EXPERIMENTAL INFECTION OF MOOSE (ALCES ALCES) WITH ELAPHOSTRONGYLUS SPP. (NEMATODA, PROTOSTRONGYLIDAE) ORIGINATING FROM REINDEER (RANGIFER TARANDUS) AND MOOSE, WITH SPECIAL EMPHASIS ON CLINICAL SIGNS, GROSS- AND MICROSCOPIC LESIONS, AND PREDILECTION SITES

Abstract

Captive moose calves (Alces alces) were used to study symptoms of Elaphostrongylus infections that affect moose and reindeer (Rangifer tarandus) in Scandinavia. Seven calves were infected experimentally with Elaphostrongylus alces larvae and three with E. rangiferi larvae. Both parasites produced neurological and behavioral symptoms in calves. The E. alces animals showed mild to severe neurological signs and moderate pathological changes, mainly in the meninges and the peripheral nervous system. Other symptoms were posterior weakness, clockwise circling, and inwards bending of the hind legs. The E. rangiferi animals showed severe neurological signs and paralysis with mild to prominent pathological changes in the central nervous system; behavioral symptoms included legs kept wide apart, weakness, gait incoordination, and reluctance to rise. In general, the severity of symptoms was related to the parasitic dosage and whether the host was normal or aberrant. The symptoms and lesions identified here should aid in identifying the cause and extent of these parasites in mortality of wild moose typically observed at or near death.