Controlling soil-transmitted helminths: time to think inside the box?

Abstract

Soil-transmitted helminths (STH) refer to several parasitic nematode species that infect over 1 billion people worldwide. Infections with Ascaris lumbricoides , Trichuris trichiura , and the hookworms Necator americanus and Ancylostoma duodenale cause significant morbidity in more than 450 million people, primarily children and pregnant women, resulting in over 39 million disability-adjusted life years lost. Considerable effort and resources have been, and continue to be, spent on top-down, medical-based programs to control STH infections, with little success. This review discusses the problems with these methods and proposes a new emphasis on sustainable, long-term investments in sanitation-based approaches using improved latrines (the "box") to provide bottom-up, culturally appropriate, and economically desirable solutions to STH control in endemic areas. One such approach is the use of biogas technology. Waste undergoes fermentation in specially designed septic systems, generating a methane gas mixture ("biogas") that can be burned to augment or replace household energy needs such as cooking and light generation. Also, the effluent from the fermentation chamber provides a high quality, nitrogen rich fertilizer. Using China as an example, the use of biogas technology as a solution to rural sanitation and energy problems is described, and its advantages over current strategies of mass drug administration and vaccination for STH control are highlighted.