A reliable ex vivo invasion assay of human reticulocytes by Plasmodium vivax
Plasmodium vivax is the most important cause of malaria in Asia and South America, infecting more than 200 million people each year. There is no vaccine, and the vivax parasite is now resistant to many of the first line antimalarial drug treatments, such as chloroquine. Accentuating these problems is the fact that the vivax parasite is notoriously difficult to study, hampering efforts to develop effect control measures.
To remedy this situation clinicians from SMRU teamed up with the Singapore Immunology Network (part of the Agency for Science, Technology and Research (A*STAR)) to develop a powerful assay for testing vaccine candidates against the blood stage forms of the vivax malaria parasite. This method was validated by testing a leading vaccine candidate that targets the need for the P. vivax parasite to bind to a specific protein (called a “Duffy receptor”) in the human red blood cell before it can invade it. This study revealed that the effectiveness of such vaccines are significantly affected by genetic variation in the parasite. Four more vaccine candidates are currently being tested.
Bursting to get in! Minutes after the mature blood form of the vivax malaria parasite bursts from the human red blood cell it is ready to attach and invade young blood cells (stained light blue by Geimsa in the picture above).
The picture above shows ex vivo matured and concentrated P. vivax collected from a Burmese patient at Prof. Francois Nosten’s SMRU clinic, Mae Sod, Tak. Picture Taken by Bruce Russell 2011
Giving communities a greater voice in research
Shoklo Malaria Research Unit (SMRU) is working as part of a Wellcome Trust initiative to explore the value of participatory video as a tool for community engagement.
SMRU is located in Thailand’s northwestern Tak province, with its clinics immediately adjacent to the Burmese border. Since 1986 SMRU has been providing healthcare and conducting operational research amongst the border population, composed of refugees, displaced people and migrant workers from Burma – SMRU is the only healthcare provider that many of these people can access.
Since 2008, SMRU has been working with representatives from the border population to establish and run the Tak Province Border Community Ethics Advisory Board (T-CAB) which catalyses community discussion about the work of SMRU and represents the local people’s views in the development of SMRU’s research projects and provision of health services.
As part of the new Wellcome Trust initiative, T-CAB members have been provided with video cameras and training in their use and they are now planning to: capture and share their communities’ discussions and experiences so that they can be used to inform bring authentic voices of the community to researchers.
Saw Aung Than Wai a member of T-CAB said:
The T-CAB member is the bridge, or the joiner between the community members and the researchers. The researchers present something, concerns or risks/benefits and they have to be clear the community people understand these.
Listening is important during communication because we have different backgrounds and different attitudes as well as different opinions. Sometimes if we’re not a good listener, we may interpret in a different way, and it may cause a different meaning.
This method of “participatory video” is being explored to make films that can support new T-CAB members’ confidence and understanding of research to fully participate in the group’s work; enable communities living in different areas to share their points of view with one another (this is important because SMRU operates sites which are more than 100km apart); and to give communities a direct voice in the development of studies, and potentially to convey the communities’ needs in funding applications to the international donor community.
For the people: the Laos collaboration
By Katherine Nightingale
Ten years ago, information on infectious disease in Laos was scarce. The Wellcome Trust-Mahosot Hospital Oxford University Tropical Medicine Research Collaboration has gone some way to changing that. Katherine Nightingale visits the research unit run for the people, by the people, which has made giant leaps in a country’s medical knowledge.
Dr Paul Newton wasn't expecting to get into goat husbandry when he came to Laos. But the three goats that live in the yard of the Mahosot Hospital in Vientiane earn their keep as a ready supply of blood for bacterial culture and are firmly part of the family.
That there have been no commercial suppliers of blood agar in Laos is no surprise. A small country of just six million people, Laos is one of the poorest in South-east Asia, sandwiched between the economically more vibrant Thailand and Vietnam. Its largely rural population suffers from a range of infectious diseases, from the familiar (such as malaria and dengue fever) to others largely unheard of, or forgotten about, outside the region. The common Lao diseases murine and scrub typhus - forms of the bacterial disease typhus transmitted by fleas and mites, respectively - and melioidosis, a bacterial infection contracted through contaminated soil or water, have only been described in Laos in the last decade. But now, through what has grown to become the Wellcome Trust-Mahosot Hospital Oxford University Tropical Medicine Research Collaboration (LOMWRU), these diseases are finally getting the attention they deserve.
Starting from scratch
The Trust's work in Laos began in 2000 in response to the almost complete lack of information about infectious disease in Laos, as well as the hospital's lack of facilities for diagnosing infectious disease apart from malaria.
