On the Helminth Fauna of the Muskrat (Ondatra zibethicus (Linnaeus, 1766)) in the Barnim District of Brandenburg State/Germany

SIMPLE SUMMARY: The knowledge of the parasite fauna in a given territory is the basis for a successful control. Publications in Germany and abroad showed that muskrats are suitable intermediate hosts for Echinococcus multilocularis, a small tapeworm of red foxes and other carnivores with zoonotic potential. After the first detection of this tapeworm in the Brandenburg state of Germany, research started to investigate the distribution of this parasite in final hosts, but the question of identifying infections in intermediate hosts remained. Introduced more than 100 years ago from north America, muskrats were shown to be suitable intermediate hosts for this parasite. In own investigations, 130 muskrats were examined for internal parasites and eleven endoparasites were found. Examination showed that muskrats trapped in the Barnim district of Brandenburg are final hosts for seven intestinal trematodes and are intermediate hosts for four tapeworms of carnivores. The larval stage of E. multilocularis was not detected. ABSTRACT: The muskrat is a neozoon species that has occupied many countries of continental North Europe after its introduction from north America as fur animals. Due to its burrowing activity it damages river and canal banks and structures of flood control. For this reason, the eradication of this alien species is recommended. Muskrats are also of parasitological interest since they can act as suitable intermediate hosts for Echinococcus multilocularis. On the other hand, little is known on the other helminths that infect muskrats. A total of 130 muskrats of different age groups trapped in different habitats in the Barnim district of the Brandenburg state by a professional hunter were examined for parasites and seven trematodes (Echinostoma sp., Notocotylus noyeri, Plagiorchis elegans, Plagiorchis arvicolae, Psilosostoma simillimum, P. spiculigerum, Opisthorchis felineus and four larval cestode species (Hydatigera taeniaeformis, Taenia martis, Taenia polyacantha, Taenia crassiceps) were detected. Larval stages of E. multilocularis were not found. O. felineus was found for the first time in muskrats in Germany. All the named parasites were present in Europe prior to the introduction of muskrats. With a prevalence of 48.9%, Strobilocercus fasciolaris, the larval stage of the cat tapeworm, H. taeniaeformis, was the most frequent parasite found in adult muskrats.