterozygosity against these infectious diseases (N = 6,106; overall P = 9.6 x 10(-8)). We found that the Mal S180L variant attenuated TLR2 signal transduction.

Wuthiekanun V, Chierakul W, Limmathurotsakul D, Smythe LD, Symonds ML, Dohnt MF, Slack AT, Limpaiboon R, Suputtamongkol Y, White NJ et al. 2007. Optimization of culture of Leptospira from humans with leptospirosis. J Clin Microbiol, 45 (4), pp. 1363-1365. | Citations: 34 (Web of Science Lite) | Show Abstract | Read more

A prospective study of 989 patients with acute febrile illness was performed in northeast Thailand to define the yield of Leptospira from four different types of blood sample. Based on a comparison of the yields from whole blood, surface plasma, deposit from spun plasma, and clotted blood samples from 80 patients with culture-proven leptospirosis, we suggest a sampling strategy in which culture is performed using whole blood and deposit from spun plasma.

Medana IM, Day NP, Hien TT, Mai NTH, Bethell D, Phu NH, Turner GD, Farrar J, White NJ, Esiri MM. 2007. Cerebral calpain in fatal falciparum malaria. Neuropathol Appl Neurobiol, 33 (2), pp. 179-192. | Citations: 10 (Scopus) | Show Abstract | Read more

Disruption of axonal transport may represent a final common pathway leading to neurological dysfunction in cerebral malaria (CM). Calpains are calcium (Ca2+)-activated cysteine proteases which have been implicated in axonal injury in neurological diseases of various aetiologies. In this study we examined the association between mu- and m-calpain, the specific inhibitor calpastatin, and axonal injury in post mortem brain tissue from patients who died from severe malaria. Calpains were associated with axons labelled for the beta-amyloid precursor protein that detects impaired axonal transport. Elevated levels of calpastatin were rarely observed in injured axons. There were increased numbers of neurones with mu-calpain in the nuclear compartment in severe malaria cases compared with non-neurological controls, and increased numbers of glia with nuclear mu-calpain in CM patients compared with non-CM malaria cases and non-neurological controls. There was marked redistribution of calpastatin in the sequestered Plasmodium falciparum-infected erythrocytes. Responses specific to malaria infection were ascertained following analysis of brain samples from fatal cases with acute axonal injury, HIV encephalitis, and progressive multifocal leucoencephalopathy. Our findings implicate a role for calpains in the modulation of disease progression in CM.

Mayxay M, Pongvongsa T, Phompida S, Phetsouvanh R, White NJ, Newton PN. 2007. Diagnosis and management of malaria by rural community health providers in the Lao People's Democratic Republic (Laos). Trop Med Int Health, 12 (4), pp. 540-546. | Citations: 13 (Web of Science Lite) | Show Abstract | Read more

We assessed the knowledge of malaria diagnosis and management by community health providers in rural Vientiane and Savannakhet Provinces, Lao PDR. Sixty health providers (17 pharmacy owners/drug sellers and 43 village health volunteers) were interviewed. All diagnosed malaria using symptoms and signs only; 14% were aware of >2 criteria for the diagnosis of severe malaria. Although chloroquine and quinine, the then recommended Lao national policy for uncomplicated malaria treatment, were the most common antimalarials prescribed - 65% gave incorrect doses and 70% did not know the side effects. Although not recommended by the then national policy, 27% of the health providers used combinations of antimalarials as they considered monotherapy ineffective. This study strongly suggests that further training of Lao rural health providers in malaria diagnosis and management is needed to improve the quality of health services in areas remote from district hospitals.

De Fost M, Chierakul W, Limpaiboon R, Dondorp A, White NJ, van Der Poll T. 2007. Release of granzymes and chemokines in Thai patients with leptospirosis. Clin Microbiol Infect, 13 (4), pp. 433-436. | Citations: 16 (Web of Science Lite) | Show Abstract | Read more

The plasma concentrations of granzymes are considered to reflect the involvement of cytotoxic T-cells and natural killer cells in various disease states. Interferon (IFN)-gamma-inducible protein-10 (IP-10) and monokine induced by IFN-gamma (Mig) are members of the non-ELR CXC chemokine family that act on T-cells and natural killer cells. This study revealed that the plasma concentrations of granzyme B (but not granzyme A), IP-10 and Mig were higher in 44 Thai patients with definite or possible leptospirosis than in healthy blood donors. These data suggest that activation of cell-mediated immunity is part of the early host response to leptospirosis.

Ratcliff A, Siswantoro H, Kenangalem E, Wuwung M, Brockman A, Edstein MD, Laihad F, Ebsworth EP, Anstey NM, Tjitra E, Price RN. 2007. Therapeutic response of multidrug-resistant Plasmodium falciparum and P. vivax to chloroquine and sulfadoxine-pyrimethamine in southern Papua, Indonesia. Trans R Soc Trop Med Hyg, 101 (4), pp. 351-359. | Citations: 108 (Scopus) | Show Abstract | Read more

To determine the level of antimalarial drug resistance in southern Papua, Indonesia, we assessed the therapeutic efficacy of chloroquine plus sulfadoxine-pyrimethamine (CQ+SP) for Plasmodium falciparum infections as well as CQ monotherapy for P. vivax infections. Patients with P. falciparum failing therapy were re-treated with unsupervised quinine+/-doxycycline therapy and those with P. vivax with either unsupervised quinine+/-doxycycline or amodiaquine. In total, 143 patients were enrolled in the study (103 treated with CQ+SP and 40 with CQ). Early treatment failures occurred in four patients (4%) with P. falciparum and six patients (15%) with P. vivax. The failure rate by Day 28 for P. vivax was 65% (95% CI 49-81). After PCR correction for re-infections, the Day 42 recrudescence rate for P. falciparum infections was 48% (95% CI 31-65). Re-treatment with unsupervised quinine+/-doxycycline resulted in further recurrence of malaria in 48% (95% CI 31-65) of P. falciparum infections and 70% (95% CI 37-100) of P. vivax infections. Eleven patients with recurrent P. vivax were re-treated with amodiaquine; there were no early or late treatment failures. In southern Papua, a high prevalence of drug resistance of P. falciparum and P. vivax exists both to first- and second-line therapies. Preliminary data indicate that amodiaquine retains superior efficacy compared with CQ for CQ-resistant P. vivax.

Stone SP, Cooper BS, Kibbler CC, Cookson BD, Roberts JA, Medley GF, Duckworth G, Lai R, Ebrahim S, Brown EM et al. 2007. The ORION statement: guidelines for transparent reporting of outbreak reports and intervention studies of nosocomial infection. Lancet Infect Dis, 7 (4), pp. 282-288. | Citations: 156 (Scopus) | Show Abstract | Read more

The quality of research in hospital epidemiology (infection control) must be improved to be robust enough to influence policy and practice. In order to raise the standards of research and publication, a CONSORT equivalent for these largely quasi-experimental studies has been prepared by the authors of two relevant systematic reviews, following consultation with learned societies, editors of journals, and researchers. The ORION (Outbreak Reports and Intervention Studies Of Nosocomial infection) statement consists of a 22 item checklist, and a summary table. The emphasis is on transparency to improve the quality of reporting and on the use of appropriate statistical techniques. The statement has been endorsed by a number of professional special interest groups and societies. Like CONSORT, ORION should be considered a "work in progress", which requires ongoing dialogue for successful promotion and dissemination. The statement is therefore offered for further public discussion. Journals and research councils are strongly recommended to incorporate it into their submission and reviewing processes. Feedback to the authors is encouraged and the statement will be revised in 2 years.

Tiyawisutsri R, Holden MTG, Tumapa S, Rengpipat S, Clarke SR, Foster SJ, Nierman WC, Day NPJ, Peacock SJ. 2007. Burkholderia Hep_Hag autotransporter (BuHA) proteins elicit a strong antibody response during experimental glanders but not human melioidosis. BMC Microbiol, 7 (1), pp. 19. | Citations: 32 (Scopus) | Show Abstract | Read more

BACKGROUND: The bacterial biothreat agents Burkholderia mallei and Burkholderia pseudomallei are the cause of glanders and melioidosis, respectively. Genomic and epidemiological studies have shown that B. mallei is a recently emerged, host restricted clone of B. pseudomallei. RESULTS: Using bacteriophage-mediated immunoscreening we identified genes expressed in vivo during experimental equine glanders infection. A family of immunodominant antigens were identified that share protein domain architectures with hemagglutinins and invasins. These have been designated Burkholderia Hep_Hag autotransporter (BuHA) proteins. A total of 110/207 positive clones (53%) of a B. mallei expression library screened with sera from two infected horses belonged to this family. This contrasted with 6/189 positive clones (3%) of a B. pseudomallei expression library screened with serum from 21 patients with culture-proven melioidosis. CONCLUSION: Members of the BuHA proteins are found in other Gram-negative bacteria and have been shown to have important roles related to virulence. Compared with other bacterial species, the genomes of both B. mallei and B. pseudomallei contain a relative abundance of this family of proteins. The domain structures of these proteins suggest that they function as multimeric surface proteins that modulate interactions of the cell with the host and environment. Their effect on the cellular immune response to B. mallei and their potential as diagnostics for glanders requires further study.

