The Epidemiology of Plasmodium vivax Among Adults in the Democratic Republic of the Congo: A Nationally-Representative, Cross-Sectional Survey

ABSTRACT Background Reports of P. vivax infections among Duffy-negative hosts have begun to accumulate throughout sub-Saharan Africa. Despite this growing body of evidence, no nationally representative epidemiological surveys of P. vivax in sub-Saharan Africa nor population genetic analyses to determine the source of these infections have been performed. Methods To overcome this critical gap in knowledge, we screened nearly 18,000 adults in the Democratic Republic of the Congo (DRC) for P. vivax using samples from the 2013-2014 Demographic Health Survey. Infections were identified by quantitative PCR and confirmed with nested-PCR. P. vivax mitochondrial genomes were constructed after short-read sequencing. Risk factors, spatial distributions and population genetic analyses were explored. Findings Overall, we found a 2.96% (95% CI: 2.28%, 3.65%) prevalence of P. vivax infections across the DRC. Nearly all infections were among Duffy-negative adults (486/489). Infections were not associated with typical malaria risk-factors and demonstrated small-scale heterogeneity in prevalence across space. Mitochondrial genomes suggested that DRC P. vivax is an older clade that shares its most recent common ancestor with South American isolates. Interpretation P. vivax is more prevalent across the DRC than previously believed despite widespread Duffy-negativity. Comparison to global and historical P. vivax sequences suggests that historic DRC P. vivax may have been transported to the New World on the wave of European expansion. Our findings suggest congolese P. vivax is an innocuous threat given its relatively flat distribution across space, lack of malaria risk factors, and potentially ancestral lineage. Funding National Institutes of Health and the Wellcome Trust.