Quantitative PCR-Based Diagnosis of Soil-Transmitted Helminth Infections: Faecal or Fickle?

Treatment and control programmes tackling soil-transmitted helminth (STH) infections require sensitive, reliable, and accurate diagnostic tools. There is a growing need for measures of infection intensity as programmes approach STH control. Quantitative real-time PCR (qPCR) is well suited to the detection of DNA targets present in stool, even in low-prevalence settings. Detecting low levels of infection becomes increasingly important when the breakpoint of transmission is approached, and is vital when monitoring for recrudescence once control, or possibly 'elimination', is achieved. We address key challenges and questions that remain as barriers to incorporating qPCR as a cornerstone diagnostic tool for STH infections. Programmes for treating or controlling infections or diseases caused by soil-transmitted helminths (STHs) require the use of sensitive, specific, and practical diagnostic tools to monitor their success.Conventional coprological methods are often used for the microscopic detection of worm eggs, but there is a need for improved sensitivity and measures of infection intensity as programmes approach STH elimination.‘Transmission breakpoint’ has promoted the adoption of qPCR as a diagnostic tool.There can be challenges in relying on qPCR as a 'gold-standard' diagnostic tool for STH infections; a point in question would be copy number variation of the molecular target in the parasites.Studies are required to accurately relate qPCR data (in relation to target copy number) to infection intensity.