Ratcliff A, Siswantoro H, Kenangalem E, Maristela R, Wuwung RM, Laihad F, Ebsworth EP, Anstey NM, Tjitra E, Price RN. 2007. Two fixed-dose artemisinin combinations for drug-resistant falciparum and vivax malaria in Papua, Indonesia: an open-label randomised comparison. Lancet, 369 (9563), pp. 757-765. | Citations: 182 (Scopus) | Show Abstract | Read more

BACKGROUND: The burden of Plasmodium vivax infections has been underappreciated, especially in southeast Asia where chloroquine resistant strains have emerged. Our aim was to compare the safety and efficacy of dihydroartemisinin-piperaquine with that of artemether-lumefantrine in patients with uncomplicated malaria caused by multidrug-resistant P falciparum and P vivax. METHODS: 774 patients in southern Papua, Indonesia, with slide-confirmed malaria were randomly assigned to receive either artemether-lumefantrine or dihydroartemisinin-piperaquine and followed up for at least 42 days. The primary endpoint was the overall cumulative risk of parasitological failure at day 42 with a modified intention-to-treat analysis. This trial is registered with, trial number 00157833. FINDINGS: Of the 754 evaluable patients enrolled, 466 had infections with P falciparum, 175 with P vivax, and 113 with a mixture of both species. The overall risk of failure at day 42 was 43% (95% CI 38-48) for artemether-lumefantrine and 19% (14-23) for dihydroartemisinin-piperaquine (hazard ratio=3.0, 95% CI 2.2-4.1, p<0.0001). After correcting for reinfections, the risk of recrudescence of P falciparum was 4.4% (2.6-6.2) with no difference between regimens. Recurrence of vivax occurred in 38% (33-44) of patients given artemether-lumefantrine compared with 10% (6.9-14.0) given dihydroartemisinin-piperaquine (p<0.0001). At the end of the study, patients receiving dihydroartemisinin-piperaquine were 2.0 times (1.2-3.6) less likely to be anaemic and 6.6 times (2.8-16) less likely to carry vivax gametocytes than were those given artemether-lumefantrine. INTERPRETATION: Both dihydroartemisinin-piperaquine and artemether-lumefantrine were safe and effective for the treatment of multidrug-resistant uncomplicated malaria. However, dihydroartemisinin-piperaquine provided greater post-treatment prophylaxis than did artemether-lumefantrine, reducing P falciparum reinfections and P vivax recurrences, the clinical public-health importance of which should not be ignored.

Newton PN, Green MD, Fernandez F. 2007. Counterfeit artemisinin derivatives and Africa: update from authors. PLoS Med, 4 (3), pp. e139. | Citations: 6 (European Pubmed Central) | Read more

Blacksell SD, Myint KSA, Khounsy S, Phruaravanh M, Mammen MP, Day NPJ, Newton PN. 2007. Prevalence of hepatitis E virus antibodies in pigs: implications for human infections in village-based subsistence pig farming in the Lao PDR. Trans R Soc Trop Med Hyg, 101 (3), pp. 305-307. | Citations: 21 (Web of Science Lite) | Show Abstract | Read more

We report a high seroprevalence of hepatitis E virus (HEV) in pigs in the Lao PDR. HEV seroprevalence was 51.2% (300/586) amongst abattoir pigs and 15.3% (46/301) amongst village pigs. The age distribution suggested previous in-village HEV pig infections. These findings suggest a zoonotic risk associated with village-based smallholder pig farming.

Mayxay M, Taylor AM, Khanthavong M, Keola S, Pongvongsa T, Phompida S, Phetsouvanh R, White NJ, Newton PN. 2007. Thiamin deficiency and uncomplicated falciparum malaria in Laos. Trop Med Int Health, 12 (3), pp. 363-369. | Citations: 19 (Scopus) | Show Abstract | Read more

OBJECTIVE: Thiamin deficiency complicates severe Plasmodium falciparum malaria in Thailand and may contribute to acidosis. We therefore estimated the frequency of biochemical thiamin deficiency in patients presenting with uncomplicated falciparum malaria in southern Laos. METHODS: Red cell transketolase activation coefficients (alpha) were measured in 310 patients presenting with uncomplicated falciparum malaria and 42 days after starting treatment. RESULTS: Twelve per cent of patients had biochemical evidence of severe deficiency (alpha values >1.31) at presentation, declining to 3% 42 days later. CONCLUSION: Thiamin deficiency was common in Lao patients admitted with uncomplicated P. falciparum infection and was reduced following treatment of malaria and multivitamin supplementation. The role of this preventable and treatable disorder in malaria and other acute infections, and the incidence of beriberi in rural Laos, needs further investigation.

Nyadong L, Green MD, De Jesus VR, Newton PN, Fernández FM. 2007. Reactive desorption electrospray ionization linear ion trap mass spectrometry of latest-generation counterfeit antimalarials via noncovalent complex formation. Anal Chem, 79 (5), pp. 2150-2157. | Citations: 124 (Scopus) | Show Abstract | Read more

Desorption electrospray ionization mass spectrometry (DESI MS) is rapidly becoming accepted as a powerful surface characterization tool for a wide variety of samples in the open air. Besides its well-established high-throughput capabilities, a unique feature of DESI is that chemical reactions between the charged spray microdroplets and surface molecules can be exploited to enhance ionization. Here, we present a rapid screening assay for artesunate antimalarials based on reactive DESI. Artesunate is a vital therapy for Plasmodium falciparum malaria, but artesunate tablets have been counterfeited on a very large scale in SE Asia, and more recently in Africa. For this reason, faster and more sensitive screening tests are urgently needed. The proposed DESI assay is based on the formation of stable noncovalent complexes between linear alkylamines dissolved in the DESI spray solution and artesunate molecules exposed on the tablet surface. We found that, depending on amine type and concentration, a sensitivity gain of up to 170x can be obtained, in comparison to reagent-less DESI. Hexylamine (Hex), dodecylamine (DDA), and octadecylamine (ODA) produced proton-bound noncovalent complexes with gas-phase stabilities, increasing in the order [M + Hex + H]+ < [M + DDA + H]+ < [M + ODA + H]+. Tandem MS experiments revealed that complex formation occurred by hydrogen bonding between the amine nitrogen and the ether-like moieties within the artesunate lactone ring. After the reactive DESI assay was fully characterized, it was applied to a set of recently collected suspicious artesunate tablets purchased in shops and pharmacies in SE Asia. Not only did we find that these samples were counterfeits, but we also detected the presence of several wrong active ingredients. Of particular concern was the positive detection of artesunate traces in the surface of one of the samples, which we quantified with standard chromatographic techniques.

Thwaites GE, Macmullen-Price J, Tran THC, Pham PM, Nguyen TD, Simmons CP, White NJ, Tran TH, Summers D, Farrar JJ. 2007. Serial MRI to determine the effect of dexamethasone on the cerebral pathology of tuberculous meningitis: an observational study. Lancet Neurol, 6 (3), pp. 230-236. | Citations: 111 (Scopus) | Show Abstract | Read more

BACKGROUND: Adjunctive dexamethasone increases survival from tuberculous meningitis, but the underlying mechanism is unclear. We aimed to determine the effect of dexamethasone on cerebral MRI changes and their association with intracerebral inflammatory responses and clinical outcome in adults treated for tuberculous meningitis. METHODS: Cerebral MRI was undertaken, when possible, at diagnosis and after 60 days and 270 days of treatment in adults with tuberculous meningitis admitted to two hospitals in Vietnam. Patients were randomly assigned either dexamethasone (n=24) or placebo (n=19) and received 9 months of treatment with standard first-line antituberculosis drugs. We assessed associations between MRI findings, treatment allocation, and resolution of fever, coma, cerebrospinal fluid inflammation, and neurological outcome. FINDINGS: 83 scans were done for 43 patients: 19 given placebo, 24 given dexamethasone. Basal meningeal enhancement (82%) and hydrocephalus (77%) were the most common presenting findings. Fewer patients had hydrocephalus after 60 days of treatment with dexamethasone than after placebo treatment (p=0.217). Tuberculomas developed in 74% of patients during treatment and in equal proportions in the treatment groups; they were associated with long-term fever, but not relapse or poor clinical outcome. The basal ganglia were the most common site of infarction; the proportion with infarction after 60 days was halved in the dexamethasone group (27%vs 58%, p=0.130). INTERPRETATION: Dexamethasone may affect outcome from tuberculous meningitis by reducing hydrocephalus and preventing infarction. The effect may have been under-estimated because the most severe patients could not be scanned.

Brouwer AE, van Kan HJM, Johnson E, Rajanuwong A, Teparrukkul P, Wuthiekanun V, Chierakul W, Day N, Harrison TS. 2007. Oral versus intravenous flucytosine in patients with human immunodeficiency virus-associated cryptococcal meningitis. Antimicrob Agents Chemother, 51 (3), pp. 1038-1042. | Citations: 34 (Scopus) | Show Abstract | Read more

In a randomized controlled trial of amphotericin B-based therapy for human immunodeficiency virus (HIV)-associated cryptococcal meningitis in Thailand, we also compared the mycological efficacy, toxicity, and pharmacokinetics of oral versus intravenous flucytosine at 100 mg/kg of body weight/day for the initial 2 weeks. Half of 32 patients assigned to the two arms containing flucytosine were randomized to oral and half to intravenous flucytosine. Early fungicidal activity was determined from serial quantitative cultures of cerebrospinal fluid (CSF), and toxicity was assessed by clinical and laboratory monitoring. Flucytosine and fluorouracil concentrations in plasma and CSF were measured by high-performance liquid chromatography. No significant bone marrow or hepatotoxicity was seen, there was no detectable difference in bone marrow toxicity between patients on intravenous and those on oral formulation, and no patients discontinued treatment. In patients receiving intravenous flucytosine, the median 24-h area under the concentration-time curve was significantly higher than in the oral group. Despite this difference, there was no difference in early fungicidal activity between patients on intravenous compared with patients on oral flucytosine. The results suggest that either formulation can be used safely at this dosage in a developing country setting, without drug concentration monitoring. The bioavailability of the oral formulation may be reduced in late-stage HIV-infected patients in Thailand. Concentrations of flucytosine with intravenous formulation at 100 mg/kg/day may be in excess of those required for maximal fungicidal activity.

Anstey NM, Handojo T, Pain MCF, Kenangalem E, Tjitra E, Price RN, Maguire GP. 2007. Lung injury in vivax malaria: pathophysiological evidence for pulmonary vascular sequestration and posttreatment alveolar-capillary inflammation. J Infect Dis, 195 (4), pp. 589-596. | Citations: 131 (Scopus) | Show Abstract | Read more

BACKGROUND: The mechanisms underlying lung injury in vivax malaria are not well understood. Inflammatory responses to Plasmodium falciparum and P. vivax, to our knowledge, have not previously been compared at an organ level. METHODS: Respiratory symptoms and physiological aspects were measured longitudinally in Indonesian adults with uncomplicated vivax (n=50) and falciparum (n=50) malaria. Normal values were derived from 109 control subjects. Gas transfer was partitioned into its alveolar-capillary membrane (D(M)) and pulmonary capillary vascular (V(C)) components, to characterize the site and timing of impaired gas transfer. RESULTS: Mean baseline V(C) volume was significantly reduced in vivax and falciparum malaria, improving with treatment in each species. Baseline D(M) function was not impaired in either species. The progressive deterioration in D(M) function after treatment was statistically significant in vivax malaria but not in uncomplicated falciparum malaria. Oxygen saturation deteriorated after treatment in vivax but improved in falciparum malaria. CONCLUSIONS: The baseline reduction in V(C) volume but not in D(M) function suggests encroachment on V(C) volume by parasitized erythrocytes and suggests that P. vivax-infected erythrocytes may sequester within the pulmonary microvasculature. Progressive alveolar-capillary dysfunction after treatment of vivax malaria is consistent with a greater inflammatory response to a given parasite burden in P. vivax relative to that in P. falciparum.

