[Update on the epidemiology of hydatidosis. Hydatid echinococci: species; life cycles; epidemiologic consequences]

Human hydatidosis results from infestation by two species of Echinococcus. (1) E. vogeli, the life-cycle of which occurs in amazonian forests and involves wild canidae and cuniculidae. (2) E. granulosus, which includes two geographical groups: (a) Northern group, with two sub-species E. g borelis and E. g. canadensis, the life-cycle of which is sylvatic and that are agents of a pulmonary hydatidosis which may affect Man. (b) "European" (actually cosmopolitan) form, with two sub-species: (1) E. q. equinus (equine strain) occurring between dogs and horses and unable to infect Man; (2) E. g. granulosus, with several strains and clones according to the species of their intermediate hosts and which are the agents of synanthropic or sylvatic life-cycles. Man may enter into some of these life cycles, but not into all of them: ovine strains, chiefly, but pig and camel strains also, have a zoonotic incidence. From these data, the author emphasizes the epidemiological features of human hydatidosis, which over-runs the classical rural one, resulting from the drog-sheep life-cycle.