Evaluating the determinants of the spread of COVID-19 between and within rural communities in Mali, West Africa based on blood-fed mosquitoes

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The spread of COVID-19 in rural sub-Saharan Africa is poorly understood and reliable data are unlikely to be obtained. To fill this gap and assess how the unique ecological and cultural settings affect it, we have initiated a novel strategy of non-invasive, high throughput monitoring of COVID-19 infections by sampling blood-fed mosquitoes collected monthly in 20 Malian villages spread across 500km. The mosquito blood meal will be used to detect antibodies against COVID19 by ELISA. Presently, recruitment of all 20 villages has been completed including 3 villages where collaborators will carry out serological tests on residents as part of their own projects and will share anonymous data with us for comparison and validation. Testing of several exit trap designs and SOP optimization are ongoing in several villages. Training of local teams in mosquito collection and preservation is ongoing, while pilot collection of mosquito specimens has been implemented. We expect that all villages will be trained and operational by September 2020. Laboratory experiments to identify infection status based on mosquito blood meals are planned and will start as soon as the key reagents (e.g., positive control sera from individuals who have been exposed to COVID19 and who have an average titer of IgG) will arrive to our laboratory. Our goal is to determine the window of time after blood meal that detection of antibodies is reliable, given expected titer for two widely used epitopes.