Nguyen-Pouplin J, Tran H, Tran H, Phan TA, Dolecek C, Farrar J, Tran TH, Caron P, Bodo B, Grellier P. 2007. Antimalarial and cytotoxic activities of ethnopharmacologically selected medicinal plants from South Vietnam. J Ethnopharmacol, 109 (3), pp. 417-427. | Citations: 64 (Scopus) | Show Abstract | Read more

Malaria is a major global public health problem and the alarming spread of drug resistance and limited number of effective drugs now available underline how important it is to discover new antimalarial compounds. An ethnopharmacological investigation was undertaken of medicinal plants traditionally used to treat malaria in the South Vietnam. Forty-nine plants were identified, 228 extracts were prepared and tested for their in vitro activity against Plasmodium falciparum, and assessed for any cytotoxicity against the human cancer cell line HeLa and the embryonic lung MRC5 cell line. In a first screening at a concentration of 10 microg/ml, 92 extracts from 46 plants showed antiplasmodial activity (parasite growth inhibition >30%). The IC(50) values of the most active extracts were determined as well as their selectivity towards Plasmodium falciparum in comparison to their cytotoxic effects against the human cell lines. Six plants showed interesting antiplasmodial activity (IC(50) ranging from 0.4 to 8.6 microg/ml) with a good selectivity: two Menispermaceae, Arcangelisia flava (L.) Merr. and Fibraurea tinctoria Lour., and also Harrisonia perforata (Blanco) Merr. (Simaroubaceae), Irvingia malayana Oliv. ex Benn. (Irvingiaceae), Elaeocarpus kontumensis Gagn. (Elaeocarpaceae) and Anneslea fragrans Wall. (Theaceae).

Ashley EA, Stepniewska K, Lindegårdh N, McGready R, Annerberg A, Hutagalung R, Singtoroj T, Hla G, Brockman A, Proux S et al. 2007. Pharmacokinetic study of artemether-lumefantrine given once daily for the treatment of uncomplicated multidrug-resistant falciparum malaria. Trop Med Int Health, 12 (2), pp. 201-208. | Citations: 65 (Scopus) | Show Abstract | Read more

BACKGROUND: Adherence to antimalarial drug regimens is improved by simple dosing. If the fixed antimalarial drug combination artemether-lumefantrine (AL) could be given once daily, this should improve adherence and thus effectiveness and lower the risk of selecting for resistance. METHODS: In an open randomized study, 43 patients with uncomplicated falciparum malaria were given equivalent doses of AL with 200 ml flavoured milk either as the conventional twice-daily regimen or as a single daily dose for 3 days. The primary end point was a comparison of the areas under the plasma lumefantrine concentration-time curves (AUC). Secondary end points were the day 42 polymerase chain reaction (PCR)-adjusted cure rates and the tolerability profiles. RESULTS: Lumefantrine pharmacokinetic profiles were obtained for 36 patients. The AUC((0-->infinity)) of the once-daily regimen was 30% lower than that in the conventional regimen (P = 0.011) with a median (range) value of 306 (114-5781) microg/ml h, compared with 432 (308-992) microg/ml h. There was no significant difference in the peak plasma concentrations reached. PCR-adjusted cure rate estimates at day 42 of follow-up were 94% (95% CI: 84-100) in the six-dose arm and 85% (70-100) in the three-dose arm (P = 0.3). CONCLUSION: Artemether-lumefantrine efficacy is reduced by once-daily dosing, because absorption of lumefantrine is dose limited. At currently recommended doses, this antimalarial should be given twice daily in a 3-day regimen, with food containing fat.

de Veij M, Vandenabeele P, Hall KA, Fernandez FM, Green MD, White NJ, Dondorp AM, Newton PN, Moens L. 2007. Fast detection and identification of counterfeit antimalarial tablets by Raman spectroscopy JOURNAL OF RAMAN SPECTROSCOPY, 38 (2), pp. 181-187. | Citations: 64 (Scopus) | Show Abstract | Read more

During the last decade there has been an apparent increase in the prevalence of counterfeit medicines in developing as well as developed countries. The pivotal antimalarial artesunate has been counterfeited on a large scale in SE Asia. In this work, the possibilities of Raman spectroscopy are explored as a fast and reliable screening method for the detection of counterfeit artesunate tablets. In this study, 50 'artesunate tablets', purchased in SE Asia, were examined. This spectroscopic method was able to distinguish between genuine and counterfeit artesunate and to identify the composition of the counterfeit tablets. These contained no detectable levels of artesunate, but consisted mostly of starch, calcite (CaCO 3 ), and paracetamol (4-acetamidophenol). In one particular case an admixture of rutile (TiO 2 ) and artesunate was detected. The results of the investigation by Raman spectroscopy were in agreement with those of colorimetric tests and of liquid chromatography-mass spectrometry on the artesunate. Moreover, principal components analysis (PCA) was combined with hierarchical cluster analysis to establish an automated approach for the discrimination between different groups of counterfeits and genuine artesunate tablets. These results demonstrate that Raman spectroscopy combined with multivariate analysis is a promising and reliable methodology for the fast characterization of genuine and counterfeit artesunate antimalarial tablets. Copyright © 2006 John Wiley & Sons, Ltd.

Chantratita N, Wuthiekanun V, Boonbumrung K, Tiyawisutsri R, Vesaratchavest M, Limmathurotsakul D, Chierakul W, Wongratanacheewin S, Pukritiyakamee S, White NJ et al. 2007. Biological relevance of colony morphology and phenotypic switching by Burkholderia pseudomallei. J Bacteriol, 189 (3), pp. 807-817. | Citations: 88 (Scopus) | Show Abstract | Read more

Melioidosis is a notoriously protracted illness and is difficult to cure. We hypothesize that the causative organism, Burkholderia pseudomallei, undergoes a process of adaptation involving altered expression of surface determinants which facilitates persistence in vivo and that this is reflected by changes in colony morphology. A colony morphotyping scheme and typing algorithm were developed using clinical B. pseudomallei isolates. Morphotypes were divided into seven types (denoted I to VII). Type I gave rise to other morphotypes (most commonly type II or III) by a process of switching in response to environmental stress, including starvation, iron limitation, and growth at 42 degrees C. Switching was associated with complex shifts in phenotype, one of which (type I to type II) was associated with a marked increase in production of factors putatively associated with in vivo concealment. Isogenic types II and III, derived from type I, were examined using several experimental models. Switching between isogenic morphotypes occurred in a mouse model, where type II appeared to become adapted for persistence in a low-virulence state. Isogenic type II demonstrated a significant increase in intracellular replication fitness compared with parental type I after uptake by epithelial cells in vitro. Isogenic type III demonstrated a higher replication fitness following uptake by macrophages in vitro, which was associated with a switch to type II. Mixed B. pseudomallei morphologies were common in individual clinical specimens and were significantly more frequent in samples of blood, pus, and respiratory secretions than in urine and surface swabs. These findings have major implications for therapeutics and vaccine development.

McGready R, Kaveri SV, Lacroix-Desmazes S, Krudsood S, Newton PN. 2007. Acquired haemophilia A in early pregnancy associated with Plasmodium vivax malaria and hyperthyroidism. Aust N Z J Obstet Gynaecol, 47 (1), pp. 76-77. | Citations: 2 (Web of Science Lite) | Read more

Ashley EA, Stepniewska K, Lindegårdh N, Annerberg A, Kham A, Brockman A, Singhasivanon P, White NJ, Nosten F. 2007. How much fat is necessary to optimize lumefantrine oral bioavailability? Trop Med Int Health, 12 (2), pp. 195-200. | Citations: 99 (Scopus) | Show Abstract | Read more

BACKGROUND: Artemether-lumefantrine (AL) is the only fixed, artemisinin-based combination antimalarial drug which is registered internationally and deployed on a large scale. Absorption of the hydrophobic lipophilic lumefantrine component varies widely between individuals and is greatly increased by fat coadministration; but patients with acute malaria are frequently nauseated and anorexic, making dietary advice difficult to comply with. The aim of this study was to describe the dose-response relationship between coadministration of fat and relative lumefantrine bioavailability, in order to determine the minimum amount of fat necessary to optimize absorption. METHOD: We conducted a multiple crossover pharmacokinetic study in 12 healthy volunteers. This compared the area under the plasma concentration-time curve (AUC) for lumefantrine after administration of a single dose of AL in the fasting state given with 0, 10, 40, 150 and 500 ml of soya milk corresponding to 0, 0.32, 1.28, 4.8 and 16 g of fat. All volumes of milk supplements were tested in all subjects with a 3- to 4-week washout period in-between. RESULTS: A dose-response relationship was demonstrated between the volume of soya milk administered and lumefantrine bioavailability. AL administration with soya milk increased the lumefantrine AUC more than five fold. The population mean estimated volume of soya milk required to obtain 90% of maximum effect (in terms of lumefantrine AUC) was 36 ml (corresponding to 1.2 g of fat). CONCLUSIONS: Coadministration of artemether-lumefantrine with a relatively small amount of fat (as soya milk) was required to ensure maximum absorption of lumefantrine in healthy adult volunteers.

