Moderate Neospora caninum Detection in Wild Dog Populations in Southeast Australia

Neospora caninum is an obligate intracellular protozoan parasite that causes hind-limb paralysis in dogs and abortions in cattle. Recurrent storms of abortions in cattle in Australia are estimated to cause an economic loss of AU$100 million each year, but the source of infection in cattle (i.e., via wild or domestic definitive hosts) remains to be established. We aimed to determine potential sources of horizontal transmission of N. caninum after recent evidence that wild dogs (Canis familiaris) shed N. caninum oocysts in Victoria, Australia. To determine infection levels among wild dogs, samples were collected from three sites in Victoria (n=52) in areas of high wild dog population density (Mansfield, Swifts Creek, and Tallangatta), and N. caninum detection was determined by PCR analysis of blood and duodenal samples. Based on the PCR assay of combined duodenal samples (flotation of duodenal content and just duodenal content), this study detected N. caninum in the fecal material of 11% of wild dogs in Mansfield and 21% of wild dogs in Swifts Creek. This study provides further insight into the possible role of wild dogs as a reservoir of N. caninum in Victoria.