Role of DNA-detection–based tools for monitoring the soil-transmitted helminth treatment response in drug-efficacy trials

Abstract

More than 1 billion people have been reported to be infected with at least one soil-transmitted helminth (STH) worldwide, according to the last published report of the World Health Organization (WHO). WHO guidelines for STH control mainly encompass periodic administration of benzimidazoles (albendazole or mebendazole) to at-risk people of the endemic areas. However, extended use of benzimidazoles could entail a great selection pressure for parasitic-resistant strains. In veterinary medicine, anthelmintic resistance in gastrointestinal nematodes has been developed in response to their excessive use, and it is currently considered a serious threat to livestock health and welfare. In humans, the estimated efficacy of albendazole and mebendazole against Trichuris trichiura has been observed to significantly decrease over time. This observed decrement in drug efficacy could be due to the development of anthelmintic resistance (among other reasons such as drug quality and administration, the increasing of drug-efficacy studies, improvements in sensitivity of diagnostic tools after treatment, etc) after years of mass drug-administration campaigns, which is one of the major concerns in STH control. Monitoring anthelmintic efficacy trials have been traditionally done by microscopic approaches, although it is well known that microscopy’s sensitivity may be insufficient in this context. We think that DNA-detection–based tools represent an accurate alternative to parasitological methods, and they should be evaluated and validated not only for monitoring worm burden before and after treatment but also for detecting genetic markers related to anthelmintic resistance.