Desai M, ter Kuile FO, Nosten F, McGready R, Asamoa K, Brabin B, Newman RD. 2007. Epidemiology and burden of malaria in pregnancy. Lancet Infect Dis, 7 (2), pp. 93-104. | Citations: 682 (Scopus) | Show Abstract | Read more

We reviewed evidence of the clinical implications and burden of malaria in pregnancy. Most studies come from sub-Saharan Africa, where approximately 25 million pregnant women are at risk of Plasmodium falciparum infection every year, and one in four women have evidence of placental infection at the time of delivery. P falciparum infections during pregnancy in Africa rarely result in fever and therefore remain undetected and untreated. Meta-analyses of intervention trials suggest that successful prevention of these infections reduces the risk of severe maternal anaemia by 38%, low birthweight by 43%, and perinatal mortality by 27% among paucigravidae. Low birthweight associated with malaria in pregnancy is estimated to result in 100,000 infant deaths in Africa each year. Although paucigravidae are most affected by malaria, the consequences for infants born to multigravid women in Africa may be greater than previously appreciated. This is because HIV increases the risk of malaria and its adverse effects, particularly in multigravidae, and recent observational studies show that placental infection almost doubles the risk of malaria infection and morbidity in infants born to multigravidae. Outside Africa, malaria infection rates in pregnant women are much lower but are more likely to cause severe disease, preterm births, and fetal loss. Plasmodium vivax is common in Asia and the Americas and, unlike P falciparum, does not cytoadhere in the placenta, yet, is associated with maternal anaemia and low birthweight. The effect of infection in the first trimester, and the longer term effects of malaria beyond infancy, are largely unknown and may be substantial. Better estimates are also needed of the effects of malaria in pregnancy outside Africa, and on maternal morbidity and mortality in Africa. Global risk maps will allow better estimation of potential impact of successful control of malaria in pregnancy.

Mayxay M, Barends M, Brockman A, Jaidee A, Nair S, Sudimack D, Pongvongsa T, Phompida S, Phetsouvanh R, Anderson T et al. 2007. In vitro antimalarial drug susceptibility and pfcrt mutation among fresh Plasmodium falciparum isolates from the Lao PDR (Laos). Am J Trop Med Hyg, 76 (2), pp. 245-250. | Citations: 16 (Scopus) | Show Abstract | Read more

Recent drug trials in Laos have shown high levels of Plasmodium falciparum resistance to chloroquine, but there are no published data on in vitro antimalarial drug susceptibility. We used the double-site enzyme-linked pLDH immunodetection (DELI) assay to estimate the in vitro antimalarial drug susceptibility of 108 fresh P. falciparum isolates from southern Laos. The geometric mean (95% confidence interval) 50% inhibitory concentration values (nmol/L) were 152.4 (123.8-187.6) for chloroquine, 679.8 (533.8-863.0) for quinine, 45.9 (37.9-55.7) for mefloquine, 5.0 (4.4-6.4) for artesunate, 6.3 (4.5-8.9) for dihydroartemisinin, and 59.1 (46.4-75.3) for lumefantrine. The proportion of isolates defined as resistant were 65%, 40%, and 8% for chloroquine, quinine, and mefloquine, respectively. Of 53 isolates genotyped for the pfcrt T76K chloroquine-resistance mutation, 48 (91%) were mutants. P. falciparum in Laos is multi-drug resistant; antimalarial immunity resulting from the use of ineffective chloroquine before 2005 probably contributes significantly to the therapeutic responses in clinical trials.

Nair S, Nash D, Sudimack D, Jaidee A, Barends M, Uhlemann A-C, Krishna S, Nosten F, Anderson TJC. 2007. Recurrent gene amplification and soft selective sweeps during evolution of multidrug resistance in malaria parasites. Mol Biol Evol, 24 (2), pp. 562-573. | Citations: 106 (Scopus) | Show Abstract | Read more

When selection is strong and beneficial alleles have a single origin, local reductions in genetic diversity are expected. However, when beneficial alleles have multiple origins or were segregating in the population prior to a change in selection regime, the impact on genetic diversity may be less clear. We describe an example of such a "soft" selective sweep in the malaria parasite Plasmodium falciparum that involves adaptive genome rearrangements. Amplification in copy number of genome regions containing the pfmdr1 gene on chromosome 5 confer resistance to mefloquine and spread rapidly in the 1990s. Using flanking microsatellite data and real-time polymerase chain reaction determination of copy number, we show that 5-15 independent amplification events have occurred in parasites on the Thailand/Burma border. The amplified genome regions (amplicons) range in size from 14.7 to 49 kb and contain 2-11 genes, with 2-4 copies arranged in tandem. To examine the impact of drug selection on flanking variation, we genotyped 48 microsatellites on chromosome 5 in 326 parasites from a single Thai location. Diversity was reduced in a 170- to 250-kb (10-15 cM) region of chromosomes containing multiple copies of pfmdr1, consistent with hitchhiking resulting from the rapid recent spread of selected chromosomes. However, diversity immediately flanking pfmdr1 is reduced by only 42% on chromosomes bearing multiple amplicons relative to chromosomes carrying a single copy. We highlight 2 features of these results: 1) All amplicon break points occur in monomeric A/T tracts (9-45 bp). Given the abundance of these tracts in P. falciparum, we expect that duplications will occur frequently at multiple genomic locations and have been underestimated as drivers of phenotypic evolution in this pathogen. 2) The signature left by the spread of amplified genome segments is broad, but results in only limited reduction in diversity. If such "soft" sweeps are common in nature, statistical methods based on diversity reduction may be inefficient at detecting evidence for selection in genome-wide marker screens. This may be particularly likely when mutation rate is high, as appears to be the case for gene duplications, and in pathogen populations where effective population sizes are typically very large.

Ward SA, Sevene EJP, Hastings IM, Nosten F, McGready R. 2007. Antimalarial drugs and pregnancy: safety, pharmacokinetics, and pharmacovigilance. Lancet Infect Dis, 7 (2), pp. 136-144. | Citations: 119 (Scopus) | Show Abstract | Read more

Before a recommendation for antimalarial drug use in pregnancy is made, it is essential that we understand the potential risks involved and have mechanisms in place to monitor risk during treatment. This requires data on drug disposition during pregnancy and potential toxicological liabilities to the developing fetus and mother. In most cases this information is not available. We review the reproductive toxicology of the main antimalarial drug classes in use or under development. Preclinical data are presented if appropriate, but as human experience overrides such data, in instances in which preclinical studies do not correlate with the human experience the data are reviewed only briefly. Additionally, we highlight the lack of appropriate drug disposition data in pregnancy and suggest mechanisms that can be used to capture data on risk after drug treatment in pregnancy.

Nosten F, McGready R, Mutabingwa T. 2007. Case management of malaria in pregnancy. Lancet Infect Dis, 7 (2), pp. 118-125. | Citations: 60 (Scopus) | Show Abstract | Read more

In all malarious areas, infection by any of the main human plasmodial species during pregnancy is detrimental to the mother and the fetus. These potentially fatal infections must be prevented, but when they develop they require prompt diagnosis and treatment. Current tools to detect malaria parasites in pregnant women are often not used and remain too insensitive to detect a low parasitaemia. The kinetics, safety, and efficacy of available antimalarial drugs are poorly documented because pregnant women are systematically excluded from clinical trials. A considerable effort, involving clinical trials, is urgently required to improve the diagnosis and case management of malaria during pregnancy if the morbidity and mortality of maternal malaria is to be reduced.

Villegas L, McGready R, Htway M, Paw MK, Pimanpanarak M, Arunjerdja R, Viladpai-Nguen SJ, Greenwood B, White NJ, Nosten F. 2007. Chloroquine prophylaxis against vivax malaria in pregnancy: a randomized, double-blind, placebo-controlled trial. Trop Med Int Health, 12 (2), pp. 209-218. | Citations: 47 (Scopus) | Show Abstract | Read more

OBJECTIVE: To assess the safety of chloroquine (CQ) as prophylaxis against Plasmodium vivax infection during pregnancy. METHOD: One thousand pregnant Karen women were enrolled in a randomized, double-blind, placebo-controlled trial of chemoprophylaxis with chloroquine (500 mg phosphate (or 300 mg base) weekly). Women received a median (range) chloroquine phosphate total dose of 9500 (1500-17 500) mg. The mothers were actively followed from inclusion to delivery and their infants until 12 months of age. RESULTS: Chloroquine prophylaxis completely prevented P. vivax episodes; 10.1% (95%CI: 7.3-14.5) of women in the placebo group experienced at least one episode of vivax malaria but no episode occurred in women in the CQ group. By contrast, the numbers of P. falciparum episodes were similar in each group: 7.4% (95%CI: 3.7-11.1) and 5.6% (95%CI: 3.3-7.9) in the placebo and CQ groups respectively (P = 0.56). Chloroquine prophylaxis was well tolerated and there was no difference in the proportions of reported side effects between CQ treated and placebo groups except for the duration of palpitations and sleeping disorders which were more frequent in those who had received CQ. Chloroquine prophylaxis had no impact on maternal anaemia, birth weight, gestational age, development of newborns or on growth, neurological development or visual acuity in infants at 1 year of age. CONCLUSION: Chloroquine is safe and effective as prophylaxis against P. vivax during pregnancy in this population.

Blacksell SD, Bryant NJ, Paris DH, Doust JA, Sakoda Y, Day NPJ. 2007. Scrub typhus serologic testing with the indirect immunofluorescence method as a diagnostic gold standard: a lack of consensus leads to a lot of confusion. Clin Infect Dis, 44 (3), pp. 391-401. | Citations: 110 (Scopus) | Show Abstract | Read more

A review was performed to determine the evidence base for scrub typhus indirect immunofluorescence assay (IFA) methodologies and the criteria for positive results. This review included a total of 109 publications, which comprised 123 eligible studies for analysis (14 publications included 2 substudies). There was considerable underreporting of the IFA methodology and seropositivity criteria used, with most studies using a defined cutoff titer rather than an increase in the titer in paired samples. The choice of positivity cutoff titer varied by country and purpose of the IFA test. This variation limits the comparability of seroprevalence rates between studies and, more seriously, raises questions about the appropriateness of the cutoffs for positive IFA results chosen for diagnosis of acute scrub typhus infection. We suggest that the diagnosis of scrub typhus using IFA should be based on a > or =4-fold increase in the titer in paired serum samples and should only be based on a single sample titer when there is an adequate local evidence base.

Brent AJ, Matthews PC, Dance DA, Pitt TL, Handy R. 2007. Misdiagnosing melioidosis. Emerg Infect Dis, 13 (2), pp. 349-351. | Citations: 14 (Scopus) | Read more

Pitt TL, Trakulsomboon S, Dance DAB. 2007. Recurrent melioidosis: possible role of infection with multiple strains of Burkholderia pseudomallei. J Clin Microbiol, 45 (2), pp. 680-681. | Citations: 11 (Scopus) | Read more

Stepniewska K, Chotivanich K, Brockman A, Day NPJ, White NJ. 2007. Overestimating resistance in field testing of malaria parasites: simple methods for estimating high EC50 values using a Bayesian approach. Malar J, 6 (1), pp. 4. | Citations: 7 (Scopus) | Show Abstract | Read more

Conventional methods of assessing in-vitro antimalarial drug-concentration effect relationships in field testing of fresh isolates assess each parasite isolate individually. This leads to systematic overestimation of EC50 values for the most resistant isolates, and thus overestimation of the degree of resistance. In antimalarial drug-susceptibility studies conducted on the north-western border of Thailand the overestimation of EC50 for the most resistant isolate ranged from 15% for artesunate to 43% for mefloquine. If isolates cannot be stored for re-testing, more accurate estimations of the degree of resistance can be obtained using a Bayesian approach to data analysis which is described here.

