DISTRIBUTION OF ELAPHOSTONGYLINE NEMATODES (METASTRONGYLOIDEA: PROTOSTRONGYLIDAE) IN CERVIDAE AND POSSIBLE EFFECTS OF MOVING RANGIFER SPP. INTO AND WITHIN NORTH AMERICA

Abstract

Four species of elaphostronglyine nematodes presently are known from cervids of North America. Parelaphostrongylus ocodoilei occurs in mule deer, Columbian black-tailed deer, caribou, and mountain goat in western Canada and United States. Parelaphostrongylus tenuis occurs in white-tailed deer throughout much of the range of this host in eastern North America. It also occurs in the free-ranging wapiti in central Manitoba and is a pathogen of moose where there range overlaps with white-tailed deer in eastern North America. Parelaphostrongylus andersoni, first reported in a few disjunct populations of white-tailed deer in the eastern United States and western Canada, also occurs in caribou in northcentral and eastern Canada, including Newfoundland. Elaphostrongylus cervi is known in North America only from caribou in central Newfoundland where it was probably introduced with reindeer brought from Norway. Earlier speculation that E. cervi also occurs in mainland Canada was based on the presence of dorsal-spined larvae in caribou feces. Specific diagnosis of first-stage larvae is impossible but most of these earlier reports are now thought more likely to have been P. andersoni infections. Possible exceptions are reports of unusually long larvae (means >400μ) from woodland caribou in northeastern Alberta and from the Meally Mountain herd, Labrador. There have been opportunities for E. cervi to spread to mainland Canada with introduced reindeer and caribou but there is, as yet, no conclusive evidence that it has become established outside of Newfoundland.