Molecular Evidence of Submicroscopic Malaria Parasitaemia among Asymptomatic Populations in Jos, Plateau State, Nigeria

Despite ongoing malaria control efforts, the disease remains a major cause of morbidity and mortality in Nigeria. As transmission declines in many endemic settings, asymptomatic and submicroscopic infections increasingly constitute a hidden reservoir that sustains malaria transmission. These infections often escape detection by routine diagnostic methods yet remain epidemiologically significant, particularly in elimination-focused programmes. This study assessed the prevalence of asymptomatic and submicroscopic malaria parasitaemia among individuals attending selected health facilities in Jos, Plateau State, Nigeria.

A cross-sectional survey was conducted among 400 apparently healthy individuals across five selected health facilities in Jos, Plateau State, Nigeria. Participants aged ≥6 months who exhibited no clinical signs or symptoms of malaria were enrolled. Malaria parasitaemia was confirmed by Giemsa-stained microscopy, submicroscopic Plasmodium infection by 18S mRNA using nested PCR. Out of 400 participants screened, 78 (19.5%) tested positive for malaria by microscopy, with prevalence varying across health facilities from 11.2% to 30.0%. Males had a significantly higher infection prevalence (26.0%) compared to females (15.7%). Molecular analysis revealed a substantially higher burden of infection: among 120 microscopy-negative samples analysed by nPCR, 74 (61.7%) were positive, indicating a high prevalence of submicroscopic malaria parasitaemia. Although submicroscopic infections did not differ significantly across demographic groups (p > 0.05), the highest prevalence was observed among pregnant women (64.5%) and children (66.7%). Plasmodium falciparum was the predominant species (55.9%), followed by P. ovale (16.5%), P. malariae (6.5%), and P. vivax (5.3%). Asymptomatic and submicroscopic malaria infections constitute a substantial hidden reservoir in Jos, Nigeria. Reliance solely on routine diagnostic methods may lead to significant underestimation of malaria prevalence. Integrating sensitive molecular diagnostics into surveillance systems is critical for effective malaria elimination in low-to-moderate-transmission settings.