Monitoring schistosomiasis and sanitation interventions—the potential of environmental DNA

Transmission of schistosomiasis, a human parasitic disease, is intrinsically linked to inadequate water, sanitation, and hygiene (WASH) facilities and/or their use. The mainstay of control is population‐based chemotherapy. Globally, each year, 240 million people are estimated to require this preventative treatment. However, for long‐term, sustainable control of this disease, supplementary WASH improvements are required to prevent (re)infection of humans (provision of safe water) and transmission from humans to the environment (improved sanitation). While there is established methodology for monitoring transmission in human populations, presently methods for monitoring the impact of WASH interventions, in particular sanitation, on environmental transmission are lacking. Development of such becomes paramount as integrated control programs combine drug treatments with enhanced WASH facilities and behavior change interventions, with uptake likely correlated to a reduction in fecal matter, and schistosome eggs, in the environment but any impact on infection levels in humans taking longer to become apparent. This article reports and critiques the methods currently used to monitor schistosomiasis in freshwater and soil environments and explores how environmental DNA could be used to better understand and monitor environmental contamination in relation to sanitation. Stronger evidence is required to understand how different sanitation interventions serve to limit the environmental transmission of the parasite and their relative effectiveness in preventing disease