Preliminary Isolation And Studies On PCR Diagnosis Of Sheep Pulmonary Adenomatosis Virus

Sheep pulmonary adenomatosis (synonyms, Jaagsiekte, ovine pulmonary carcinoma), a contagious lung cancer of sheep, was caused by an exogenous type D retrovirus, Jaagsiekte sheep retrovirus (JSRV). In this experiment, three dead sheep from SPA were been as materials to make histopathological and ultrastructural observation.The results showed the primary lesion was the resultant transformation of type II epithelial alveolar cells. Tumors were composed mostly of single layers of cuboidal epithelial cells arranged in an acinar pattern, but all rumors had areas where the tumor cells piled up, forming papillary projections into the alveolar spaces. A striking and unique feature of SPA was the accumulation of fluid within the respiratory tract. According to the histopathological observation, diagnosed the case as sheep pulmonary adenomatosis.In this experiment, the lung cells of embryo sheep were cultured and the cells were infected with JSRV. The infected cells were passaged so that the virus could be isolated. CPE were observed from passage 2 to passage 9 postinfection. The cultured virus supernatants were harvested when CPE were observed in 3/4 infected cells. The virions were found by electron-microscope observation. Studies on JSRV had been hampered by the lack of an infectious molecular JSRV clone and the lack of an in vitro infection system. An in vitro infection system in this experiment was studied.In this experiment, the cultured virus was detected by PCR amplification. Moreover, 3 natural sheep cases, 16 sheep cases and 16 goat cases at random were diagnosed. The results showed 3 natural sheep cases were SPA, 2 of 16 sheep were positive and others were negative, 16 goats were negative. The herds were diagnosed whether they were sheep pulmonary adenomatosis by PCR in order to build up a specific method of diagnosing SPA in this experiment.