Gates award (1 million USD) for Teun Bousema

Bousema Teun
Eliminating malaria by a targeted interventions

Every year an estimated 750.000 African children die of malaria. However, not all children experience the same risk of this deadly disease. There is considerable variation in the exposure to malaria, not only between different African countries or regions in these countries. Also between neighbouring villages and even within villages, differences in malaria risk can be considerable.

Hotspots

Teun Bousema, epidemiologist of the Radboud University Nijmegen, the Netherlands, proposed to make use of this variation in malaria exposure to eliminate malaria.If certain households are most affected by malaria, he reasoned, they are probably also very important for malaria transmission. Humans are infected by bites of infected Anopheles mosquitoes. In turn, humans also form the source of malaria infection for uninfected mosquitoes. In this manner, a hotspot of transmission can form where human super-spreaders transmit their infection to large numbers of mosquitoes?

Immune profile

Bousema received Grand Challenge Exploration funding for his innovative idea from the Bill & Melinda Gates Foundation in 2008. With these funds, he successfully collected evidence for his hypothesis in four villages in Mali and Tanzania. Approximately eighty percent of all clinical disease episodes occurred in twenty percent of the children. The households of these children were also disproportionally exposed to malaria-transmitting mosquitoes and mosquitoes most frequently acquired their infection in these households. Although these findings supported the hypothesis, they did not immediately enable targeted interventions. How does one identify hotspots? Households that were closest to mosquito breeding sites frequently did not form hotspots and very intense hotspots sometimes appeared in unpredictable places. Bousema: We have solved this issue by studying the immune response of humans after exposure to malaria. After malaria exposure, antibodies are acquired against parts of the malaria parasite. People who are most intensely exposed to malaria acquire antibodies faster and against a larger number of parasite proteins. In the Gates-funded study, hotspots were sensitively predicted by determining geographical patterns in the speed at which humans acquire anti-malaria antibodies. These immune profiles also allowed a rapid identification of hotspots in areas where no prior malaria research had been conducted.

Eliminate malaria locally

On the basis of these results, the Bill & Melinda Gates Foundation has decided to award Bousema a Grand Challenge grant of 1 million USD. With this money, large-scale research will be conducted in Kenya and Mali to determine whether targeted interventions can indeed lead to local elimination of malaria. If this works, this approach forms a new weapon in the worldwide battle against malaria.


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