What
Soil-transmitted helminths (STH) — such as the large roundworm (Ascaris lumbricoides), hookworms and the whipworm (Trichuris trichiura) — are intestinal worms that are transmitted through fecal contamination of the environment.
Who
STH infections are among the most common infections worldwide. An estimated 1 billion, 650 million and 750 million people are infected with Ascaris, hookworm and Trichuris, respectively. Children are most severely impacted by these parasites.
Where
Areas with warm and moist climates and where sanitation and hygiene are poor, with the highest prevalence reported from sub-Saharan Africa, South America and many countries in Asia.
Symptoms
STH infections impair growth, impede cognitive development and cause severe anemia.
DOLF Project’s contributions
Drugs used in mass drug administration (MDA) for lymphatic filariasis or onchocerciasis are also active against STH infections, and STH suppression is an important ancillary benefit of MDA programs for lymphatic filariasis. Conventional deworming campaigns usually target school-aged children; this provides temporary benefits for children with limited effects on transmission. On the other hand, MDA for onchocerciasis and LF treats a majority of the population (adults and children), which may have the added benefit of decreasing STH transmission.
The DOLF Project has studied the effects of treating total populations to test whether MDA can reduce STH infection intensities and reinfection rates. Our studies in five countries have shown that MDA has a strong beneficial impact on hookworm infections in populations, with less lasting effects on Ascaris or whipworm.
Additional information
Learn more about soil transmitted helminths from the Centers for Disease Control and Prevention and the World Health Organization.