بررسی جداسازی و تعیین هویت مولکولی ویروس زبان آبی در کانون های بیماری در استان های مختلف کشور

Bluetongue virus is an economically important infectious, insect transmitted disease of domestic and wild ruminants specially sheep. A number of methods for detection of BTV have been developed over the past years. But among them the molecular technique like PCR introduced as the most sensitive and reliable one. The other valuable application of PCR is about Phylogenetic analysis of different strains of the viruses. By this method it can be determined the Topotype and the origin of the virus. In this study, total number of 1058 blood samples gathered from sheep with bluetongue-like clinical sign. The samples collected from seropositive region in eight provinces, including Fars, Khuzestan, West Az, East Az, Ardabil, Ilam, Kurdistan and Qum .At first the samples were evaluated by competitive ELISA for detecting Ab against VP7 antigen. Then the S7 gene, as a serogroup specific marker detected by one step RT-PCR and nested PCR. Among the blood samples, the number of BTV serogroup positive, PCR positive, and PCR and seropositive determined, 431(43,1%), 83(15,2%) and 79(8%) respectively. For virus isolation 21 PCR positive samples injected to ECE and 25 PCR positive samples inoculated to KC and Vero. But detecting the inoculated samples doesn't show any virus replication. In this research 770bp of S7 gene was sequenced in 16 samples. Genetic relationship between the samples and some BTV strains in both eastern and western Topotype was evaluated. The genotyping analysis of the selected viruses in country showed that they can divide in two distinct clads. First group were more similar to eastern Topotype like, BTV3-China، BTV16-China ، BTV?-India and BTV9-India. The second group was more near to western Topotype, like BTV4-France ،BTV4-Greece ،BTV1-South Africa and BTV10- USA.

Keywords:

ویروس زبان آبی , دام , بیماری زاها , پی.سی.آر , تشخیص (پزشکی)