Ascariasis is the disease produced by infestation with the roundworm Ascaris lumbricoides, also known as the maw-worm. Superﬁcially it resembles a large earthworm: the male measures about 17 cm (7 inches) and the female 23 cm (9 inches) in length. Ascariasis is a dirt disease, most prevalent where sanitation and cleanliness are lacking, particularly in the tropics and subtropics. Consumption of food contaminated by the ova (eggs), especially salad vegetables, is the commonest cause of infection. In children, infection is commonly acquired by crawling or playing on contaminated earth, and then sucking their ﬁngers. After a complicated life-cycle in the body the adult worms end up in the intestines, whence they may be passed in the stools. A light infection may cause no symptoms. A heavy infection may lead to colic, or even obstruction of the gut. Occasionally a worm may wander into the stomach and be vomited up.
Treatment Mebendazole is the drug of choice in the UK, being given as a single dose. It should be combined with hygienic measures to break the cycle of autoinfection. All members of the family require treatment. Other ANTHELMINTICS include piperazine and pyrantel.