Evaluation and Clinical Correlation of 18SrRNA and Microscopy in the Detection of Plasmodium falciparum among Children in Ilorin, Nigeria

Abstract

Accurate and timely diagnosis remains essential for effective malaria control, especially among children in endemic regions. While light microscopy remains the standard diagnostic tool in many healthcare settings, molecular techniques such as 18SrRNA polymerase chain reaction (PCR) offer improved sensitivity, particularly for detecting low-density or sub-microscopic infections. This study compared the diagnostic performance of 18SrRNA PCR and light microscopy in detecting Plasmodium falciparum among children aged 1–12 years in Ilorin, Nigeria, during antimalarial drug efficacy assessment. A cross-sectional diagnostic evaluation was conducted among 51 children presenting with clinical symptoms of malaria and high parasitemia density of ≥2000μᶩ. Blood samples were collected and tested for P. falciparum on Days 0, 1, 2, and 3 using both microscopy and 18SrRNA PCR. Infection trends were analyzed over time, and the results were descriptively compared. Socio-demographic and environmental factors were also examined to assess potential associations with infection status. At baseline (Day 0), 100% of the children were positive by microscopy, while 96.1% tested positive by 18SrRNA PCR. PCR detected additional infections on Days 1 and 2 that microscopy missed, highlighting its greater sensitivity during parasite clearance. By Day 3, both methods detected infections in only 3.9% of the children. Although no statistically significant associations were observed between infection and factors such as age, water source, or toilet type, children exposed to open water and unimproved sanitation consistently had higher infection rates. Both microscopy and 18SrRNA PCR remains valuable for malaria diagnosis in endemic regions. However, the enhanced sensitivity of 18SrRNA PCR during post-treatment monitoring underscores its value in detecting low-density infections and assessing treatment efficacy. Integrating molecular diagnostics into research and targeted surveillance may improve case detection and malaria control outcomes, especially in high-risk pediatric populations.