Molecular Documentation of Plasmodium Species Diversity in Asymptomatic Malaria Carriers in Enugu Urban Communities

Asymptomatic malaria infections serve as an important parasite reservoir for ongoing transmission in endemic communities, yet they are frequently undetected by rapid diagnostic tests and clinical screening. Comprehensive molecular documentation of Plasmodium species contributing to asymptomatic carriage in Nigerian urban settings provides data critical for transmission interruption strategies. This study documented Plasmodium species diversity in asymptomatic individuals in three urban communities in Enugu State, Southeast Nigeria. Community-based cross-sectional surveys were conducted in Enugu, Abakpa, and Ugwuaji. Blood samples were collected from 300 asymptomatic individuals, and species-level parasite detection was performed by nested PCR targeting the small subunit ribosomal RNA (ssrRNA) genes of P. falciparum, P. malariae, P. ovale curtisi, and P. vivax. P. falciparum was detected in 27.3% of asymptomatic samples, while P. malariae accounted for 9.7%. Mixed infections of P. falciparum and P. malariae were detected in 6.7% of PCR-positive samples. P. ovale was detected in 2.3%, and P. vivax was absent. Asymptomatic carriage was significantly higher in children aged 5-14 years. These molecular findings demonstrate the predominance of asymptomatic mixed Plasmodium infections in urban Enugu and underscore the need for community-targeted active case detection in malaria elimination strategies. Keywords: asymptomatic malaria, Plasmodium species, nested PCR, urban malaria, Enugu State.