PARELAPHOSTRONGYLUS TENUIS IN TERRESTRIAL GASTROPODS FROM WHITE-TAILED DEER WINTER AND SUMMER RANGE IN NORTHERN NEW BRUNSWICK

Abstract

The prevalence of Parelaphostrongylus tenuis infection was compared in terrestrial gastropods from white-tailed deer ( Odocoileus virginianus) summer range and wintering yards in northern New Brunswick during summer, 1995. Of 10,343 snails and slugs examined, only 4 were infected with 1 to 3 P. tenuis third-stage larvae (0.04%); all of these (the snail Discus cronkhitei and the slugs Deroceras laeve and Arion sp.) were collected from the deer yard. The effective frequency of infection in the wintering yard was 0.09%  and zero (undetectable) on summer range. Mean gastropod densities on summer and winter range did not differ (8.3/m² and 6.2/m², respectively). We suggest that the higher frequency of infection in the winter yard results from seasonally increased deer usage of these habitat types, and that moose (Alces alees) using such yards during snow-free periods will have increased risk of infection with P. tenuis. The relatively low prevalence of infection observed in gastropod intermediate hosts may reflect the effect of an unseasonably dry spring and summer on the transmission of P. tenuis.