Occurrence of Neospora caninum infections in cattle of Rhineland-Palatinate (Germany)

Objective: Neospora caninum belongs to the most frequently diagnosed infectious causes of bovine abortion. In cattle herds, infections with N. caninum may result in permanently increased abortion rates or abortion outbreaks. The aims of the here summarized studies were to obtain an overview over the distribution of bovine N. caninum infections in the German state of Rhineland-Palatinate and to identify putative risk factors for the introduction of the infection into herds. Material and methods: In the year 2000 90% (n = 3260) of the dairy herds of the state of Rhineland-Palatinate were examined by a bulk milk ELISA. Results: Clear regional differences were observed. In the districts and cities located in the south of Rhineland-Palatinate more than 15% of the herds were tested positive while in the north-western districts the prevalence was partially below 5%. A risk factor analysis to which more than 1200 farmers contributed was conducted during the same period of time. It indicates that farm dogs represent the most important risk factor. However, also the density of dogs kept in the municipality of farm location appeared as a risk factor for herds to be bulk milk positive. Conclusions and clinical relevance: The results of the summarized studies provide evidence that, in addition to farm dogs, also dogs kept in the surroundings of farms represent a source for the introduction of N. caninum infections into cattle herds. The observations can explain why N. caninum associated abortions also occur on German farms that do not keep dogs.