Elaphostrongylus cervi infection in moose (Alces alces). Prevalence and pathological changes in relation to age and season

The prevalence of Elaphostrongylus cervi infection in 8–10-month-old moose calves shot in March/April in Southeastern Norway was studied. The prevalence was compared with the prevalence of infection in 4–6- and 16–18-month-old animals shot in September/October. The location of adult worms, the pathological changes which they caused within the central nervous system and their pathogenicity, were also studied. Examination of 54 8–10-month-old moose calves revealed that 46 (85 %) of the calves were infected with E. cervi. Thus a considerable proportion of the calves in the areas investigated obviously became infected with E. cervi during their first summer season. The prevalence of infection seemed to decline from the age of 8–10 months in spring till the age of 16–18 months in autumn. No difference in mean carcass weight was found between infected and non-infected calves of comparable age. Within the central nervous system adult E. cervi and associated pathological changes were found exclusively in the epidural space. The high prevalence of E. cervi infection, the insignificant differences in general condition between infected and non-infected calves and the epidural location of adult worms suggest, when considered together, that E. cervi infection in general is only moderately pathogenic in moose.The lungworm Varestrongylus alces was found in 18 of 70 moose calves examined (26 %).