PHARE - Pilot for Harnessing self-limiting male Anopheles stephensi for malaria control: Research and Evaluation

Over the past two decades Djibouti has undergone a dramatic shift in malaria epidemiology. In the mid-2000s transmission was reliably low, and the national control programme launched in 2006 aimed to eliminate malaria by 2020 through rapid diagnosis, treatment and vector control. Around 2010 cases began to rise sharply, coinciding with the first detection of Anopheles stephensi, an invasive mosquito native from South Asia. Unlike African vectors, An. stephensi thrives in dense urban settings and breeds in household water containers, construction sites and other human made habitats typical of rapidly urbanising cities. It became Djibouti's primary malaria vector during the mid 2010s.

In 2022 Djibouti's Ministry of Health partnered with Flyttr (formerly Oxitec) to test self-limiting genetically modified An. stephensi males, with funding from the Gates Foundation. Released males carry a gene that prevents female offspring from surviving, so mating with wild females gradually suppresses the local mosquito population, because female carriers do not survive, the gene fades from the population without continued releases. Following laboratory and small scale field studies in Djibouti demonstrating that released males survive, disperse and mate successfully with wild females, this project will evaluate the entomological, epidemiological and operational impact of expanding releases to 50 hectare and then 350 ha areas in urban Djibouti in two transmission seasons. The evidence generated will inform potential national scale up, guide whether the approach can be applied in other cities threatened by An. stephensi, and help refine methods for evaluating novel vector control interventions under real-world urban conditions.