Seroprevalence of Neospora caninum in gray wolves in Scandinavia

Transmission of the protozoan parasite Neospora caninum between wild and domestic animals has gained some interest during recent years. Because of the close relationship between gray wolf (Canis lupus) and dog it has been suggested that gray wolf is a definitive host for the parasite. The aim of this study was to estimate the seroprevalence of N. caninum in Scandinavian gray wolves and to investigate any geographical patterns of the infection. The investigation was based on blood samples collected from 109 wolves between 1998 and 2009 within the Scandinavian wolf project Skandulv. They were analysed by N. caninum iscom ELISA and those with absorbance values exceeding 0.20 were also analysed by immunoblotting. Samples that were positive in both tests were deemed positive. Four (3.7%) wolves were positive at the first sampling. They were all sampled 2005 at different locations, and were both females and males. From one male wolf three samples were collected over a 7-year period. No antibodies were detected at the first sampling in 1998 when he was approximately 8 months old but when he was sampled again 5 and 7 years later the ELISA and immunoblotting were positive. The results indicate that N. caninum infection is present in Scandinavian wolves. It is unclear how the wolves acquired the infection.