A Survey of Helminths of the Muskrat, Ondatra z. zibethica Miller, 1912, in Portage County, Ohio

Abstract

From 130 muskrats collected at 13 sites in Portage County, Ohio, 10 species of trematodes, two species of cestodes, five species of nematodes, and one genus of acanthocephalans were identified. The finding of Corynosoma sp. represents the first record of this acanthocephalan genus from North American muskrats. The recovery of the nematode Longistriata dalrymplei Dikmans, 1935 and of the trematode Mediogonimus ovilacus Woodhead and Malewitz, 1936 constitute second reports of these species. A table summarizing the published literature (1951-66) on helminths from North American muskrats is included. Numerous helminthological surveys concerning the muskrat Ondatra z. zibethica Miller, 1912 have been made in North America. Several reports have summarized the literature up to 1951 (Meyer and Reilly, 1950; Knight, 1951). As an aid to individuals currently conducting similar research, Table I lists the literature in North America from 1951 through 1966. Prior to this report, the only published survey of helminths of Ohio muskrats was that by Rausch (1946). His investigation covered the period from March 1943 to March 1945. Seventy muskrats were examined from seven scattered Ohio localities. Four species of trematodes (Echinostomum coalitum Barker and Beaver, 1915; Notocotylus quinqtieserialis Barker and Beaver, 1915; Wardius zibethicus Barker and Beaver, 1915; and Plagiorchis proximus Barker and Beaver, 1915), one species of cestode (Taenia taeniaeformis Batsch, 1786), two species of nematodes (Capillaria ransomia Barker and Noyes, 1915 and Trichuris opaca Barker and Noyes, 1915), and one genus of cestodes (Hymenolepis) were identified. The objective of our investigation was to determine if these same species, as well as others, parasitized muskrats in Portage County, Ohio. MATERIALS AND METHODS During the 1963 and 1964 Ohio trapping seasons, 13 collection sites were established in Portage County. These included portions of eight lakes and ponds, the Mahoning and Cuyahoga rivers and three swampy-creek areas. Fur dealers and trapReceived for publication 17 February 1967. * From a thesis submitted to the Graduate School of Kent State University in partial fulfillment of the requirements for the degree of Master of Arts. pers were the primary sources of skinned carcasses, but 30 animals were trapped by one of us (Beckett). Ten muskrats from each collection site were data-tagged, frozen, and stored at -20 C until ready for study. All of the worms recovered were fixed in A. F. A. Delafield's hematoxylin and Mayer's paracarmine were used to stain cestodes and trematodes. Fastgreen in 95% ethyl alcohol was used to counterstain the ventral glands of monostomes and the cephalic spines of members of the Echinostomatidae. Acanthocephalans were stained with Delafield's-Ehrlich's hematoxylin. Nematodes were cleared in glycerine and mounted in glycerine jelly. RESULTS AND DISCUSSION A total of 130 muskrats, comprising 68 males and 62 females, were examined from the 13 collection sites. Ten species of trematodes, two species of cestodes, five species of nematodes, and one genus of acanthocephalans were identified (Table II). Only those helminths identified during this survey and reported infrequently from North American muskrats will be discussed.