A survey on the status of the border disease virus infection in sheep with reproductive failure using cell culture and polymerase chain reaction (PCR) methods in Tabriz, Iran

The most important causal agent of border disease (BD), border disease virus (BDV), is a Pestivirus in the family Flaviviridae. In attention to the lack of molecular documented data on the prevalence of BDV in Iran, especially in East Azerbaijan Province, northwest of Iran, this research was designed to determine the prevalence of BDV in suspected ewes that have an antecedent of reproductive failure. Eighty-eight suspected ewes in the breed of Ghezel, Mogan, and mix (Ghezel × Mogan) in five various districts of East Azerbaijan Province (Azershahr, Lyqvan, Osku, Sofian, and Varzqan) were selected. Razi bovine kidney (RBK) cell lines were grown, and the buffy coat layer was separated and inoculated to the monolayer cell culture. All cell cultures were inspected for cytopathic effects after 5–7 days. BDV genomes were being checked using nested reverse transcription polymerase chain reaction method. Ten samples (10/88, 11.36 %) were positive for the genome of BDV. The prevalence of BDV infection was found to vary between different districts. The highest percentage of infected sheep was in animals at the 3–4.5-year-old range (15.38 %). There was no statistically significant difference in the prevalence among different age categories. The highest BDV infection rate was observed in full blood ewes in Mogan and Ghezel. Cytopathic effects of the virus in the culture on RBK cell line were not observed at all. This study proved that the infection of BDV is present in sheep in the East Azerbaijan, northwest of Iran, and cause some reproductive failure in the flocks. The survey is the first molecular evidence of the occurrence of the disease in the country.