PCR-Based Detection of Mixed Plasmodium Infections in Asymptomatic Carriers
Prosper Chidi Nwachukwu *
Department of Biological Science, Clifford University, Owerrinta, Abia State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Asymptomatic and mixed Plasmodium infections represent significant but often overlooked challenges to malaria control and elimination, particularly in endemic regions. Conventional diagnostic methods such as microscopy and rapid diagnostic tests (RDTs) have limited sensitivity for detecting low-density parasitemia and mixed-species infections, potentially leading to underestimation of true infection burden. This study aimed to evaluate the effectiveness of polymerase chain reaction (PCR) in detecting asymptomatic and mixed Plasmodium infections and to compare its performance with microscopy and RDTs.
Methods: A cross-sectional study was conducted among individuals in a malaria-endemic setting. Blood samples were collected and analyzed using microscopy, RDTs, and PCR. Diagnostic performance, including sensitivity and specificity, was assessed, and the prevalence of asymptomatic, submicroscopic, and mixed infections was determined.
Results: PCR detected a higher prevalence of malaria infections (28.5%) compared to microscopy (17.3%) and RDTs (19.1%). A substantial proportion of infections (39.2%) were submicroscopic and undetectable by conventional methods. Mixed Plasmodium infections accounted for 9.8% of PCR-positive cases but were largely missed by microscopy and RDTs. While microscopy and RDTs demonstrated high specificity, their sensitivity was significantly lower than that of PCR.
Conclusion: PCR provides superior sensitivity for detecting asymptomatic and mixed Plasmodium infections and reveals a considerable hidden reservoir of malaria transmission. Integrating molecular diagnostic tools into surveillance systems is essential for improving case detection, guiding treatment strategies, and supporting malaria elimination efforts.
Keywords: Malaria, asymptomatic infection, mixed plasmodium infection, PCR, Microscopy, rapid diagnostic test, submicroscopic parasitemia, malaria elimination.