Under the Radar: Epidemiology of Plasmodium ovale in the Democratic Republic of the Congo

Abstract Background Plasmodium ovale is an understudied malaria species prevalent throughout much of sub-Saharan Africa. Little is known about the distribution of ovale malaria and risk factors for infection in areas of high malaria endemicity. Methods Using the 2013 Democratic Republic of the Congo (DRC) Demographic and Health Survey, we conducted a risk factor analysis for P. ovale infections. We evaluated geographic clustering of infections and speciated to P. ovale curtisi and P. ovale wallikeri through deep sequencing. Results Of 18 149 adults tested, we detected 143 prevalent P. ovale infections (prevalence estimate 0.8%; 95% confidence interval [CI], .59%–.98%). Prevalence ratios (PR) for significant risk factors were: male sex PR = 2.12 (95% CI, 1.38–3.26), coprevalent P. falciparum PR = 3.52 (95% CI, 2.06–5.99), and rural residence PR = 2.19 (95% CI, 1.31–3.66). P. ovale was broadly distributed throughout the DRC; an elevated cluster of infections was detected in the south-central region. Speciation revealed P. ovale curtisi and P. ovale wallikeri circulating throughout the country. Conclusions P. ovale persists broadly in the DRC, a high malaria burden country. For successful elimination of all malaria species, P. ovale needs to be on the radar of malaria control programs. Plasmodium ovale is present and broadly distributed throughout the Democratic Republic of Congo (DCR) at an estimated prevalence of 0.8%. Both species, P. ovale wallikeri and P. ovale curtisi, were identified as occurring throughout the DRC.