Estimating the potential impact of surveillance test-and-treat posts to reduce malaria in border regions in sub-Saharan Africa: a modelling study

The last malaria cases in near-elimination settings are often found in international border regions due to the presence of hard-to-reach populations, conflict, uneven intervention coverage, and human migration. Test-and-treat border posts are an under-researched form of active case detection used to interrupt transmission chains between countries. We used an individual-based, mathematical metapopulation model ofP. falciparumto estimate the effectiveness of border posts on total cases in malaria-endemic sub-Saharan Africa. We estimated that implementation of international border posts across 401 sub-national administrative units would avert a median of 7,173 (IQR: 1,075 to 23,550) cases per unit over a 10-year period and reducePfPR_2-10by a median of 0.21% (IQR: 0.04% to 0.44%). Border posts were most effective in low-transmission settings with high-transmission neighbors. Border posts alone will not allow a country to reach elimination, particularly when considering feasibility and acceptability, but could contribute to broader control packages to targeted populations.