"Ten years ago, on one of his visits to Vientiane, I handed the Director of the Trust a stack of all the literature I could find about Lao health. The pile was this thick," says Newton, now director of LOMWRU, indicating with his thumb and forefinger a pile around a centimetre tall.
The Ministry of Health was extrapolating from Thai, Vietnamese and even French studies to determine how to treat patients, even though the pathogens were likely to be different. There was no information on the best way to treat malaria, for example, or the main causes of fever, even though fever was - and remains - the most common symptom in people seeking medical attention in rural areas.
Early projects carried out by Lao doctors with Newton and the Trust's Thailand programme included a study of drug resistance in Salmonella typhi, which causes typhoid fever. They found that most Salmonella typhi in Laos could be treated with short course of antibiotics, unlike in many other nearby countries. "That really brought home the fact that Laos needed Lao information about diseases," says Newton.
Gradually research in Laos became more formalised, and by 2005 funding was coming from the core grant of the Wellcome Trust-Mahidol University-Oxford Tropical Medicine Research Programme in Thailand. The Laos collaboration is now one of the Programme's three main research hubs. In 2008 the new Infectious Diseases Centre, with a 30-bed infectious disease ward and biosafety category 3 labs, was opened. There are now 42 staff working at LOMWRU - up from five when the work first began. Most of the researchers are Lao, and some also work at the University of Health Sciences, providing an important link between the two institutions.
From just three research areas - malaria, septicaemia and infantile beriberi (thiamin deficiency) - LOMWRU now runs more than 50 research projects, and the corridors of their brand-spanking new labs are lined with some of the 115 research papers about Lao disease that the programme has published in the past decade. LOMWRU was also key in launching the country's first medical journal, the 'Lao Medical Journal', in 2010, providing a new way to distribute health information in the Lao language.
For the people
In a country where a person can easily die with fever without ever seeking medical attention, studying the diagnosis, epidemiology and treatment of the diverse causes of fever are central to the programme's work.
"It all started with the question of fever…and to a certain extent that what's we're still trying to find out. It's a real Pandora's box, we keep uncovering more questions than we're answering," says Newton.
Dr Mayfong Mayxay, head of field research at LOMWRU and head of the University of Health Sciences' new research centre, says the collaboration's work has vastly improved diagnosis and treatment.
"In the past the doctors in our hospital found it difficult to request the blood cultures for the patients with prolonged fever because most could not afford to pay and hence there were very few data on the causes of fever. But now blood cultures have become routine tests that the doctors can request easily."
But Newton and Mayxay agree that perhaps the collaboration's most significant achievement has been in malaria treatment research. LOMWRU researchers showed that the use of an antimalarial called artemether-lumefantrine was much more effective than the national policy of treating uncomplicated Plasmodium falciparum malaria with the older drugs chloroquine and sulphadoxine-pyrimethamine, prompting the government to change treatment guidelines.
Another important step has been the finding that murine and scrub typhus are an important cause of non-malarial fever in Laos. Newton says there is little evidence on the best way to treat scrub typhus and none on murine, so they are now carrying out clinical trials to find out. "The Ministry of Health is very receptive to hearing results and considering changes in health policy," he says. Finding better treatment saves lives, but also drugs and hospital resources. The latter two are crucial factors in Laos' out-of-pocket health system. But as well as helping the system, it also saves patients money, both for the treatment they receive and by reducing the time they need to spend in hospital.
The researchers are on the trail of drug counterfeiters too. LOMWRU-coordinated researchers were the first in the world to use chemical and pollen analysis of fakes of the antimalarial artesunate, common in SE Asia, to trace where they were coming from, leading to the 2008 arrest and later imprisonment of six traders of fake antimalarials.
A researcher at LOMWRU. Image credit: LOMWRU/Joss Dimock.
But challenges remain. "Clinical research is still a new thing for Lao health workers and the Lao authorities…we have a limited number of 'true’ clinical researchers in the country who are able to conduct studies and write up papers for publication in international peer-reviewed journals," says Mayxay.
On-the-job research training, as well as Masters and PhD supervision, is therefore a fundamental part of the collaboration's activities, and Mayxay is optimistic. "We will have an increasing number of Lao clinical researchers who will become independent clinical researchers in Laos in the near future," he says.
As Laos' fledgling health research expands, Newton is keen to make sure that the programme maintains its broad research base. "We don't want to be duplicating research that others are doing, but we don't want any of these 'forgotten' diseases to get left behind," he says.
Outside in the humid afternoon, Godwin the goat is installed in a contraption resembling an elaborate bike stand, placidly munching on some leaves, patiently waiting to give blood. Everyone is doing their bit.
Top image: Godwin the goat outside LOMWRU. Credit: LOMWRU/Joss Dimock/ Wellcome Trust
