Soil-Transmitted Helminths

Soil-transmitted helminthiases are caused by infection with intestinal parasites (Ascaris lumbricoides and Trichuris trichiura), hookworms (Necator americanus and Ancylostoma duodenale) and roundworms (Strongyloides stercoralis).

Globally over 600 million people are estimated to be infected by S. stercoralis; however, since also this parasite is transmitted in areas where sanitation is poor, its geographical distribution overlaps with the one of the other soil-transmitted helminthiases.

Soil-transmitted helminth (STH) infections are among the most common infections worldwide with an estimated 1.5 billion infected people or 24% of the world's population. These infections affect the poorest and most deprived communities with poor access to clean water, sanitation and hygiene in tropical and subtropical areas, with the highest prevalence reported from sub-Saharan Africa, China, South America and Asia.

They are transmitted by eggs present in human feces, which in turn contaminate soil in areas where sanitation is poor. Over 260 million preschool-age children, 654 million school-age children, 108 million adolescent girls and 138.8 million pregnant and lactating women live in areas where these parasites are intensively transmitted, and are in need of treatment and preventive interventions.