An Update on the Geohelminths: Ascaris lumbricoides, Hookworms, Trichuris trichiura, and Strongyloides stercoralis.

Geohelminths remain prevalent throughout the developing world where levels of sanitation, personal hygiene, and maternal education are low. The five species of nematodes responsible for the bulk of disease are Ascaris lumbricoides, the hookworms Ancylostoma duodenale and Necator americanus, Trichuris trichiura, and Strongyloides stercoralis. Geohelminths are acquired through ingestion of fecally contaminated food or water or through contact with infected soil. In developing countries, infection with more than one nematode species and high worm burdens are common. The morbidity is substantial, particularly among children, and deaths occur. Geohelminthic infections are encountered in industrialized countries among immigrants and long-term travelers who have lived in endemic regions where sanitation is poor, and occasionally following autochthonous transmission.