The experimental transmission of Pneumostrongylus tenuis to caribou (Rangifer tarandus terraenovae)

Abstract

Two caribou calves (Rangifer tarandus terraenovae) were infected experimentally with Pneumostrongylus tenuis Dougherty from white-tailed deer (Odocoileus virginianus borealis). The female calf showed slight neurologic signs from the 5th to the 14th day when she died from a mycotic infection. The male calf first showed neurologic signs on the seventh day. These signs became progressively more extreme and by the 29th day, when the animal was necropsied, it showed severe locomotory ataxia with knuckling and posterior weakness. Histological study of the spinal cord of the male revealed numerous worms in all regions of the spinal cord and in the brain stem and medulla oblongata. Traumatic lesions and worms were unusually numerous in lateral and dorsal funiculi. It is suggested that the more severe neurologic signs were caused by migration of worms into funiculi from dorsal horns of grey matter. The results are discussed in relation to the management of woodland caribou in eastern North America.