The Mekong basin at the heart of the battle against malaria

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In eastern Burma, Karen State, the rainy season is in full swing. The muddy roads snake between the green hills and everywhere, mosquitoes swarm, pampered by the water reserves that accumulate in the forest, on roads, around houses. Among them are the anopheles, whose bites transmit malaria, marsh fever, carrying parasites of the genus plasmodium from one human to another.

In the village of Htee Kaw Htaw, however, the "malaria post" remains calm. Daw Cho Cho Lwin and Moe Set Phyu, the two employees of this malaria center, confirm that there have been only 63 cases of malaria since the beginning of the year. What is happening here on the Thai-Burmese border follows the trend observed regionally in the Mekong River Basin: the incidence of malaria dropped by 54% between 2012 and 2015, reaching less than 300,000 cases per year, and the number of deaths has dropped by 84% over the same period with even fewer than 30 deaths in 2018. Compared to the global situation, it is not enough: in 2017, malaria reached 219 million number of people and resulted in the deaths of 435,000 of them, mainly in sub-Saharan Africa.

Despite apparently optimistic figures, malaria is a ticking time bomb in the Mekong basin: it is here that for decades there has been resistance to each treatment successively developed to fight against this disease. These resistances are the bane of the infectious diseases: because of them, the drugs are not so effective against parasites. Thus, resistance to chloroquine, the first synthetic antimalarial, emerged in the region in the 1950s, followed by sulfadoxine-pyrimethamine in the 1970s.

"Each time, these resistances spread throughout the Mekong basin, ended up in Burma, Bangladesh, India and Africa, where, because of the high ubiquity of mosquitoes, they had catastrophic repercussions, causing millions of deaths because the available drugs were no longer effective "explains Prof. Francois Nosten, director of the Shoklo Malaria Research Unit in Mae Sot (SMRU), Thailand, a few miles from the Burmese border.

Resistance to conventional treatments

In 2002, the first signs of resistance to artemisinin appeared in Cambodia. Now this molecule is today indispensable in the fight against the disease. It is used in combination with other molecules in TCA, artemisinin-based combination therapies, the only treatment now recommended by WHO that has drastically reduced the number of deaths in the world. Worse, since 2008, the partner molecules, whose goal is to eliminate the residue of parasites that artemisinin has not destroyed, have also begun to suffer setbacks.

Thus a strain of parasite resistant to the treatment today used in first intention in a large part of Asia, combining dihydro-artemisinin and piperaquine, is, since 2011, progressively become dominant in Cambodia, in the west of Vietnam , in southern Laos and in northeastern Thailand, replacing local parasites in these areas. The risk? That these new resistances spread as in the past to Africa.

Scientists traveling in the region of the Thai-Burma border for a malaria awareness session with peasants. Alice Bomboy

If this perspective divides the specialists, the situation is nonetheless alarming and imposes an objective: to eliminate malaria from the Mekong basin by 2030. At the Thai-Burma border, the SMRU and its local partners have put in place places an extraordinary strategy. "The idea is to eliminate the parasite before resistance takes over. Because the day when the ACT will no longer be effective, we will no longer have available treatments, explains Gilles Delmas, director of the elimination program at SMRU. For this it was necessary to set up a system that ensures both a fine surveillance of the territory, but also the diagnosis and early treatment of patients. "

"Mass treatment"

If the situation is stable on the Thai side, it is not Burmese side: the region has been devastated since 1949 by a civil war opposing the rebellion of Karens to the official army, leaving the area largely underdeveloped, especially with regard to health infrastructures. The installation of 1222 "malaria posts" between May 2014 and May 2017 in four of Karen County's cantons is a feat. The Htee Kaw Htaw Center is one of them. Both of her employees had no paramedical skills. "They are always people from the community, whom people trust. They have received a short training allowing them to use the rapid diagnostic tests which allow to know on the spot and in a few moments if a person is infected or not "explains Gilles Delmas.

If the diagnosis is positive, the patient immediately receives treatment, which can stop the development of the disease – and reduce the likelihood of passing it on. "It's a real change for us, says Thtee Paw, a young woman from the village. I have had malaria at least four times, and for treatment we had to walk more than three hours to the nearest clinic. It was so difficult to make such a trip when you are so sick and so feverish that you hardly have the strength to get out of bed. We often had to wait several days before we could go. "

This is one of the challenges we face in the region. In some people, the amount of parasites is so small that it is difficult to detect and does not make them sick either

Director of the program

In Htee Kaw Htaw, as in about sixty other villages where the inhabitants were more carriers of the parasite than in surrounding villages, the entire consenting population was treated for malaria, even those with no symptoms of the disease. : an approach called "mass treatment". "This is one of the challenges we face in the region. In some people, the amount of parasites is so small that it is difficult to detect and does not make them sick either. These people are a silent "reservoir" of parasites and spread the disease. By treating the entire population, we accelerate elimination "says the director of the program.

The results obtained are astounding: between 2014 and 2017, the number of new cases of malaria due to Plasmodium falciparum, the most virulent parasite, decreased from 60 to 94% in the four cantons. In villages where mass treatment was used, the incidence of malaria was reduced by five. In April 2017, the parasite had disappeared for at least six months in 965 of the 1222 villages studied. "These are great results, confirms Dr Pascal Ringwald, head of the Medicines Effectiveness Unit and response to the WHO Global Malaria Program. This program showed that such a strategy worked and made it possible to eliminate from a target area the parasite and the resistance carried. "

Maintain surveillance

Despite these results, countries are reluctant to use this state-wide approach. In Burma, the experiment has not been extended to other regions, where the parasite still remains. As a result, these are regularly exported to areas close to elimination in Karen State. "It's often way too expensive", summarizes the WHO specialist. Experts in the Mekong basin also fear that the success of their elimination program will distract attention from the need to continue to fund malaria control in the region.

"The risk is that the decision-makers will see only the number of local cases, which is very low, and are not interested in the problem crucial for the region and more broadly for the rest of the world: that of resistance. If we want to be able to continue to control these, we have to keep a very close watch. If we do not, an epidemic may start from imported malaria cases, resistance will spread, and all the work done until then would have been useless. It would just be a disaster », says Prof. Francois Nosten. What about the WHO position? "We are taking the issue of resistance in the Mekong River basin very seriously, although we are less alarmist about their ability to spread to Africa, as has been the case in the past. What is clear is that the work of eliminating malaria in this region has begun and is moving forward, and that it is imperative to continue it ", sums up Dr. Pascal Ringwald.

In early October in Lyon, Emmanuel Macron hosted the funding conference of the Global Fund, the main sponsor of the global fight against the "three biggest killers" that are malaria, tuberculosis and AIDS. Pledges from governments reached an amount never equaled: 14 billion dollars (12.6 billion euros), including 1.4 billion euros promised by France. In the previous three-year cycle, the Mekong River Basin had a $ 243 million budget to fight malaria. What will it be this time?

This report was produced with the support of a grant from the European Journalism Center.



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https://www.lefigaro.fr/international/le-bassin-du-mekong-au-coeur-de-la-bataille-contre-le-paludisme-20191110

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