- A tiny parasitic tapeworm. The larval stage of this tapeworm can cause human disease. There are three forms of Echinococcus that affect humans — E. (Echinococcus) granulosus, E. multilocularis, and E. vogeli — and each has a different geographic distribution and tends to cause a different pattern of disease. E. granulosus is common in areas where livestock is raised in association with dogs — in Australia and New Zealand, Argentina and Chile, Africa, E. Europe, the Middle East, and the Mediterranean region, especially Lebanon and Greece — and causes unilocular cysts. E. multilocularis is found in Alpine, sub-Arctic, or Arctic regions — including Canada, the United States, and central and northern Europe and Asia — and causes multilocular lung disease known as alveolar hydatid disease (AHD).
* * *A genus of very small taeniid tapeworms, two to five segments in adult worms; adults are found in various carnivores but not in humans; larvae, in the form of hydatid cysts, are found in the liver and other organs of ruminants, pigs, horses, rodents, and, under certain epidemiologic circumstances, humans ( e.g., sheep herders living closely with their infected dogs). [echino- + G. kokkos, a berry]- E. granulosus hydatid tapeworm, a species in which adults infect canids and the larval form (osseous and unilocular hydatid cysts) infects sheep and other ruminants, pigs, and horses; may also occur in humans, giving rise to a large cyst in the liver or other organs and tissues.- E. multilocularis a north temperate and Arctic species of tapeworm that occurs, in the adult form, in foxes; the larva (alveolar hydatid cyst) is found in the liver of microtine rodents and in humans; it produces a proliferative, often slow-growing cyst in the liver that, in humans, is usually fatal.- E. vogeli a species reported from humid tropical forests of Panama and northern South America causing a polycystic form of human hydatid disease intermediate between cystic and alveolar hydatid disease; the typical cycle involves domestic dogs and wild canids as host of the adult tapeworm, and rodents such as the paca (Cuniculus paca) as the intermediate host for the cystic form.
* * *echi·no·coc·cus -nə-'käk-əs n1) cap a genus of tapeworms of the family Taeniidae that alternate a minute adult living as a harmless commensal in the intestine of dogs and other carnivores with a hydatid larva invading tissues esp. of the liver of cattle, sheep, swine, and humans, and acting as a serious often fatal pathogen
* * *n.a genus of small parasitic tapeworms that reach a maximum length of only 8 mm. Adults are found in the intestines of dogs, wolves, or jackals. If the eggs are swallowed by a human, who can act as a secondary host, the resulting larvae penetrate the intestine and settle in the lungs, liver, or brain to form large cysts, usually 5-10 cm in diameter (see hydatid disease). Two species causing this condition are E. granulosus and E. multilocularis.
* * *Echi·no·coc·cus (e-ki″no-kokґəs) [echino- + Gr. kokkos berry] a genus of small tapeworms of the family Taeniidae.
Medical dictionary. 2011.