Green MD, Nettey H, Villalva Rojas O, Pamanivong C, Khounsaknalath L, Grande Ortiz M, Newton PN, Fernández FM, Vongsack L, Manolin O. 2007. Use of refractometry and colorimetry as field methods to rapidly assess antimalarial drug quality. J Pharm Biomed Anal, 43 (1), pp. 105-110. | Citations: 40 (Scopus) | Show Abstract | Read more

The proliferation of counterfeit and poor-quality drugs is a major public health problem; especially in developing countries lacking adequate resources to effectively monitor their prevalence. Simple and affordable field methods provide a practical means of rapidly monitoring drug quality in circumstances where more advanced techniques are not available. Therefore, we have evaluated refractometry, colorimetry and a technique combining both processes as simple and accurate field assays to rapidly test the quality of the commonly available antimalarial drugs; artesunate, chloroquine, quinine, and sulfadoxine. Method bias, sensitivity, specificity and accuracy relative to high-performance liquid chromatographic (HPLC) analysis of drugs collected in the Lao PDR were assessed for each technique. The HPLC method for each drug was evaluated in terms of assay variability and accuracy. The accuracy of the combined method ranged from 0.96 to 1.00 for artesunate tablets, chloroquine injectables, quinine capsules, and sulfadoxine tablets while the accuracy was 0.78 for enterically coated chloroquine tablets. These techniques provide a generally accurate, yet simple and affordable means to assess drug quality in resource-poor settings.

Golfetto I, McGready R, Ghebremeskel K, Min Y, Dubowitz L, Nosten F, Drury P, Simpson JA, Arunjerdja R, Crawford MA. 2007. Fatty acid composition of milk of refugee Karen and urban Korean mothers. Is the level of DHA in breast milk of Western women compromised by high intake of saturated fat and linoleic acid? Nutr Health, 18 (4), pp. 319-332. | Citations: 4 (Scopus) | Show Abstract | Read more

BACKGROUND: Lower proportions of docosahexaenoic acid (DHA) and total n-3 metabolites have been reported in breast milk of European, Australian and North American women compared with milk of mothers from non-Western countries. This difference is not always explained by intakes of marine products. OBJECTIVE: We investigated the possibility that the relative composition of DHA and total n-3 metabolites in breast milk of non-Western mothers with low fat intakes is higher than the levels commonly reported in their Western counterparts. SUBJECTS: Mature milk of refugee Karen women from two different camps in Thailand (n=26 and n=53), and transition milk from urban Korean mothers (n=12) in Seoul was collected. In common with their respective community, the mothers have low fat intake, which is predominately of plant origin. RESULTS: The percentage levels of DHA and n-3 metabolites in the milk of the Karen mothers were 0.52 +/- 0.14 and 0.85 +/- 0.24 (camp 1) and 0.54 +/- 0.22 and 0.92 +/- 0.42 (camp 2). In the Korean milk, DHA was 0.96 +/- 0.21 and total n-3 metabolites 1.51 +/- 0.3. CONCLUSION: We postulate that the levels of DHA and total n-3 metabolites may be compromised in breast milk of mothers on the Western high fat diet. This calls into question the use of DHA composition of such milk as a reference for the formulation of milk designed, for infant feed or, to test the function of DHA in neuro-visual development.

Uhlemann A-C, McGready R, Ashley EA, Brockman A, Singhasivanon P, Krishna S, White NJ, Nosten F, Price RN. 2007. Intrahost selection of Plasmodium falciparum pfmdr1 alleles after antimalarial treatment on the northwestern border of Thailand. J Infect Dis, 195 (1), pp. 134-141. | Citations: 39 (Scopus) | Show Abstract | Read more

BACKGROUND: Increased pfmdr1 copy number is associated with reduced susceptibility to structurally unrelated antimalarial drugs. We assessed how administration of different antimalarial drugs altered pfmdr1 polymorphism in parasites from patients who experienced treatment failure. METHODS: In studies conducted on the northwestern border of Thailand, amplifications and single-nucleotide polymorphisms in pfmdr1 were compared before and after antimalarial drug treatment. RESULTS: Intrahost changes in pfmdr1 copy number were observed in 20% (26/132) of patients with recurrent infections. Among infections that recrudesced after mefloquine-containing regimens, increases in pfmdr1 copy number occurred in 68% (95% confidence interval [CI], 46%-85%), and decreases occurred in 2% (95% CI, 0.4%-11%) of isolates; corresponding proportions after artemether-lumefantrine were 25% (2/8) and 11% (2/19); after quinine, 50% (1/2) and 40% (4/10); and after artemisinins alone, 0% (0/10) and 19% (3/16) of isolates (overall P<.001). CONCLUSIONS: Intrahost selection based on pfmdr1 copy number occurs frequently in parasite populations within individual patients. Amplification confers multidrug resistance but probably imposes a significant fitness cost to the parasites.

Barends M, Jaidee A, Khaohirun N, Singhasivanon P, Nosten F. 2007. In vitro activity of ferroquine (SSR 97193) against Plasmodium falciparum isolates from the Thai-Burmese border. Malar J, 6 (1), pp. 81. | Citations: 48 (Scopus) | Show Abstract | Read more

BACKGROUND: On the borders of Thailand, Plasmodium falciparum has become resistant to nearly all available drugs, and there is an urgent need to find new antimalarial drugs or drug combinations. Ferroquine (SSR97193) is a new 4-aminoquinoline antimalarial active against chloroquine resistant and sensitive P. falciparum strains in vivo and in vitro. This antimalarial organic iron complex (a ferrocenyl group has been associated with chloroquine) is meant to use the affinity of Plasmodium for iron to increase the probability for encountering the anti-malarial molecule.The aim of the present study was to investigate the activity of ferroquine against P. falciparum isolates from an area with a known high multi-drug resistance rate. METHODS: Parasite isolates were obtained from patients with acute falciparum malaria attending the clinics of SMRU. In vitro cultures of these isolates were set-up in the SMRU-laboratory on pre-dosed drug plates, and grown in culture for 42 hours. Parasite growth was assessed by the double-site enzyme-linked pLDH immunodetection (DELI) assay. RESULTS: Sixty-five P. falciparum isolates were successfully grown in culture. The ferroquine mean IC50 (95% CI) was 9.3 nM (95% C.I.: 8.7 - 10.0). The mean IC50 value for the principal metabolite of ferroquin, SR97213A, was 37.0 nM (95% C.I.: 34.3 - 39.9), which is four times less active than ferroquine. The isolates in this study were highly multi-drug resistant but ferroquine was more active than chloroquine, quinine, mefloquine and piperaquine. Only artesunate was more active than ferroquine. Weak but significant correlations were found between ferroquine and its principal metabolite (r2 = 0.4288), chloroquine (r2 = 0.1107) and lumefantrine (r2 = 0.2364). CONCLUSION: The results presented in this study demonstrate that the new ferroquine compound SSR97193 has high anti-malarial activity in vitro against multi-drug resistant P. falciparum.

Suwanarusk R, Russell B, Chavchich M, Chalfein F, Kenangalem E, Kosaisavee V, Prasetyorini B, Piera KA, Barends M, Brockman A et al. 2007. Chloroquine resistant Plasmodium vivax: in vitro characterisation and association with molecular polymorphisms. PLoS One, 2 (10), pp. e1089. | Citations: 125 (Scopus) | Show Abstract | Read more

BACKGROUND: Treatment failure of chloroquine for P. vivax infections has reached high levels in the eastern provinces of Indonesia, however, in vitro characterization of chloroquine resistance and its associated molecular profile have yet to be determined. METHODS: Using a modified schizont maturation assay we investigated the in vitro chloroquine susceptibility profile and molecular polymorphisms of P. vivax isolates collected from Papua, Indonesia, where high levels of clinical chloroquine treatment failure have been reported, and from Thailand, where chloroquine treatment is generally effective. RESULTS: The geometric mean chloroquine IC(50) for P. vivax isolates from Papua (n = 145) was 312 nM [95%CI: 237-411 nM] compared to 46.8 nM [95%CI: 34.7-63.1 nM] from Thailand (n = 81); p<0.001. Correlating with the known clinical efficacy of the area, a cut off for chloroquine resistance was defined as 220 nM, a level exceeded in 13.6% (11/81) of Thai isolates and 65% (94/145) of Papuan isolates; p<0.001. Several sequence polymorphisms in pvcrt-o and pvmdr1, and difference in pvmdr1 copy number were identified. A Y976F mutation in pvmdr1 was present in 96% (123/128) of Papuan isolates and 25% (17/69) of Thai isolates; p<0.001. Overall, the geometric mean chloroquine IC(50) in isolates with the Y976F mutation was 283 nM [95%CI: 211-379], compared to 44.5 nM [95%CI: 31.3-63.4] in isolates with the wild type; p< 0.001. Pvmdr1 amplification occurred in 23% (15/66) of Thai isolates compared to none (0/104) of Indonesian isolates (p<0.001), but was not associated with increased chloroquine resistance after controlling for geographical location. CONCLUSIONS: In vitro susceptibility testing of P. vivax discriminates between populations with differing levels of clinical efficacy of chloroquine. The pvmdr1 polymorphism at Y976F may provide a useful tool to highlight areas of emerging chloroquine resistance, although further studies defining its clinical correlates are needed.

Larsen RA, Bauer M, Brouwer AE, Sanchez A, Thomas AM, Rajanuwong A, Chierakul W, Peacock SJ, Day N, White NJ et al. 2007. In vitro-clinical correlations for amphotericin B susceptibility in AIDS-associated cryptococcal meningitis. Antimicrob Agents Chemother, 51 (1), pp. 343-345. | Citations: 8 (Web of Science Lite) | Show Abstract | Read more

Reliable measures of antifungal drug susceptibility are needed. We tested the susceptibility of Cryptococcus neoformans from patients treated with amphotericin B. In vitro susceptibility employed a modified broth macrodilution method. We demonstrate a strong correlation between the quantitative measures of in vitro amphotericin B susceptibility and the quantitative response observed in patients.

