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The pathophysiology of severe falciparum malaria involves a complex interaction between the host, parasite, and gut microbes. In this review, we focus on understanding parasite-induced intestinal injury and changes in the human intestinal microbiota composition in patients with Plasmodium falciparum malaria. During the blood stage of P. falciparum infection, infected red blood cells adhere to the vascular endothelium, leading to widespread microcirculatory obstruction in critical tissues, including the splanchnic vasculature. This process may cause intestinal injury and gut leakage. Epidemiological studies indicate higher rates of concurrent bacteraemia in severe malaria cases. Furthermore, severe malaria patients exhibit alterations in the composition and diversity of the intestinal microbiota, although the exact contribution to pathophysiology remains unclear. Mouse studies have demonstrated that the gut microbiota composition can impact susceptibility to Plasmodium infections. In patients with severe malaria, the microbiota shows an enrichment of pathobionts, including pathogens that are known to cause concomitant bloodstream infections. Microbial metabolites have also been detected in the plasma of severe malaria patients, potentially contributing to metabolic acidosis and other clinical complications. However, establishing causal relationships requires intervention studies targeting the gut microbiota.
\n \n\n \n \nAbstract\n\nBackground\nUncertainty over the therapeutic benefit of parenteral remdesivir in coronavirus disease 2019 (COVID-19) has resulted in varying treatment guidelines.\n\n\nMethods\nIn a multicenter open-label, controlled, adaptive, pharmacometric platform trial, low-risk adult patients with early symptomatic COVID-19 were randomized to 1 of 8 treatment arms including intravenous remdesivir (200 mg followed by 100 mg daily for 5 days) or no study drug. The primary outcome was the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clearance (estimated under a linear model fit to the daily log10 viral densities, days 0\u20137) in standardized duplicate oropharyngeal swab eluates, in a modified intention-to-treat population. This ongoing adaptive trial is registered at ClinicalTrials.gov (NCT05041907).\n\n\nResults\nThe 2 study arms enrolled 131 patients (remdesivir n = 67, no study drug n = 64) and estimated viral clearance rates from a median of 18 swab samples per patient (a total of 2356 quantitative polymerase chain reactions). Under the linear model, compared with the contemporaneous control arm (no study drug), remdesivir accelerated mean estimated viral clearance by 42% (95% credible interval, 18%\u201373%).\n\n\nConclusions\nParenteral remdesivir accelerates viral clearance in early symptomatic COVID-19. Pharmacometric assessment of therapeutics using the method described can determine in vivo clinical antiviral efficacy rapidly and efficiently.\n
\n \n\n \n \nAbstract\nThe emergence and spread of artemisinin resistant Plasmodium falciparum, first in the Greater Mekong Subregion (GMS), and now in East Africa, is a major threat to global malaria eliminations ambitions. To investigate the artemisinin resistance mechanism, transcriptome analysis was conducted of 577 P. falciparum isolates collected in the GMS between 2016\u20132018. A specific artemisinin resistance-associated transcriptional profile was identified that involves a broad but discrete set of biological functions related to proteotoxic stress, host cytoplasm remodeling and REDOX metabolism. The artemisinin resistance-associated transcriptional profile evolved from initial transcriptional responses of susceptible parasites to artemisinin. The genetic basis for this adapted response is likely to be complex.
