Data and statistics
The causal agent of soil-transmitted helminthiasis is any of the following worms: Ascaris lumbricoides, Trichuris trichiura and hookworms. Recent estimates suggest that A. lumbricoides infects over 1 billion people; T. trichiura, 795 million; and hookworms (Ancylostoma duodenale and Necator americanus), 740 million. The greatest numbers of infections occur in sub-Saharan Africa, the Americas and East Asia (including China). Infection is caused by ingestion of eggs from contaminated soil (A. lumbricoides and T. trichiura) or by active penetration of the skin by larvae in the soil (hookworms).
Soil-transmitted helminthiases produce a wide range of symptoms – including intestinal manifestations (diarrhoea, abdominal pain), general malaise, anaemia and weakness – that may affect people’s working and learning capacities and impair physical growth. Hookworms cause chronic intestinal blood loss that results in anaemia.