Hookworm diseases are helminthic, caused by parasites in the human intestine, and can lead to iron-deficiency anaemia, vomiting, and various other debilitating effects. The parasitic roundworm Ancylostoma duodenal causes ancyclostomiasis; Necator americanus causes necatoriasis. Infection occurs mainly through vegetables, fruits, etc., which are contaminated by soil containing the larvae, deposited there from the faeces of an infected person. Nectoriasis infection can also be caused by going barefoot, because nector larvae enter the host through the skin. The dog hookworm A caninum can also infect humans.
Hookworm diseases are particularly widespread in tropical and subtropical zones, especially Latin America, Africa and Asia.