EN
The possibility of jaagsiekte sheep retrovirus (JSRV) genome detection in peripheral blood leukocytes and respiratory tract fluid of ovine pulmonary adenocarcinoma (OPA) affected sheep was tested. Five of six lambs used in the experiment were infected with JSRV by intratracheal inoculation. The blood samples were taken from all the lambs at 10-d intervals for 3 months and the white blood cells were subjected to DNA isolation followed by PCR amplification for the detection of proviral DNA that gave negative results for all the samples. The respiratory tract fluid was collected from the nostrils of lamb No. 6, which developed clinical sign of OPA 2 months after the inoculation. The fluid was examined using PCR and reverse transcriptase PCR (RT-PCR) for the presence of proviral DNA or viral RNA. The presence of OPA in the lamb was subsequently confirmed by histopathological examination and the detection of proviral DNA in the lung tissue. Results of the standard PCR amplification performed on the DNA isolated from the nasal discharge from lamb No. 6 was negative, while the RT-PCR gave positive results confirming the presence of virions in the lung fluid. Results of the study show the RT-PCR technique may be a useful tool in ante-mortem diagnosis of OPA, especially in distinguishing it from other respiratory diseases.