Infestation par les endoparasites dans différentes populations de M. marmota. Infestation by endoparasites in different Austrian populations of M. marmota.

Résumé

The gastrointestinal tracts of 162 marmots from 13 different locations were examined for endoparasites. Three populations are autochthonous, the rest has been re-introduced. The locations are arranged along a west-east gradient through the alpine region of Austria. The most common parasites were the cestode Ctenotaenia marmotae (90.1% infested) and the nematode Citellina alpina (62.3%). Beside these marmot specific parasites there was a number of different nematodes, e.g. Ascaris laevis (10.5%), Trichuris spp. (24.1%), and Trichostrongylus spp. (20.4%). There is a clear differentiation in the west-east direction. The marmot specific parasites Ctenotaenia marmotae and Citellina alpina are most abundant in the autochthonous populations. In the re-introduced populations the frequency decreases gradually to the east. The same is true for A. laevis and the genus Trichuris. Infestation with A. laevis is rather common in the autochthonous populations, but almost absent in the re-introduced populations. With Trichuris there is also a slight decrease from the west to the east. Founder events could explain the trends towards a loss of parasite species. An opposite trend is observed for the genus Trichostrongylus.