Non-falciparum species and submicroscopic infections in three epidemiological malaria facets in Cameroon

Abstract

Background: There are growing reports on the prevalence of non-falciparum species and submicroscopic infections in sub-Saharan African countries but little information is available from Cameroon. Methods: A hospital-based cross-sectional study was carried out in four towns (Douala, Maroua, Mayo-Oulo, and Pette) from three malaria epidemiological strata (Forest, Sahelian, and Soudanian) of Cameroon. Malaria parasites were detected by Giemsa light microscopy and polymerase chain reaction (PCR) assay. Non-falciparum isolates were characterized and their 18S gene sequences were BLASTed for confirmatory diagnosis. Results: PCR assay detected malaria parasites in 82.4% (98/119) patients, among them 12.2% (12/98) were asymptomatic cases. Three Plasmodium species viz. P.falciparum, P.ovalecurtisi and P.vivax, and two co-infection types (P.falciparum + P.vivax and P.falciparum + P.ovalecurtisi) were found. The remaining infections were mono–infections with either P.falciparum or P.ovalecurtisi. All non–falciparum infections were symptomatic and microscopic. The overall proportion of submicroscopic infections was 11.8% (14/119). Most asymptomatic and submicroscopic infection cases were self-medicated with antimalarial drugs and/or medicinal plants. On analysis, P.ovalecurtisi sequences were found to be phylogenetically closer to sequences from India while P.vivax isolates appeared closer to those from Nigeria, India, and Cameroon. No G6PD-d case was found among non-falciparum infections. Conclusions: This study confirms our previous work on circulation of P.vivax and P.ovalecurtisi and the absence of P.knowlesi in Cameroon. More studies are needed to address non-falciparum malaria along with submicroscopic infections for effective malaria management and control in Cameroon.