Ascariasis

Soil-transmitted parasites constitute a major worm burden the world over. Ascariasis worms caused by Ascaris spp. are major parasites. There are two species, Ascaris lumbricoides and A. suum, which are difficult to distinguish. There is a host preference—A. lumbricoides for humans and A. suum for pigs, the latter being zoonotic. In places where human infection with A. lumbricoides does not occur, human infection with A suum occurs, attributed to being acquired from pig farms. However, the Centers for Disease Control and Prevention CDC (2020) reported that an estimated 807 million–1.2 billion people in the world are infected with Ascaris lumbricoides. Ascariasis occurs in tropical and subtropical areas of Asia, sub-Saharan Africa, and the Americas, particularly where open defecation prevails or faeces are used as fertilizers. Ascaris suum is found wherever pigs are found.