Ricci C, Nyadong L, Fernandez FM, Newton PN, Kazarian SG. 2007. Combined Fourier-transform infrared imaging and desorption electrospray-ionization linear ion-trap mass spectrometry for analysis of counterfeit antimalarial tablets. Anal Bioanal Chem, 387 (2), pp. 551-559. | Citations: 85 (Scopus) | Show Abstract | Read more

This paper reports use of a combination of Fourier-transform infrared (FTIR) spectroscopic imaging and desorption electrospray ionization linear ion-trap mass spectrometry (DESI MS) for characterization of counterfeit pharmaceutical tablets. The counterfeit artesunate antimalarial tablets were analyzed by both techniques. The results obtained revealed the ability of FTIR imaging in non-destructive micro-attenuated total reflection (ATR) mode to detect the distribution of all components in the tablet, the identities of which were confirmed by DESI MS. Chemical images of the tablets were obtained with high spatial resolution. The FTIR spectroscopic imaging method affords inherent chemical specificity with rapid acquisition of data. DESI MS enables high-sensitivity detection of trace organic compounds. Combination of these two orthogonal surface-characterization methods has great potential for detection and analysis of counterfeit tablets in the open air and without sample preparation.

Kamya MR, Yeka A, Bukirwa H, Lugemwa M, Rwakimari JB, Staedke SG, Talisuna AO, Greenhouse B, Nosten F, Rosenthal PJ et al. 2007. Artemether-lumefantrine versus dihydroartemisinin-piperaquine for treatment of malaria: a randomized trial. PLoS Clin Trials, 2 (5), pp. e20. | Citations: 100 (Scopus) | Show Abstract | Read more

OBJECTIVES: To compare the efficacy and safety of artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) for treating uncomplicated falciparum malaria in Uganda. DESIGN: Randomized single-blinded clinical trial. SETTING: Apac, Uganda, an area of very high malaria transmission intensity. PARTICIPANTS: Children aged 6 mo to 10 y with uncomplicated falciparum malaria. INTERVENTION: Treatment of malaria with AL or DP, each following standard 3-d dosing regimens. OUTCOME MEASURES: Risks of recurrent parasitemia at 28 and 42 d, unadjusted and adjusted by genotyping to distinguish recrudescences and new infections. RESULTS: Of 421 enrolled participants, 417 (99%) completed follow-up. The unadjusted risk of recurrent falciparum parasitemia was significantly lower for participants treated with DP than for those treated with AL after 28 d (11% versus 29%; risk difference [RD] 18%, 95% confidence interval [CI] 11%-26%) and 42 d (43% versus 53%; RD 9.6%, 95% CI 0%-19%) of follow-up. Similarly, the risk of recurrent parasitemia due to possible recrudescence (adjusted by genotyping) was significantly lower for participants treated with DP than for those treated with AL after 28 d (1.9% versus 8.9%; RD 7.0%, 95% CI 2.5%-12%) and 42 d (6.9% versus 16%; RD 9.5%, 95% CI 2.8%-16%). Patients treated with DP had a lower risk of recurrent parasitemia due to non-falciparum species, development of gametocytemia, and higher mean increase in hemoglobin compared to patients treated with AL. Both drugs were well tolerated; serious adverse events were uncommon and unrelated to study drugs. CONCLUSION: DP was superior to AL for reducing the risk of recurrent parasitemia and gametocytemia, and provided improved hemoglobin recovery. DP thus appears to be a good alternative to AL as first-line treatment of uncomplicated malaria in Uganda. To maximize the benefit of artemisinin-based combination therapy in Africa, treatment should be integrated with aggressive strategies to reduce malaria transmission intensity.

Wuthiekanun V, Sirisukkarn N, Daengsupa P, Sakaraserane P, Sangkakam A, Chierakul W, Smythe LD, Symonds ML, Dohnt MF, Slack AT et al. 2007. Clinical diagnosis and geographic distribution of leptospirosis, Thailand. Emerg Infect Dis, 13 (1), pp. 124-126. | Citations: 42 (Scopus) | Show Abstract | Read more

We defined the positive predictive accuracy of a hospital-based clinical diagnosis of leptospirosis in 9 provinces across Thailand. Of 700 suspected cases, 143 (20%) were confirmed by laboratory testing. Accuracy of clinical diagnosis varied from 0% to 50% between the provinces and was highest during the rainy season. Most confirmed cases occurred in the north and northeast regions of the country.

Barnes KI, Lindegardh N, Ogundahunsi O, Olliaro P, Plowe CV, Randrianarivelojosia M, Gbotosho GO, Watkins WM, Sibley CH, White NJ. 2007. World Antimalarial Resistance Network (WARN) IV: clinical pharmacology. Malar J, 6 (1), pp. 122. | Citations: 39 (Scopus) | Show Abstract | Read more

A World Antimalarial Resistance Network (WARN) database has the potential to improve the treatment of malaria, through informing current drug selection and use and providing a prompt warning of when treatment policies need changing. This manuscript outlines the contribution and structure of the clinical pharmacology component of this database. The determinants of treatment response are multi-factorial, but clearly providing adequate blood concentrations is pivotal to curing malaria. The ability of available antimalarial pharmacokinetic data to inform optimal dosing is constrained by the small number of patients studied, with even fewer (if any) studies conducted in the most vulnerable populations. There are even less data relating blood concentration data to the therapeutic response (pharmacodynamics). By pooling all available pharmacokinetic data, while paying careful attention to the analytical methodologies used, the limitations of small (and thus underpowered) individual studies may be overcome and factors that contribute to inter-individual variability in pharmacokinetic parameters defined. Key variables for pharmacokinetic studies are defined in terms of patient (or study subject) characteristics, the formulation and route of administration of the antimalarial studied, the sampling and assay methodology, and the approach taken to data analysis. Better defining these information needs and criteria of acceptability of pharmacokinetic-pharmacodynamic (PK-PD) studies should contribute to improving the quantity, relevance and quality of these studies. A better understanding of the pharmacokinetic properties of antimalarials and a more clear definition of what constitutes "therapeutic drug levels" would allow more precise use of the term "antimalarial resistance", as it would indicate when treatment failure is not caused by intrinsic parasite resistance but is instead the result of inadequate drug levels. The clinical pharmacology component of the WARN database can play a pivotal role in monitoring accurately for true antimalarial drug resistance and promptly correcting sub-optimal dosage regimens to prevent these contributing to the emergence and spread of antimalarial resistance.

Chantratita N, Wuthiekanun V, Thanwisai A, Limmathurotsakul D, Cheng AC, Chierakul W, Day NPJ, Peacock SJ. 2007. Accuracy of enzyme-linked immunosorbent assay using crude and purified antigens for serodiagnosis of melioidosis. Clin Vaccine Immunol, 14 (1), pp. 110-113. | Citations: 36 (Scopus) | Show Abstract | Read more

Five enzyme-linked immunosorbent assays developed to detect antibodies to different Burkholderia pseudomallei antigen preparations were evaluated as diagnostic tests for melioidosis in northeast Thailand. The highest diagnostic indices were observed for an affinity-purified antigen (sensitivity, 82%; specificity, 72%) and crude B. pseudomallei antigen (sensitivity, 81%; specificity, 70%), an improvement over the indirect hemagglutination assay (sensitivity, 73%; specificity, 64%).

Heiny AT, Miotto O, Srinivasan KN, Khan AM, Zhang GL, Brusic V, Tan TW, August JT. 2007. Evolutionarily conserved protein sequences of influenza a viruses, avian and human, as vaccine targets. PLoS One, 2 (11), pp. e1190. | Citations: 121 (Scopus) | Show Abstract | Read more

BACKGROUND: Influenza A viruses generate an extreme genetic diversity through point mutation and gene segment exchange, resulting in many new strains that emerge from the animal reservoirs, among which was the recent highly pathogenic H5N1 virus. This genetic diversity also endows these viruses with a dynamic adaptability to their habitats, one result being the rapid selection of genomic variants that resist the immune responses of infected hosts. With the possibility of an influenza A pandemic, a critical need is a vaccine that will recognize and protect against any influenza A pathogen. One feasible approach is a vaccine containing conserved immunogenic protein sequences that represent the genotypic diversity of all current and future avian and human influenza viruses as an alternative to current vaccines that address only the known circulating virus strains. METHODOLOGY/PRINCIPAL FINDINGS: Methodologies for large-scale analysis of the evolutionary variability of the influenza A virus proteins recorded in public databases were developed and used to elucidate the amino acid sequence diversity and conservation of 36,343 sequences of the 11 viral proteins of the recorded virus isolates of the past 30 years. Technologies were also applied to identify the conserved amino acid sequences from isolates of the past decade, and to evaluate the predicted human lymphocyte antigen (HLA) supertype-restricted class I and II T-cell epitopes of the conserved sequences. Fifty-five (55) sequences of 9 or more amino acids of the polymerases (PB2, PB1, and PA), nucleoprotein (NP), and matrix 1 (M1) proteins were completely conserved in at least 80%, many in 95 to 100%, of the avian and human influenza A virus isolates despite the marked evolutionary variability of the viruses. Almost all (50) of these conserved sequences contained putative supertype HLA class I or class II epitopes as predicted by 4 peptide-HLA binding algorithms. Additionally, data of the Immune Epitope Database (IEDB) include 29 experimentally identified HLA class I and II T-cell epitopes present in 14 of the conserved sequences. CONCLUSIONS/SIGNIFICANCE: This study of all reported influenza A virus protein sequences, avian and human, has identified 55 highly conserved sequences, most of which are predicted to have immune relevance as T-cell epitopes. This is a necessary first step in the design and analysis of a polyepitope, pan-influenza A vaccine. In addition to the application described herein, these technologies can be applied to other pathogens and to other therapeutic modalities designed to attack DNA, RNA, or protein sequences critical to pathogen function.

