[Detection of the larva of Taenia multilocularis in 2 voles (Microtus arvalis and Clethrionomys glareolus) in a focus of alveolar echinococcosis in the Massif Central (France)].

Small wild rodents were collected and examined during 1983-1984 to investigate parasite-host relationships of Echinococcus multilocularis in one habitat suitable for red foxes of Auvergne (France). The natural infestation of the liver of two different voles, Microtus arvalis and Clethrionomys glareolus, by the larval stage of the cestode is recorded for the first time. In the both cases, the larvae were fully developed and numerous protoscolices were present with some calcareous corpuscules; the expansion of the larvae involved several hepatic lobes in Microtus and was restricted to a single lobe in Clethrionomys. Epidemiological consequences of the receptivity of the two hosts are not yet investigated in the field. However several species of voles inhabiting the same endemic area and which are receptive to the larval stage of alveolar echinococcosis should be a favourable factor of durability for the cestodiasis of the foxes; so the parasite is able of surviving the cyclic and considerable but not simultaneous fluctuations of the three populations of voles which are locally implicated in the zoonosis: M. arvalis, C. glareolus and Arvicola terrestris, by changing from one species to the others.