Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2007
Publication Date: 5/1/2007
Citation: Wapenaar, W., Barkema, H.W., Schares, G., Rouvinen-Watt, K., Zeijlemaker, L., Poorter, B., O’Handley, R.M., Kwok, O.C., Dubey, J.P. 2007. Evaluation of four serological techniques to determine the seroprevalence of Neospora caninum in foxes (Vulpes vulpes) and coyotes (Canis latrans) on Prince Edward Island, Canada. Veterinary Parasitology. 145:51-58. Interpretive Summary: Neospora caninum is a single-celled parasite. It causes abortion in cattle and paralysis in companion animals. It is the most important cause of abortion in dairy cattle. Dogs and coyotes are its definitive hosts and main reservoirs of infection. This parasite is transmitted efficiently from the cow to the calf transplacentally. Scientists at the Beltsville Agricultural Research Center and from Prince Edward Island, Canada report prevalence of Neospora in wild carnivores.The results will be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: The objectives of this study were 1) to evaluate the performance and agreement of serological assays (ELISA, IFAT, N. caninum agglutination test and immunoblot) using reference sera and field sera from foxes and coyotes and 2) to estimate the N. caninum seroprevalence in foxes and coyotes on Prince Edward Island, Canada. With fox and coyote reference sera the test performance of the ELISA, IFAT and IB was excellent (100% sensitivity and specificity). NAT showed a low sensitivity (50%). Serum was collected from 201 coyotes and 271 foxes. The seroprevalence observed in the different assays ranged from 0.5 to 14.0% in coyotes and 1.1 to 34.8% in foxes. The seroprevalence, when taking more than 1 test positive as cut-off value was 3.3 and 1.1% for coyotes and foxes respectively. From the N. caninum-positive group, all coyotes were older than 3 years. Agreement among assays (measured as prevalence-adjusted bias-adjusted kappa) using the field sera ranged from 0.17 to 0.97. Best agreement was observed between ELISA and IFAT, poor agreement was observed between NAT and the other assays. Positive agreement was moderate to poor among all assays utilized in this study. Although the seroprevalence observed was low, N. caninum antibodies are present in foxes and coyotes on Prince Edward Island and their role in the N. caninum epidemiology needs further study.