Untersuchungen zur Rolle des Rotfuchses (Vulpes vulpes) als möglicher Endwirt von Neospora caninum

Neospora (N.) caninum is a protozoan parasite which is regarded as a major cause of abortion in cattle. Dogs and coyotes are definitive hosts of N. caninum which may shed environmentally resistant stages, oocysts, in their feces. Epidemiological studies in Germany showed that the presence of dogs increased the risk of a bovine herd to be N. caninum-positive in a bulk-milk ELISA test. However, there were also N. caninum-positive herds where dogs were not kept together with cattle. This leads to the question whether canids other than dogs, e.g. foxes, might be involved in the horizontal transmission of N. caninum. Therefore, the aim of our examinations in wild animals was to find out whether there are indications for a sylvatic cycle with foxes as definitive hosts and deer, roe deer and wild mice as intermediate hosts of N. caninum. A total of 2191 fecal samples from foxes from Baden-Wurttemberg were examined. The samples had been collected in the northern parts of Baden-Wurttemberg and in the Swabian Alp. 65 of these samples contained structures which resembled those of coccidian oocysts. In 13 of these 65 samples coccidian DNA was detected using a 18S rNRA gene based polymerase chain reaction (PCR). The examination of the 65 samples in a N. caninum-specific PCR revealed no positive result. Hammondia (H.) heydorni-DNA was detected in two samples. In addition, brain samples from 528 foxes, 224 wild mice, 16 deer and roe deer as well as from 1 wild boar were examined for the presence of N. caninum DNA by real time PCR. All samples tested negative by PCR in conclusion, our study yielded no evidence indicating that the examined animals were part of a sylvatic cycle for N. caninum.