\n \n\n \n \nBACKGROUND: Antibiotic usage, contact with high transmission healthcare settings as well as changes in immune system function all vary by a patient's age and sex. Yet, most analyses of antimicrobial resistance (AMR) ignore demographic indicators and provide only country-level resistance prevalence values. This study aimed to address this knowledge gap by quantifying how resistance prevalence and incidence of bloodstream infection (BSI) varied by age and sex across bacteria and antibiotics in Europe. METHODS AND FINDINGS: We used patient-level data collected as part of routine surveillance between 2015 and 2019 on BSIs in 29 European countries from the European Antimicrobial Resistance Surveillance Network (EARS-Net). A total of 6,862,577 susceptibility results from isolates with age, sex, and spatial information from 944,520 individuals were used to characterise resistance prevalence patterns for 38 different bacterial species and antibiotic combinations, and 47% of these susceptibility results were from females, with a similar age distribution in both sexes (mean of 66 years old). A total of 349,448 isolates from 2019 with age and sex metadata were used to calculate incidence. We fit Bayesian multilevel regression models by country, laboratory code, sex, age, and year of sample to quantify resistant prevalence and provide estimates of country-, bacteria-, and drug-family effect variation. We explore our results in greater depths for 2 of the most clinically important bacteria-antibiotic combinations (aminopenicillin resistance in Escherichia coli and methicillin resistance in Staphylococcus aureus) and present a simplifying indicative index of the difference in predicted resistance between old (aged 100) and young (aged 1). At the European level, we find distinct patterns in resistance prevalence by age. Trends often vary more within an antibiotic family, such as fluroquinolones, than within a bacterial species, such as Pseudomonas aeruginosa. Clear resistance increases by age for methicillin-resistant Staphylococcus aureus (MRSA) contrast with a peak in resistance to several antibiotics at approximately 30 years of age for P. aeruginosa. For most bacterial species, there was a u-shaped pattern of infection incidence with age, which was higher in males. An important exception was E. coli, for which there was an elevated incidence in females between the ages of 15 and 40. At the country-level, subnational differences account for a large amount of resistance variation (approximately 38%), and there are a range of functional forms for the associations between age and resistance prevalence. For MRSA, age trends were mostly positive, with 72% (n = 21) of countries seeing an increased resistance between males aged 1 and 100 years and a greater change in resistance in males. This compares to age trends for aminopenicillin resistance in E. coli which were mostly negative (males: 93% (n = 27) of countries see decreased resistance between those aged 1 and 100 years) with a smaller change in resistance in females. A change in resistance prevalence between those aged 1 and 100 years ranged up to 0.51 (median, 95% quantile of model simulated prevalence using posterior parameter ranges 0.48, 0.55 in males) for MRSA in one country but varied between 0.16 (95% quantile 0.12, 0.21 in females) to -0.27 (95% quantile -0.4, -0.15 in males) across individual countries for aminopenicillin resistance in E. coli. Limitations include potential bias due to the nature of routine surveillance and dependency of results on model structure. CONCLUSIONS: In this study, we found that the prevalence of resistance in BSIs in Europe varies substantially by bacteria and antibiotic over the age and sex of the patient shedding new light on gaps in our understanding of AMR epidemiology. Future work is needed to determine the drivers of these associations in order to more effectively target transmission and antibiotic stewardship interventions.
\n \n\n \n \nBackgroundPlasmodium vivax remains a major challenge for malaria control and elimination due to its ability to cause relapsing illness. To prevent relapses the Indian National Center for Vector Borne Diseases Control (NCVBDC) recommends treatment with primaquine at a dose of 0.25 mg/kg/day provided over 14 days. Shorter treatment courses may improve adherence and treatment effectiveness.MethodsThis is a hospital-based, randomised, controlled, open-label trial in two centres in India. Patients above the age of 16 years, with uncomplicated vivax malaria, G6PD activity of \u2265 30% of the adjusted male median (AMM) and haemoglobin levels \u2265 8 g/dL will be recruited into the study and randomised in a 1:1 ratio to receive standard schizonticidal treatment plus 7-day primaquine at 0.50 mg/kg/day or standard care with schizonticidal treatment plus 14-day primaquine at 0.25 mg/kg/day. Patients will be followed up for 6 months. The primary endpoint is the incidence risk of any P. vivax parasitaemia at 6 months. Safety outcomes include the incidence risk of severe anaemia (haemoglobin < 8 g/dL), the risk of blood transfusion, a > 25% fall in haemoglobin and an acute drop in haemoglobin of > 5 g/dL during primaquine treatment.DiscussionThis study will evaluate the efficacy and safety of a 7-day primaquine regimen compared to the standard 14-day regimen in India. Results from this trial are likely to directly inform national treatment guidelines.Trial registrationTrial is registered on CTRI portal, Registration No: CTRI/2022/12/048283.
\n \n\n \n \nHealth policy processes should be evidence-informed, transparent and timely, but these processes are often unclear to stakeholders outside the immediate policymaking environment. We spoke to 36 international malaria stakeholders to gain insights on the processes involved in the World Health Organization\u2019s Global Malaria Programme\u2019s recommendations for their treatment guidelines of P. vivax malaria. Four key themes which drew on the 3i policy framework and Shiffman\u2019s four factors that influence global and national policymaking were identified to understand these processes. Triggers for policy change and change prioritisation, evidence types that inform policy, effects of funding on decision-making processes, and transparency and communication of these processes to external stakeholders. Results indicate that more clarity is needed on what triggers global malaria policy change processes, a clearer justification of evidence types used to inform policymaking, better understanding of the impact of the WHO\u2019s funding model on policymaking and further transparency and improved communication of these processes to external stakeholders is also needed. We suggest that global malaria policymaking could be improved by using the following strategies: ensuring that identified triggers actually initiate the policy change process, expediting decision-making timelines by developing a priority framework for assessing new evidence, adopting suitable frameworks to assess contextual evidence, and increasing the transparency of the role of non-state funders in policy decision-making processes and when publishing new recommendations.
