The epidemiology and detectability of asymptomatic Plasmodium vivax and Plasmodium falciparum infections in low, moderate and high transmission settings in Ethiopia

Abstract Background As countries move to malaria elimination, detecting and targeting asymptomatic infections might be needed. Here, the epidemiology detectability of Plasmodium falciparum vivax were investigated in different transmission settings Ethiopia. Method: A total 1093 dried blood spot (DBS) samples collected from afebrile apparently healthy individuals across ten study sites Ethiopia 2016 2020. Of these, 862 community 231 school based cross-sectional surveys. Malaria infection status was determined by microscopy or rapid diagnostics tests (RDT) 18S rRNA-based nested PCR (nPCR). The annual parasite index (API) used classify endemicity as low (API > 0 < 5), moderate ? 5 100) high assessed these settings. Results In surveys, overall prevalence microscopy/RDT, nPCR all methods combined 12.2% (105/860), 21.6% (183/846) 24.1% (208/862), respectively. proportion positive that detectable microscopy/RDT 48.7% (73/150) for P. 4.6% (2/44) . Compared settings, likelihood increased (Adjusted odds ratio [AOR]: 3.4; 95% confidence interval [95% CI] 1.6–7.2, P = 0.002) endemic (AOR 5.1; CI 2.6–9.9, 0.001). After adjustment site correlation between observations same survey, per year increase 0.95, 0.9–1.0, 0.013) declined with age. Conclusions Conventional missed nearly half reservoir detected nPCR. particularly older age groups These findings highlight need sensitive diagnostic tools detect entire potential transmitters.