Metazoan Parasites of the Muskrat, Ondatra Zibethica Cinnamominus, From the English Coulee Grand Forks County, North Dakota

During the fall of 1966 and the spring of 1967, 55 muskrats were trapped along the reaches of the English Coulee, Grand Forks County, North Dakota. These muskrats were necropsied and all ectoparasites and endoparasites collected. The parasites were stained and identified and the number of worms counted to discern the parasite burden. Eight species of parasites were found. The only ectoparasite encountered was Laelaps multispinosus (89.09 per cent incidence). Four species of trematodes were identified as Echinostoma revolutum (34.54 per cent), Quinqueserialis quinqueserialis (47.27 per cent), Notocotylus urbanensis (41.81 per cent), and Plagiorchis proximus (14.54 per cent). Two species of cestodes were found. These were Hymenolepis evaginata (3.63 per cent) and the larval stage of Hydatigera taeniaeformis (16.36 per cent). Only one specimen of a nematode was found. This was Trichuris opaca (1.81 per cent). It was concluded that the worm burden was not sufficient to cause disease, and no obvious pathology was found in any of the muskrats examined