Molecular diagnostics reveal substantial sub-patent schistosomiasis and soil-transmitted helminth infections in school children: An implication for elimination programme

BACKGROUND: Schistosomiasis and soil-transmitted helminthiasis elimination programmes rely on microscopic diagnostics, yet molecular methods may detect sub-patent infections invisible to conventional screening. OBJECTIVE: To quantify sub-patent parasitic infections undetected by microscopy and estimate true prevalence using latent class analysis among primary school children across six Nigerian states. METHODS: We conducted a multi-state cross-sectional study among 7,560 systematically sampled primary school children from Plateau, Rivers, Ebonyi, Kano, Benue, and Ondo States. All participants provided urine and stool specimens analysed using standard microscopy. A stratified random subset of 3,236 samples (42.8%) underwent molecular confirmation using multiplex PCR and quantitative real-time PCR. Bayesian latent class analysis estimated true prevalence accounting for imperfect sensitivity of both diagnostic methods. RESULTS: Microscopy revealed overall parasitic infection prevalence of 20.7% (1,565/7,560; 95% CI: 19.8-21.7%). Among the molecular subset (n=3,236), PCR detected 983 positive cases versus 680 by microscopy (44.6% increase; 95% CI: 40.8-48.5%; p