\n \n\n \n \n\nObjectives:\nTo develop a clinical prediction model to risk stratify children admitted to PICUs in locations with limited resources, and compare performance of the model to nine existing pediatric severity scores.\n\n\nDesign:\nRetrospective, single-center, cohort study.\n\n\nSetting:\nPICU of a pediatric hospital in Siem Reap, northern Cambodia.\n\n\nPatients:\nChildren between 28 days and 16 years old admitted nonelectively to the PICU.\n\n\nInterventions:\nNone.\n\n\nMeasurements and Main Results:\nClinical and laboratory data recorded at the time of PICU admission were collected. The primary outcome was death during PICU admission. One thousand five hundred fifty consecutive nonelective PICU admissions were included, of which 97 died (6.3%). Most existing severity scores achieved comparable discrimination (area under the receiver operating characteristic curves [AUCs], 0.71\u20130.76) but only three scores demonstrated moderate diagnostic utility for triaging admissions into high- and low-risk groups (positive likelihood ratios [PLRs], 2.65\u20132.97 and negative likelihood ratios [NLRs], 0.40\u20130.46). The newly derived model outperformed all existing severity scores (AUC, 0.84; 95% CI, 0.80\u20130.88; p < 0.001). Using one particular threshold, the model classified 13.0% of admissions as high risk, among which probability of mortality was almost ten-fold greater than admissions triaged as low-risk (PLR, 5.75; 95% CI, 4.57\u20137.23 and NLR, 0.47; 95% CI, 0.37\u20130.59). Decision curve analyses indicated that the model would be superior to all existing severity scores and could provide utility across the range of clinically plausible decision thresholds.\n\n\nConclusions:\nExisting pediatric severity scores have limited potential as risk stratification tools in resource-constrained PICUs. If validated, our prediction model would be a readily implementable mechanism to support triage of critically ill children at admission to PICU and could provide value across a variety of contexts where resource prioritization is important.\n
\n \n\n \n \nUsing nasopharyngeal (NP) swab samples instead of lower respiratory tract specimens for polymerase chain reaction (PCR) to diagnose Pneumocystis jirovecii pneumonia (PJP) may be better tolerated and improve diagnostic accessibility. In this 2-year Australian retrospective cohort study of patients with clinically suspected PJP, P jirovecii PCR on NP swab samples had perfect specificity but low sensitivity (0.66).
\n \n\n \n \n\n Vaccination with the recombinant viral vectors chimpanzee adenovirus 63 followed by modified vaccinia Ankara both encoding the malaria sequence ME-TRAP conferred 67% protection against infection with\n Plasmodium falciparum\n in Kenyan adults.\n
\n \n\n \n \nIntroduction: Vaccines and drugs for the treatment and prevention of COVID-19 require robust evidence generated from clinical trials before they can be used. Decisions on how to apply non-pharmaceutical interventions such as quarantine, self-isolation, social distancing and travel restrictions should also be based on evidence. There are some experiential and mathematical modelling data for these interventions, but there is a lack of data on the social, ethical and behavioural aspects of these interventions in the literature. Therefore, our study aims to produce evidence to inform (non-pharmaceutical) interventions such as communications, quarantine, self-isolation, social distancing, travel restrictions and other public health measures for the COVID-19 pandemic. Methods: The study will be conducted in the United Kingdom, Italy, Malaysia, Slovenia and Thailand. We propose to conduct 600-1000 quantitative surveys and 25-35 qualitative interviews per country. Data collection will follow the following four themes: (1) Quarantine and self-isolation (2) social distancing and travel restrictions (3) wellbeing and mental health (4) information, misinformation and rumours. In light of limitations of travel and holding in-person meetings, we will primarily use online/remote methods for collecting data. Study participants will be adults who have provided informed consent from different demographic, socio-economic and risk groups. Discussion: At the time of the inception of the study, United Kingdom, Italy, Malaysia, Slovenia and Thailand have initiated strict public health measures and varying degrees of \"lockdowns\" to curb the pandemic. These public health measures will change in the coming weeks and months depending on the number of cases of COVID-19 in the respective countries. The data generated from our study could inform these strategies in real time.
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