عنوان مقاله [English]
This research was carried out on 4 seronegative native sheep to pestiviruses around the age of 3.5- 5years. 3 of animals were injected via. I.M with amount of 2 x TCID5O NADL strain of BVD virus, one sheep was kept as control. In all three infected sheep the leukopenia started the day after injection and reached a peak on 5-8 days post infection. The lymphocytes were the mostly affected cells. Also an elavated temperture (41.5° C) was seen in infected sheep and lasted for 3-4 days. There was no obvious effects of the virus on respiratory and digestive tracts. The control sheep didn’t show any abnormalitis in WBC count and clinical examination. 44 days post infection all 3 sheep under experiment had developed antibodies against pestivirus (SN and ELISA test).