TDK conference 2014

Coxiella burnetii and members of the Chlamydiales order are Gram negative, intracellular bacteria. They are potential abortive agents in ruminants but they are also important due to their zoonotic character. Namely, they can develop clinical symptoms in humans as well.

The aim of this study was to estimate the occurrence and the importance of these infectious agents in the abortion cases of domestic ruminants and in wild ruminants in Hungary. During the research we examined samples from throughout the country originating from cattle, sheep, and goats and we collected placentas of red deer, fallow deer and roe deer during three hunting seasons from the south-western part of Hungary. From the cotyledons 3x3 cm large pieces were cut out and fixed in 8% formalin for histology and immunohistochemistry method (IHC). Pieces of the same size from the cotyledons were sliced up then homogenized and issued for manual DNA extraction for the real-time polymerase chain reaction assays (PCR). The samples were examined with C. burnetii- and Chlamydiales order specific real-time PCR and with C. burnetii- and Chlamydiaceae family specific IHC. According to the real-time PCR results, out of the 111 abortion samples from domestic ruminants 21 animals were infected with C. burnetii (cattle, n=19; sheep, n=2), members of the Chlamydiales order were detected in 20 cases (cattle, n=11; sheep, n=8; goat, n=1) and both bacteria occurred in 12 samples (cattle, n=3; sheep, n=8; goat, n=1). However, only 20 of the positive cases were confirmed by IHC (C. burnetii, n=2, in sheep; Chlamydiaceae, n=17, in sheep /n=15/ and goat /n=2/; and both pathogens in one sheep). Out of the 91 abortion samples from wild ruminants two animals were positive for C. burnetii with real-time PCR, but none of them was confirmed by IHC. Members of the Chlamydiales order were detected in four placenta samples, but according to the DNA-sequencing none of them belonged to the Chlamydiaceae family.

In conclusion, the causative agent of Q fever, C. burnetii is widespread in Hungary and it can be designated as the primary cause of abortions in several cases. Although we examined relatively few samples originating from sheep, we observed high infection rates with C. burnetii and Chlamydia abortus in the animals, which may lead to public health issues. The ocurrence of members of the Chlamydiales order other than the Chlamydiaceae family is sporadic in both domestic and wild ruminants in Hungary.