Study On Natural Infection With Ovine Lentivirus (Southern Xinjiang Strain) In Xinjiang Karakul Sheep

1631 sera of Xinjiang karakuer sheep collected from the Southern Xinjiang were tested for antibody to ovine lentivirus(OvLV)(southern Xiniang srtain) by agar gel immunodiffusion(AGID).the results showed that the average positive rate was 1.3% and Xinjiang Kalakuer sheep is a hyposensitivity breed to OvLV in serology. 14 adult Karakuer sheep(female=12,male=2) from sheep farms in southern Xinjiang that were naturally infected with OvLV(southern Xiniang srtain) were studied in this paper. The sera of the 14 selected seropositive sheep were consecutively tested for 18 months(once a month), the results showed that the virus antigen was drift. None of evident clinical signs and OPP-specific gross lesions were seen in all seropositive sheep. Histologically, the lymphocytic interstitial pneumonitis (LIP), vasculitis and arthritis/synovitis were not found in all seropositive sheep, the only typical OPP lesion was of mild lymphocytic mastitis. The result showed that the OvLV strain of Xinjiang Karakul sheep is a hypovirulent strain and Xinjiang Karakul sheep is a hyposensitivity breed to OvLV in pathology. 7 sera from Xinjiang Kalakuer sheep were tested by AGIDT. Ovine lentivirus gag gene that from peripheral blood cells of 5 tested sheep was used as template and amplified by PCR. Then the amplified fragments were cloned into pBS-T vector. The recombination product was transformed into E.coli DH5α.The positive recombinant was screened on Amp/IPTG/X-Gel plates and identified by restriction endonuclease XhoI, clony PCR and then sequencing. The result shows that the PCR are more sensitive than AGIDT and there is some homologue between the gag gene sequence of OvLV (southern Xiniang srtain) and Visna virus.