Revealing the hidden burden: multiplex real-time PCR for ‘endgame’ surveillance of soil-transmitted helminthiasis in Fiji
Milika Rinamalo, Sung Hye Kim, Mike Kama, Jaco J Verweij, Hanna Jin, Sung-Tae Hong, Min-Ho Choi, J Russell StothardAbstract
Objectives
Soil-transmitted helminthiasis (STH) remains a global health concern. As control programmes approach transmission interruption, sensitive diagnostics are needed to detect residual infections. This study compared conventional microscopy with real-time PCR for STH surveillance among primary schoolchildren in Fiji.
Methods
A total of 1,081 grade 1–2 children were screened by Kato-Katz (KK) thick smear and the formalin-ether concentration technique. A subset of samples was analysed by multiplex real-time PCR targeting Ascaris sp., Necator americanus, Ancylostoma sp., Trichuris trichiura, and Strongyloides sp..
Results
In subgroup A (n = 90, a systematic 10% sample), real-time PCR detected any STH in 21.1% of children (19/90; 95% CI: 14.0–30.6) compared with 5.6% by microscopy (5/90; 95% CI: 2.4–12.4). Across all samples tested by real-time PCR (n = 133), hookworm was dominated by Necator americanus, exceeding Ancylostoma by ∼3:1. Ascaris cycle threshold values were strongly inversely correlated with KK egg counts (Spearman’s ρ = −0.86, P < .001), confirming the semi-quantitative utility of real-time PCR.
Conclusion
Multiplex real-time PCR reveals a greater STH burden than microscopy in this low-endemicity setting, providing species-level resolution and semi-quantitative capacity suitable for endgame surveillance. Quality-assured molecular diagnostics should be integrated into STH monitoring frameworks.