The Preliminary Study On Natural Infection With Ovine Lentivirus In Xinjiang Karakul Sheep

7 Xinjiang Karakul ewes from three sheep farms naturally infected with ovine lentivirus (OvLV) were used by pathological studies. There were slight clinical signs relevant to OvLV infection in 5 seropositive ewes. The mastitis in different severity was found in 5 seropositive ewes .The mammary gland was also the most susceptible target organ to OvLV in this study. The lymphoid interstitial pneumonia (LIP), vasculitis, arthritis or synovitis were not seen. According to the description of severity and classification for mastitis by Dr. Deng Pu-hui, the results showed that the severity of mastitis in karakul sheep were less than that in other species caused by OvLV, suggesting that Xinjiang Karakul sheep is a hyposensitivity breed to OvLV.OPPV was proliferated in ovine fetal lung cells culture. Peripheral blood monocytes collected from seropositive sheep were incubated on the ovine fetal lung cells. The cytopathic effects (CPE) and typical multinuclear giant cell formation were observed after the secondary passages. Antigen prepared from infected cells culture supernatant which was concentrated 100 times was positive to OvLV by AGID test. Suggesting that the procedure is a sensitive method for isolating OvLV.In order to amplify gag gene of OvLV, two pairs of primers were designed according to the GenBank sequence. The fragments of gag gene were obtained by polymerase chain reaction (PCR). The gag gene encoded a precursor protein of 444 amino acids was 1332 nucleotides long. The nucleotide sequences of gag gene were compared with other country's strains of OPPV, the homology among them is relative low.