Parasites of the Northern River Otter (Lontra canadensis) in Virginia, USA
IAAAM 2009
Morgan Agnew1; Anne M. Zajac1; Stephen A. Smith1; Mike Fies2
1Virginia-Maryland Regional College of Veterinary Medicine, Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA; 2Virginia Department of Game and Inland Fisheries, Wildlife Division, Verona, VA, USA


Sixty-seven (28 females and 39 males) northern river otters, Lontra canadensis, were trapped in 16 counties in Virginia from December 2006 until February 2007 and examined for parasitic helminth infection. The gastrointestinal tracts and hearts were removed from the abdominal and thoracic cavity of each animal, and the heart, stomach and intestinal contents collected separately and preserved in 10% formalin. Parasites were found in 67% of the digestive tracts. Thirty-seven percent of the stomach samples and 60% of the intestinal content samples contained parasites. Three species of trematodes, one species of cestode, one species of acanthocephalan and one species of nematode in both its larval and adult stages were identified in the gastrointestinal tracts of the otters. Adult Baschkirovitrema incrassatum were identified in 12% of the intestinal contents and 12% of the stomach contents samples. Combined, this trematode was present in 19% of the gastrointestinal tracts of the otters. Several adult Enhydridiplostomum sp. were collected from the intestine of one otter. Other trematodes recovered from the otters were strigeoid metacercariae of the neascus type and several larval Clinostomum sp. The tapeworm Diphyllobothrium sp. was identified in one of the stomach samples, and an unidentified acanthocephalan was isolated from the intestinal contents of one otter. Strongyloides sp. in the larval form was identified in 58% of the otters examined and Strongyloides sp. adults were identified in 10% of the otters examined. Strongyloides sp. was identified in its larval stage in 16% of the stomach samples and 54% of the intestinal contents, while adult Strongyloides sp. was identified in 3% of the stomach samples and 7% of the intestinal content samples. None of the hearts examined showed the presence of the heartworm parasite, Dirofilaria immitis. The number of parasites identified in this study suggests that the river systems in Virginia support a more diverse assemblage of species than river systems in Tennessee, but a less diverse assemblage of species than river systems in the Pacific northwest.1,2


1.  Hoberg E.P., C.J. Henny, O.R. Hedstrom, and R.A. Grove. 1997. Intestinal helminths of river otters (Lutra canadensis) from the Pacific Northwest. J Parasit 83: 105-110.

2.  Kollars T.M., R.E. Lizotte, and W.E. Wilhelm. 1997. Gastrointestinal helminths in the river otter (Lutra canadensis) in Tennessee. J Parasit 83: 158-160.


Speaker Information
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Stephen A. Smith
Virginia-Maryland Regional College of Veterinary Medicine
Virginia Polytechnic Institute and State University
Blacksburg, VA, USA