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A clamor invaded the port of Bubaque. At the end of the afternoon, a long canoe loaded with medicines has just landed on this island of Guinea-Bissau located in the Bijagos archipelago. A team of researchers dispatched by the London School of Hygiene and Tropical Medicine (LSHTM) is rushing to unload tens of thousands of drugs straight from The Gambia, where the London University has a research unit, and store them in a storage center.
“Tomorrow, we will send supervisors to the various inhabited islands and then, in a few days, the drugs will be distributed to the population”, details Harry Hutchins, researcher at LSHTM.
The scene takes place in July, at the time of the launch of the Matamal project, funded to the tune of 3.6 million euros by several British research and development organizations. The objective: to assess the impact of adding a molecule, ivermectin, to the basic drug composed of dihydroartemisinin-piperaquine in the fight against malaria. And thus reduce the prevalence of this disease which today affects 28% of some 30,000 inhabitants of the archipelago, in particular children and pregnant women.
Some Bijagos mosquitoes are said to be particularly resistant to insecticides. The most common means of infection control such as mosquito nets and insecticides are therefore ineffective. “This means that another strategy is necessary”says Professor James Logan, head of the disease control department at LSHTM.
The treatment or the placebo
Ivermectin, a preventative that requires nine doses three days a month during the rainy season, is believed to kill mosquitoes as they suck blood. It targets both the insect and the malaria parasite, shortening their lifespan.
“We are not going to eradicate the disease with this kind of drug, tempers Claire Collin, public health research assistant at the London School. But we hope at least to reduce contamination, the prevalence and therefore deaths during the rainy season. “
This mission should last more than two years. Some 25,000 inhabitants are concerned by the research, ie almost the entire population of the archipelago. From July and for four months, the drugs were distributed blindly to the inhabitants: in some villages, the real treatment, in others a placebo.
The communities generally played the game. Depending on the village, between 50% and more than 90% of the population took all the medicines each month. A second distribution is scheduled for 2022.
An adapted geography
The Bijagos Islands were not chosen by chance to conduct this study. The archipelago has the unfortunate feature of harboring many serious diseases and ailments: malaria, but also trachoma (a serious eye infection), elephantiasis or even intestinal worms.
If the life expectancy in Guinea-Bissau is around 60 years, “We think it is much shorter on the Bijagos, underlines Professor James Logan. But these islands may hold also the secret to fighting the diseases that ravage them. “
For researchers, the place is an open-air laboratory. Isolated, its inhabitants have very little interaction with other communities. “When you do a clinical trial like this, you have to avoid contamination between populations. However, here, it is very simple, there is no external contaminations generated by other populations of mosquitoes ”, specifies Claire Collin. While on the mainland, people can easily enter and leave test areas and become contaminated elsewhere, making it difficult to establish causes and effects.
While there are many archipelagos around the world, few are geographically as suitable as the Bijagos, with islands close enough to work in place, but far enough apart to minimize interference during experiments. Mosquitoes, vectors of the infection, do not live more than three weeks and never exceed a radius of 2 kilometers, the distance of the different buffer zones.
On the small islands, the “ivermectin” and “placebo” villages are naturally separated by water, while on the larger islands, the areas have been fixed by the researchers. “In terms of scientific theory, there is no better, it is the best laboratory to know if our drug theory works”, develops Claire Collin.
Proof that this kind of experiment can give results, the researchers at LSHTM were first interested in the trachoma present on the islands, an infectious disease which causes the eyelashes to tilt inward. Affecting nearly 2 million people in around 40 countries around the world, it is considered the leading cause of preventable blindness worldwide.
Anna Last, infectious disease doctor at LSHTM, identified areas at high risk for trachoma in the Bijagos, before treating entire communities by carrying out massive distributions of antibiotics to end the cycle of transmission.
“The results were striking, underlines James Logan. When she started working on the subject in 2010, 25% of the inhabitants of Bijagos had the disease. Ten years later, only 0.3% of people are. “
This level is below the elimination threshold set by the World Health Organization (WHO), which means that the disease is virtually eradicated from the islands. For the malaria control project, the results are expected in 2023. This life-size test is intended to benefit other tropical countries affected by malaria, which kills an average of 400,000 people each year, the overwhelming majority of them in Africa.
Guinea-Bissau: the Bijagos archipelago, a fragile paradise
It takes more than three hours to sail aboard a motorized canoe from Bissau, the capital of Guinea-Bissau, to reach the 88 islands and islets that make up the Bijagos archipelago. The remoteness has long allowed ancestral traditions to continue in this paradise of sea hippos and turtles where some 30,000 people live.
But the archipelago is gradually opening up to the world: island tourism is developing, new religions are taking hold and attracting more educated and connected Bijago youth. The dominance of women and animist beliefs are declining and the gap is widening between the generations.
More accessible, the archipelago is also of interest to researchers who are carrying out scientific trials to fight against the many diseases affecting populations. The World Africa offers you a three-part series to tell about some of the changes underway on this unique but fragile archipelago.
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Guinea-Bissau: the Bijagos, an open-air laboratory