Pandit A, Arjyal A, Day JN, Paudyal B, Dangol S, Zimmerman MD, Yadav B, Stepniewska K, Campbell JI, Dolecek C et al. 2007. An open randomized comparison of gatifloxacin versus cefixime for the treatment of uncomplicated enteric fever. PLoS One, 2 (6), pp. e542. | Citations: 52 (Scopus) | Show Abstract | Read more

OBJECTIVE: To assess the efficacy of gatifloxacin versus cefixime in the treatment of uncomplicated culture positive enteric fever. DESIGN: A randomized, open-label, active control trial with two parallel arms. SETTING: Emergency Room and Outpatient Clinics in Patan Hospital, Lagankhel, Lalitpur, Nepal. PARTICIPANTS: Patients with clinically diagnosed uncomplicated enteric fever meeting the inclusion criteria. INTERVENTIONS: Patients were allocated to receive one of two drugs, Gatifloxacin or Cefixime. The dosages used were Gatifloxacin 10 mg/kg, given once daily for 7 days, or Cefixime 20 mg/kg/day given in two divided doses for 7 days. OUTCOME MEASURES: The primary outcome measure was fever clearance time. The secondary outcome measure was overall treatment failure (acute treatment failure and relapse). RESULTS: Randomization was carried out in 390 patients before enrollment was suspended on the advice of the independent data safety monitoring board due to significant differences in both primary and secondary outcome measures in the two arms and the attainment of a priori defined endpoints. Median (95% confidence interval) fever clearance times were 92 hours (84-114 hours) for gatifloxacin recipients and 138 hours (105-164 hours) for cefixime-treated patients (Hazard Ratio[95%CI] = 2.171 [1.545-3.051], p<0.0001). 19 out of 70 (27%) patients who completed the 7 day trial had acute clinical failure in the cefixime group as compared to 1 out of 88 patients (1%) in gatifloxacin group(Odds Ratio [95%CI] = 0.031 [0.004 - 0.237], p<0.001). Overall treatment failure patients (relapsed patients plus acute treatment failure patients plus death) numbered 29. They were determined to be (95% confidence interval) 37.6 % (27.14%-50.2%) in the cefixime group and 3.5% (2.2%-11.5%) in the gatifloxacin group (HR[95%CI] = 0.084 [0.025-0.280], p<0.0001). There was one death in the cefixime group. CONCLUSIONS: Based on this study, gatifloxacin is a better treatment for uncomplicated enteric fever as compared to cefixime. TRIAL REGISTRATION: Current Controlled Trials ISRCTN75784880.

Chotivanich K, Silamut K, Day NPJ. 2007. Laboratory diagnosis of malaria infection - A short review of methods New Zealand Journal of Medical Laboratory Science, 61 (1), pp. 4-7. | Citations: 13 (Scopus) | Show Abstract

Malaria is one of the most important tropical infectious diseases. The incidence of malaria worldwide is estimated to be 300-500 million clinical cases each year with a mortality of between one and three million people worldwide annually. The accurate and timely diagnosis of malaria infection is essential if severe complications and mortality are to be reduced by early specific antimalarial treatment. This review details the methods for the laboratory diagnosis of malaria infection.

Nguyen THM, Tran THC, Thwaites G, Ly VC, Dinh XS, Ho Dang TN, Dang QT, Nguyen DP, Nguyen HP, To SD et al. 2007. Dexamethasone in Vietnamese adolescents and adults with bacterial meningitis. N Engl J Med, 357 (24), pp. 2431-2440. | Citations: 149 (Scopus) | Show Abstract | Read more

BACKGROUND: It is uncertain whether all adults with bacterial meningitis benefit from treatment with adjunctive dexamethasone. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of dexamethasone in 435 patients over the age of 14 years who had suspected bacterial meningitis. The goal was to determine whether dexamethasone reduced the risk of death at 1 month and the risk of death or disability at 6 months. RESULTS: A total of 217 patients were assigned to the dexamethasone group, and 218 to the placebo group. Bacterial meningitis was confirmed in 300 patients (69.0%), probable meningitis was diagnosed in 123 patients (28.3%), and an alternative diagnosis was made in 12 patients (2.8%). An intention-to-treat analysis of all the patients showed that dexamethasone was not associated with a significant reduction in the risk of death at 1 month (relative risk, 0.79; 95% confidence interval [CI], 0.45 to 1.39) or the risk of death or disability at 6 months (odds ratio, 0.74; 95% CI, 0.47 to 1.17). In patients with confirmed bacterial meningitis, however, there was a significant reduction in the risk of death at 1 month (relative risk, 0.43; 95% CI, 0.20 to 0.94) and in the risk of death or disability at 6 months (odds ratio, 0.56; 95% CI, 0.32 to 0.98). These effects were not found in patients with probable bacterial meningitis. Results of multivariate analysis indicated that dexamethasone treatment for patients with probable bacterial meningitis was significantly associated with an increased risk of death at 1 month, an observation that may be explained by cases of tuberculous meningitis in the treatment group. CONCLUSIONS: Dexamethasone does not improve the outcome in all adolescents and adults with suspected bacterial meningitis; a beneficial effect appears to be confined to patients with microbiologically proven disease, including those who have received prior treatment with antibiotics. (Current Controlled Trials number, ISRCTN42986828 [] .).

Green MD, Nettey H, Rojas OV, Pamanivong C, Khounsaknalath L, Ortiz MG, Newton PN, Fernández FM, Vongsack L, Manolin O. 2007. Corrigendum to “Use of refractometry and colorimetry as field methods to rapidly assess antimalarial drug quality” [J. Pharm. Biomed. Anal. 43 (2007) 105–110] Journal of Pharmaceutical and Biomedical Analysis, 43 (5), pp. 1890-1890. | Citations: 1 (Scopus) | Read more

Slesak G, Phanthavong P, Rasphone O, Luangxay K, Anoulakkham P, Pahatsalang V, Soumphonphakdy B, White JA, Newton PN. 2007. Obstructive biliary ascariasis with cholangitis and hepatic abscesses in Laos: a case report with gall bladder ultrasound video. J Infect, 54 (4), pp. e233-e235. | Citations: 7 (Scopus) | Show Abstract | Read more

A 12-year-old Lao boy with obstructive biliary Ascaris infection is described and video of the gallbladder ultrasound presented. The patient developed severe complications of obstructive cholangitis, a large right pleural effusion and hepatic abscesses requiring prolonged antibiotic therapy. The differential diagnosis of worms in the gall-bladder is discussed.

Mayxay M, Khomthilat T, Souvannasing P, Phounesavath K, Vorasane B, Keomany S, Douangdala P, Philavong K, Srour L, Newton PN. 2007. Factors associated with a measles outbreak in children admitted at Mahosot Hospital, Vientiane, Laos. BMC Public Health, 7 (1), pp. 193. | Citations: 5 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: In 2002 and 2003 there were large outbreaks of measles in many provinces of Laos, including in Vientiane. We therefore conducted a study to determine risk factors associated with measles amongst children admitted at Mahosot Hospital, Vientiane. METHODS: A retrospective case-control study was conducted in 50 children with clinical measles who were matched by age and sex with 50 healthy children (who had never had a febrile rash) living in the same villages as the cases. RESULTS: The proportion of children with complete immunizations was significantly lower in the group with clinical measles compared to the controls [13/50 (26%) vs 34/50 (68%), P < 0.001). The percentage of children who had received measles vaccine at 9-23 months of age was significantly lower in the group with clinical measles compared to the healthy controls [12/50 (24%) vs 24/50 (48%), P = 0.01). The family educational and socio-economic status did not differ significantly (P > 0.05) between cases and controls. CONCLUSION: These results emphasize the importance of intensification of measles immunization coverage in Laos. The strengthening of campaigns with large, widespread high second dose coverage is likely to be a key measure to prevent further measles outbreaks in Laos (192 words).

Luksameetanasan R, Blacksell SD, Kalambaheti T, Wuthiekanun V, Chierakul W, Chueasuwanchai S, Apiwattanaporn A, Stenos J, Graves S, Peacock SJ, Day NPJ. 2007. Patient and sample-related factors that effect the success of in vitro isolation of Orientia tsutsugamushi. Southeast Asian J Trop Med Public Health, 38 (1), pp. 91-96. | Citations: 34 (Scopus) | Show Abstract

Orientia tsutsugamushi is the causative agent of scrub typhus infection, a major cause of human disease in rural areas of Southeast Asia. Twenty-six blood samples collected from patients with serologically proven scrub typhus during a six month period were sent to Bangkok (535 km from the clinical site) by road at ambient temperature (average daily temperature range: 27.1-29.1 degrees C) for attempted in vitro isolation in Vero cells. O. tsutsugamushi was isolated from 12 samples (sensitivity 46.7%) with the time to isolation ranging from 16 to 37 days [median 27 days, inter-quartile range (IQR) 22.5-33.5 days]. Patient factors such as days of fever and O. tsutsugamushi IgM antibody titer, transport factors such as transit time, and isolate genotype (Karp and Gilliam/Kawasaki) were assessed to determine their influence on the outcome of in vitro isolation. None of the factors significantly influenced the isolation outcome. This study demonstrates that O. tsutsugamushi can often be isolated in vitro from the blood of scrub typhus patients when transported at ambient tropical temperatures for many days.

Khounsy S, Gleeson LJ, Van Aken D, Westbury HA, Blacksell SD. 2007. Diagnosis of classical swine fever virus in a limited resource setting: the influence of pig breed on methodology and sample selection. Trop Anim Health Prod, 39 (1), pp. 21-25. | Read more

White NJ, Day NPJ, Dondorp A, Anstey N. 2007. UK recommendations for severe malaria are worrying. BMJ, 334 (7592), pp. 490. | Citations: 1 (European Pubmed Central) | Read more

Lee SWH, Cheah PY, Liong ML, Yuen KH, Schaeffer AJ, Propert K, Krieger JN, Northern Malaysia Prostatitis Study Group, Chronic Prostatitis Collaborative Research Network Group. 2007. Demographic and clinical characteristics of chronic prostatitis: prospective comparison of the University of Sciences Malaysia Cohort with the United States National Institutes of Health Cohort. J Urol, 177 (1), pp. 153-157. | Citations: 16 (Web of Science Lite) | Show Abstract | Read more

PURPOSE: We compared demographic and clinical characteristics of the University of Sciences Malaysia Chronic Prostatitis Cohort to the United States National Institutes of Health Chronic Prostatitis Cohort. MATERIALS AND METHODS: Participants met the same definition of chronic prostatitis/chronic pelvic pain syndrome. Each participant had extensive demographic, medical history, previous treatment, clinical and laboratory evaluations. RESULTS: The University of Sciences Malaysia and National Institutes of Health cohorts proved similar in most respects. National Institutes of Health-Chronic Prostatitis Symptom Index total scores, pain and urinary subscores were similar for the 332 University of Sciences Malaysia Chronic Prostatitis Cohort and 488 National Institutes of Health Chronic Prostatitis Cohort participants. Differences included worse quality of life subscore for the University of Sciences Malaysia Chronic Prostatitis Cohort, differences in the location, number of sites, and types of pain/discomfort between the 2 populations, and that the University of Sciences Malaysia participants had received less previous treatment. CONCLUSIONS: The demographic characteristics and clinical presentation of chronic prostatitis/chronic pelvic pain syndrome proved remarkably similar in these diverse populations. Both cohorts experienced major reduction in their quality of life from chronic pelvic pain and urinary symptoms. Comparison of diverse populations using standard clinical, laboratory and assessment instruments is feasible, and may provide important insights into chronic prostatitis/chronic pelvic pain syndrome and the factors that determine clinical outcome.

