Prevalence of Plasmodium malariae in South Eastern Nigeria

Objectives Routine detection of  Plasmodium malariae, which is one of five species that infect humans is not done because the common diagnostic tools do not distinguish between plasmodium species. Submicroscopic infections of any parasite species pose a significant challenge to malaria elimination. The objective of this study is to determine the prevalence and population at risk of P. malariae  infection in a high transmission setting. Methods Participants were recruited from four Health Facilities in southeastern Nigeria from October to November 2018. Pan-species rapid diagnostic test (RDT) was used for diagnosis and results were compared with PCR detection.  Results Out of 799 participants recruited, ratio of male to female was 44%:56%. Age group distribution was 12%, 16%, 21% and 51% respectively for 0-5, 6-10, 11-15 and >15yrs. Plasmodium prevalence by RDT across the four Health facilities was 23.4%, with P. falciparum detected in 84.4%-100%; pan-species mixed with P. falciparum  in 2.2%-40.6%; and pan-species positive only in 0%-15.6% .  P. malariae  was detected in 10.3% of the participants by PCR, 76.8% of which occurred in individuals >11yrs. Conclusions The age group with the most  P. malariae  infections are not often targeted for interventions, therefore routine diagnosis of non-falciparum species is important for proper administration of interventions.