NEOSPORA-CANINUM CAUSES ABORTIONS IN A CA TTLE HERD IN NORTH-RHINE-WESTPHALIA

In a cattle herd in North Rhine-Westphalia a series of eight abortions occurred between 15th August and 14th October, 1996. Four of the abor ted fetuses were histopathologically, virologically, bacteriologically and parasitologically examined. A multifocal necrotising encephalitis was observed in two fetuses. In addition, the liver of two fetuses an d the placenta of one fetus contained infected foci. In three fetuses protozoan stages were detected which were identified as N. caninum by immunohistochemistry. A polymerase chain reaction conducted with histo logical material revealed N. caninum-DNA in the placenta of an aborted fetus. When seven cows that had aborted were tested for antibodies di rected against N. caninum, six animals were positive by immunofluoresc ence and all seven by immunoblotting. The serological examination of t he entire herd revealed a high herd seroprevalence of antibodies direc ted against N. caninum. Potential modes of infection with N. caninum i n the herd are discussed, in particular the possibility of exposure to a point source (definitive host).