Distribution, prevalence and intensity of Trichinella spiralis infection in furbearing mammals of Pennsylvania.

Tongues from 1,170 raccoons, 384 opossums, 201 muskrats, 168 foxes (red and grey), 51 skunks, and 17 mink from Pennsylvania were examined for Trichinella spiralis larvae by peptic digestion. The overall prevalence of T. spiralis infection was 3.2%, varying in the carnivores from 2.6% in raccoons to 15.1% in red foxes; no muskrats were infected. Prevalence varied regionally, being higher west of the Susquehanna River, where, in the Ridge and Valley Province, it reached 9%. The larval densities varied greatly as reflected by the overall geometric mean number of larvae per gram of muscle (LPG) of 18.5 and the comparable arithmetic mean LPG of 113.3. No geographic, sex, or species-related differences in the intensity of infection were demonstrated.