engleski

Chlamydophila psittaci in pigeon and pet birds in Croatia

The infection caused by Chlamydophila psittaci (C. psittaci) has to be mandatory reported in Croatia, and previous investigations revealed frequent presence of C. psittaci in birds, especially in city pigeons, but also in turkeys and laying hens. Because of the zoonotic potential of C. psittaci, it is important to make a rapid, definitive diagnosis in birds. Most commercially available tests are based on monoclonal antibodies against genus-specific epitope of chlamydial LPS, like ELISA test, but from the previous investigations it is well known that sometimes non-specific positive results can appears. Altogether 411 samples (feces, cloacal or so called triple swabs-conjunctival, pharyngeal and cloacal swab together) were taken from pigeons, parrots, canaries and finches. The samples were taken in pet shops, at the breeders, in the Clinic for birds of the Faculty of Veterinary Medicine University of Zagreb, and in the ZOO. The birds were examined for their health status or as sick ones in the Clinic for Birds. From that, 169 samples were from racing pigeons, 177 from parrots, 58 from canaries and 7 from finches. For the detection of specific C. psittaci antigen commercial ELISA kit was used- IDEIATM PCE Chlamydia kit (DAKO Cytomation Ltd., UK). The samples that were by ELISA test described as suspicious positive were also examined by PCR as described by Hewinson et al. (1997). Total DNA was extracted by commercial DNeasy® Blood & Tissue Kit (Qiagen, USA). The expected PCR amplicon were at 264 bp corresponding to the ompA gene. All of the 411 samples were examined by ELISA test to reveal the presence of specific antigen of C. psittaci. Out of them, 70 were positive (17.03%). Regarding the sampling place, majority of the positive samples were found at the breeders (18.91%), in the pet stores (17.39%), while there was only few positive samples from the Clinic and ZOO (both 8.33%). According to the bird species, the most positive were pigeons (23.08%), followed by canaries (15.52%) and parrots (12.43%). All the samples from finches were negative. Extremely high titre of positive samples obtained by ELISA test were considered as suspicious due to the fact that LPS antigens of some other bacteria can cross-react with monoclonal antibodies specific for chlamydial LPS. For that reasons, all suspicious samples (26) were also examined by PCR. Out of 18 suspicious samples from the pigeons only one was described as PCR positive. On the other hand, 8 suspiciously high positive samples from the parrots and canaries were PCR positive in 75% and 100%, respectively. Finding of 17.03% positive samples can represent a potential threat for human health, but has also confirmed the need for monitoring of the prevalence of Chlamydia in different bird species, both at the breeders and in pet stores. The PCR has been shown as the method of choice when is necessary to clarify nonspecific or suspicious results, obtain by other methods.

Chlamydophila psittaci; pet birds; epidemiology; ELISA; PCR

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