FURTHER EXPERIMENTAL STUDIES OF PNEUMOSTRONGYLUS TENUIS IN CERVIDS

Two young wapiti (Cervus canadensis nelsoni) and a female mule deer fawn (Odocoileus hemionus hemionus) were infected experimentally with Pneumostrongylus tenuis from white-tailed deer (Odocoileus virginianus borealis). The male wapiti showed only slight clinical signs after infection, and first-stage larvae appeared in its faeces 92 days later. The female wapiti showed severe neurological signs that terminated in general paralysis on the 54th day. The mule deer showed severe neurologic signs and died of paralysis on the 62nd day. Numerous worms were found in the subdural space and neural parenchyma, especially in the dorsal horns of grey matter, of the female wapiti and the mule deer. Traumatic damage in the dorsal horns was extensive, especially in the wapiti. Histopathologic findings were similar to those reported earlier in moose calves (Alces americana americana) infected with P. tenuis. Study of worms recovered from experimentally infected cervids indicates that P. tenuis develops similarity in white-tailed deer, moose, wapiti, and mule deer although in the first species it causes little damage to the central nervous system. The possibility that P. tenuis could become established in wapiti introduced into eastern North America is noted.