Molyneux M, Marsh K, White N, Farrar J, French N, Day N, Rowland-Jones S. 2007. UK doctors are already put off by changes in training [3] British Medical Journal, 334 (7596), pp. 709-710. | Citations: 1 (Scopus)

Plowe CV, Roper C, Barnwell JW, Happi CT, Joshi HH, Mbacham W, Meshnick SR, Mugittu K, Naidoo I, Price RN et al. 2007. World Antimalarial Resistance Network (WARN) III: molecular markers for drug resistant malaria. Malar J, 6 (1), pp. 121. | Citations: 83 (Scopus) | Show Abstract | Read more

Molecular markers for drug resistant malaria represent public health tools of great but mostly unrealized potential value. A key reason for the failure of molecular resistance markers to live up to their potential is that data on the their prevalence is scattered in disparate databases with no linkage to the clinical, in vitro and pharmacokinetic data that are needed to relate the genetic data to relevant phenotypes. The ongoing replacement of older monotherapies for malaria by new, more effective combination therapies presents an opportunity to create an open access database that brings together standardized data on molecular markers of drug resistant malaria from around the world. This paper presents a rationale for creating a global database of molecular markers for drug resistant malaria and for linking it to similar databases containing results from clinical trials of drug efficacy, in vitro studies of drug susceptibility, and pharmacokinetic studies of antimalarial drugs, in a World Antimalarial Resistance Network (WARN). This database will be a global resource, guiding the selection of first line drugs for treating uncomplicated malaria, for preventing malaria in travelers and for intermittent preventive treatment of malaria in pregnant women, infants and other vulnerable groups. Perhaps most important, a global database for molecular markers of drug resistant malaria will accelerate the identification and validation of markers for resistance to artemisinin-based combination therapies and, thereby, potentially prolong the useful therapeutic lives of these important new drugs.

McBryde ES, Pettitt AN, Cooper BS, McElwain DLS. 2007. Characterizing an outbreak of vancomycin-resistant enterococci using hidden Markov models. J R Soc Interface, 4 (15), pp. 745-754. | Citations: 32 (Scopus) | Show Abstract | Read more

BACKGROUND: Antibiotic-resistant nosocomial pathogens can arise in epidemic clusters or sporadically. Genotyping is commonly used to distinguish epidemic from sporadic vancomycin-resistant enterococci (VRE). We compare this to a statistical method to determine the transmission characteristics of VRE. METHODS AND FINDINGS: A structured continuous-time hidden Markov model (HMM) was developed. The hidden states were the number of VRE-colonized patients (both detected and undetected). The input for this study was weekly point-prevalence data; 157 weeks of VRE prevalence. We estimated two parameters: one to quantify the cross-transmission of VRE and the other to quantify the level of VRE colonization from sporadic sources. We compared the results to those obtained by concomitant genotyping and phenotyping. We estimated that 89% of transmissions were due to ward cross-transmission while 11% were sporadic. Genotyping found that 90% had identical glycopeptide resistance genes and 84% were identical or nearly identical on pulsed-field gel electrophoresis (PFGE). There was some evidence, based on model selection criteria, that the cross-transmission parameter changed throughout the study period. The model that allowed for a change in transmission just prior to the outbreak and again at the peak of the outbreak was superior to other models. This model estimated that cross-transmission increased at week 120 and declined after week 135, coinciding with environmental decontamination. SIGNIFICANCE: We found that HMMs can be applied to serial prevalence data to estimate the characteristics of acquisition of nosocomial pathogens and distinguish between epidemic and sporadic acquisition. This model was able to estimate transmission parameters despite imperfect detection of the organism. The results of this model were validated against PFGE and glycopeptide resistance genotype data and produced very similar results. Additionally, HMMs can provide information about unobserved events such as undetected colonization.

Stone S, Slade R, Fuller C, McAteer J, Cookson B, Teare L, Jeanes A, Cooper B, Roberts J, Duckworth G et al. 2007. Cleanyourhands Campaign: a critique of the critique. J Hosp Infect, 66 (3), pp. 288-289. | Citations: 5 (Scopus) | Read more

McAteer J, Stone S, Roberts J, Michie S, FIT study team, Fuller C, Slade R, Charlett A, Cookson B, Cooper B et al. 2007. Use of performance feedback to increase healthcare worker hand-hygiene behaviour. J Hosp Infect, 66 (3), pp. 291-292. | Citations: 6 (Scopus) | Read more

Stone S, Slade R, Fuller C, Charlett A, Cookson B, Teare L, Jeanes A, Cooper B, Roberts J, Duckworth G et al. 2007. Early communication: does a national campaign to improve hand hygiene in the NHS work? Initial English and Welsh experience from the NOSEC study (National Observational Study to Evaluate the CleanYourHandsCampaign). J Hosp Infect, 66 (3), pp. 293-296. | Citations: 20 (Scopus) | Read more

Cooper BS, Cookson BD, Davey PG, Stone SP. 2007. Introducing the ORION Statement, a CONSORT equivalent for infection control studies. J Hosp Infect, 65 Suppl 2 (SUPPL. 2), pp. 85-87. | Citations: 16 (Scopus) | Read more

Cooper BS. 2007. Confronting models with data. J Hosp Infect, 65 Suppl 2 (SUPPL. 2), pp. 88-92. | Citations: 10 (Scopus) | Show Abstract | Read more

Until now, most of the mathematical modelling work on nosocomial infections has used simple models that have permitted qualitative, but not reliable quantitative predictions about the likely effect of different interventions. Increasingly, researchers would like to use models to provide reliable quantitative answers to both scientific and policy questions. This requires confronting models with data. Here, we discuss the importance of this confrontation with data with reference to previous modelling work, and outline the standard methods for doing this. We then describe a powerful new set of tools that promises to allow us to provide better answers to such questions, making far greater use than current methods of the information content of highly detailed hospital infection datasets. These tools should allow us to address questions that would have been impossible to answer using previous analytical techniques.

Fowler S, Webber A, Cooper BS, Phimister A, Price K, Carter Y, Kibbler CC, Simpson AJH, Stone SP. 2007. Successful use of feedback to improve antibiotic prescribing and reduce Clostridium difficile infection: a controlled interrupted time series. J Antimicrob Chemother, 59 (5), pp. 990-995. | Citations: 123 (Scopus) | Show Abstract | Read more

OBJECTIVES: To investigate the effect of reinforcing a narrow-spectrum antibiotic policy on antibiotic prescription and Clostridium difficile infection (CDI) rates by feedback of antibiotic use to doctors, as part of a departmental audit and feedback programme. DESIGN: A prospective controlled interrupted time-series (ITS) study, with pre-defined pre- and post-intervention periods, each of 21 months. SETTING: Three acute medical wards for elderly people in a teaching hospital. PARTICIPANTS: Six thousand one hundred and twenty-nine consecutive unselected acute medical admissions aged >or=80 years. INTERVENTIONS: A 'narrow-spectrum' antibiotic policy (reinforced by an established programme of audit and feedback of antibiotic usage and CDI rates) was introduced, following an unplanned rise in amoxicillin/clavulanate (Augmentin) use. It targeted broad-spectrum antibiotics for reduction (cephalosporins and amoxicillin/clavulanate) and narrow-spectrum antibiotics for increase (benzyl penicillin, amoxicillin and trimethoprim). Changes in the use of targeted antibiotics (intervention group) were compared with those of untargeted antibiotics (control group) using segmented regression analysis. Changes in CDI rates were examined by the Poisson regression model. Methicillin-resistant Staphylococcus aureus (MRSA) acquisition rates acted as an additional control. RESULTS: There was a reduction in the use of all targeted broad-spectrum antibiotics and an increase in all targeted narrow-spectrum antibiotics, statistically significant for sudden change and/or linear trend. All other antibiotic use remained unchanged. CDI rates fell with incidence rate ratios of 0.35 (0.17, 0.73) (P=0.009). MRSA incidence did not change [0.79 (0.49, 1.28); P=0.32]. CONCLUSIONS: This is the first controlled prospective ITS study to use feedback to reinforce antibiotic policy and reduce CDI. Multicentre ITS or cluster randomized trials of this and other methods need to be undertaken to establish the most effective means of optimizing antibiotic use and reducing CDI.

Breman JG, Alilio MS, White NJ. 2007. Defining and defeating the intolerable burden of Malaria III. Progress and perspectives American Journal of Tropical Medicine and Hygiene, 77 (SUPPL. 6), | Citations: 10 (Scopus)

Breman JG, Alilio MS, White NJ. 2007. Defining and defeating the intolerable burden of malaria III. Progress and perspectives American Journal of Tropical Medicine and Hygiene, 77 (SUPPL. 6), | Citations: 13 (Scopus)

Woodrow CJ, Eziefula AC, Agranoff D, Scott GM, Watson J, Chiodini PL, Lockwood DNJ, Grant AD. 2007. Early risk assessment for viral haemorrhagic fever: Experience at the Hospital for tropical diseases, London, UK Journal of Infection, 54 (1), pp. 6-11. | Read more

Das I, Jumaa P. 2007. Has the severity of Clostridium difficile infections increased? J Hosp Infect, 65 (1), pp. 85-86. | Citations: 1 (European Pubmed Central) | Read more

Porter E, Damani N. 2007. Epidemic meticillin-resistant Staphylococcus aureus strains associated with Northern Ireland. J Hosp Infect, 65 (1), pp. 88-89. | Citations: 1 (European Pubmed Central) | Read more

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