Diagnostic tools for soil-transmitted helminths control and elimination programs: A pathway for diagnostic product development
The 2020 Roadmap goals endorsed by the World Health Organization (WHO) for soil-transmitted helminths (STHs) (Ascaris lumbricoides, Ancylostoma duodenale, Necator americanus, Trichuris trichiura) are focused on mass drug administration (MDA) of anthelmintics to control morbidity associated with moderate- and heavy-intensity infection . As the STH community approaches the 75% coverage target for preschool- and school-aged children, there is increasing interest in exploring post-2020 goals that transition from simply monitoring program coverage to strengthened monitoring of a program’s impact on transmission of infection and determining whether enhanced MDA can break STH transmission with minimal risk of recrudescence [2–4].
Diagnostics play a critical role in guiding both the deployment of existing STH program resources and the implementation and evaluation of STH intervention strategies. Currently used coproscopic methods to detect and quantify STH-specific eggs, such as the Kato-Katz method, have practical advantages; test kits are inexpensive and relatively easy to perform in low-resourced field settings. They also have significant disadvantages, including moderate labor costs, lower than optimal sensitivity, and poor reproducibility in most program settings. Several academic and small-business efforts continue to develop tools with improved diagnostic performance [5–7]. However, an objective assessment on the value proposition offered by these tools has been complicated, as the diagnostic needs of a multiphased STH program have not been defined .
This report shares a user-centered framework developed by a diverse group of key opinion leaders convened over the past year by the Bill & Melinda Gates Foundation to define circumstances in which population-level diagnostic data could guide an STH program manager’s decision to transition a program to the next phase. The use-cases and companion target product profiles (TPPs) are intended to provide the community with a pathway for the research, development, evaluation, and implementation of diagnostic tools designed for STH programs. This framework can also be used to prioritize research or product development resources based on immediate and anticipated program needs.