Prevalence of Neospora caninum in cattle abortions in Northern Bavaria

232 fetuses from cattle abortions in Northern Bavaria were sent in for analysis to the department of veterinary pathology of the "Bayerischen Landesamtes fur Gesundheit und Lebensmittelsicherheit (LGL)" within a year (2005-2006) and were tested with different direct and indirect methods for Neospora caninum. Direct diagnosis of the infection was determined by histopathology, immunohistochemistry and PCR (polymerase chain reaction), ELISA (Enzyme Linked Immuno Sorbent Assay) was used for indirect analysis. 23 of the 232 cases were considered to be infected by at least one of the diagnostic techniques used. That implies that Neospora caninum is involved in 10% of abortions in Northern Bavaria. Suspicious cases could he identified by routine histopathology because of characteristic lesions - particularly in brain and heart. Typical histological lesions consisted in multifocal non-suppurative necrotizing encephalitis (13 cases) and non-purulent myocarditis (17 cases). All of these cases with lesions in the brain were confirmed by immunohistochemistry. Frequently low numbers of disease agents necessitate more (up to 4) immunohistochemical runs in some cases to verify the agent. Especially in cases of bold autolysis or mummified fetuses histology was applicable out), with restrictons, immunohistochemistry not at all. PCR is able to detect DNA of the parasit in these cases. Altogether the PCR got the most positive results. In cause of this three different techniques (conventionell PCR, Real Time SYBR Green, Real Time TaqMan) could adduce approximately same results (16, 17 and 19 positive cases). The Real Time TaqMan Technique gained slightly advantage over the two other methods. Serological tests of Neospora caninum intrinsic antibodies in fetal fluids were done in 148 cases and achieved 14 positive results (9%), but proved not to be very useful. Fetuses in early pregnancy develop partly no specific antibodies against Neospora caninum so that these cases were seronegative in spite of showing typical morphological lesions. Compared with this, 4 seropositive cases did not show any histopathological alterations. A comparison of the different methods shows that a combination of histopathology and PCR seems to be best for use in routine diagnostics.