Intestinal worms

Soil-transmitted helminths

Soil-transmitted helminths

A young child infected with Soil-transmitted helminths
© SCI/Elisa Bosque-Oliva


Soil-transmitted helminths common known as intestinal worms, are the most common infections worldwide affecting the most deprived communities.
The causal agent of soil-transmitted helminthiasis is any of the following worms: Ascaris lumbricoides, Trichuris trichiura and the 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 soil-transmitted helminth infections occur in sub-Saharan Africa, the Americas, China and east Asia. 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 helminths produce a wide range of symptoms including intestinal manifestations (diarrhoea, abdominal pain), general malaise and weakness, that may affect working and learning capacities and impair physical growth. Hookworms cause chronic intestinal blood loss that results in anaemia.

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