Etiology Human trichinellosis (also called trichinosis ) is caused by consumption of meat containing encysted larvae of Trichinella spiralis, a tissue-dwelling nematode with a worldwide distribution. After ingestion of raw or inadequately cooked meat from pigs (or other commercial meat…
Etiology Most cases of human toxocariasis are caused by the dog roundworm , Toxocara canis. Adult female T. canis worms live in the intestinal tracts of young puppies and their lactating mothers. Large numbers of eggs are passed in the…
Onchocerciasis (Onchocerca Volvulus) Infection with Onchocerca volvulus leads to onchocerciasis or river blindness . Onchocerciasis occurs primarily in West Africa but also in Central and East Africa and is the world's 2nd leading infectious cause of blindness. There have been…
Etiology The filarial worms Brugia malayi ( Malayan filariasis ), Brugia timori, and Wuchereria bancrofti ( bancroftian filariasis ) are threadlike nematodes that cause similar infections. Infective larvae are introduced into humans during blood feeding by the mosquito vector. Over…
Etiology Strongyloidiasis is caused by the nematode, or roundworm, Strongyloides stercoralis. Only adult female worms inhabit the small intestine. The nematode reproduces in the human host by parthenogenesis and releases eggs containing mature larvae into the intestinal lumen. Rhabditiform larvae…
Etiology The cause of enterobiasis, or pinworm infection, is Enterobius vermicularis, which is a small (1 cm in length), white, threadlike nematode, or roundworm, that typically inhabits the cecum, appendix, and adjacent areas of the ileum and ascending colon. Gravid females…
Etiology Trichuriasis is caused by the whipworm , Trichuris trichiura, a nematode, or roundworm, that inhabits the cecum and ascending colon. The principal hosts of T. trichiura are humans, who acquire infection by ingesting embryonated, barrel-shaped eggs ( Fig. 319.1…
Etiology Ascariasis is caused by the nematode, or roundworm , Ascaris lumbricoides. Adult worms of A. lumbricoides inhabit the lumen of the small intestine. The reproductive potential of Ascaris is prodigious; a gravid female worm produces 200,000 eggs per day.…
Tissue-dwelling nematode (roundworm) infections are widely distributed throughout the world. The health and socioeconomic impacts of these infections are greatest in resource-poor settings in the tropics and subtropics, although populations in temperate and industrialized regions of the world continue to…