Experimental Elaphostrongylus cervi infection in moose (Alces alces).

An 8-week-old male moose calf was inoculated with 360 infective third-stage larvae (L3) of E. cervi. The calf started to expel first-stage larvae (L1) of E. cervi in faeces 63 days after inoculation. The highest faecal larval count of 1,920 L1 per gram faeces was recorded 133 days post inoculation. Clinically, intermittent lameness, mild ataxia and general stiffness were observed over a 3 months’ period from day 75 after inoculation. The symptoms were moderate, faded gradually and were not seen during the last three weeks of the observation period. The calf had a good appetite and the bodyweight increased continuously throughout the experiment. On day 202 after inoculation the calf was euthanized and autopsied. Adult E. cervi were found in the epidural space of the central nervous system (CNS) and in skeletal muscles. Oedema, haemorrhages, discolouration and extensive inflammatory reactions were observed in the fat and loose connective tissue of the epidural space between the 5 th cervical vertebra and cauda equina. Nematodes or lesions indicating nematode infestation could not be demonstrated in the leptomeninges or in the neural parenchyma of the CNS. Numerous eggs and larvae of E. cervi associated with moderate pathological changes were observed in the lungs.