First molecular detection of bovine gammaherpesvirus type 4 in dairy cows of Iran and its possible role in endometritis

A remarkable percentage of cows in industrialized dairy farms can be affected by uterine diseases including endometritis. Different viral and bacterial agents are causing endometritis in dairy cows including Trueperella pyogenes, and bovine alphaherpesvirus 1. Also, bovine gammaherpesvirus type 4 (BoGHV-4) is responsible for different reproductive disorders. The present study aimed to investigate the role of BoGHV-4 in histopathological and cytological changes of post-partum uterine diseases and its relation to bacterial co-infection. Forty-seven uteri were collected from Holstein dairy cows at least 35 days post-partum. Bacterial culture, cytological, and histopathological studies were conducted on the endometrial samples. The PCR reaction was conducted for the sequencing of the gB gene. PCR examination indicated that from 47 uteri obtained from a slaughterhouse, 13 uteri (27.7%) were positive for BoGHV-4. Statistical analysis revealed a significant relationship between virus presence, and histopathologic and cytologic endometritis (P < 0.05). Also, Escherichia coli and Fusobacterium necrophorum presence was significantly related to BoGHV-4 infection. Vast varieties of other bacterial species were isolated from different samples but the relation between these bacteria and BoGHV-4 was not significant (P > 0.05). Altogether, it can be concluded that BoGHV-4 can play some roles in establishing endometrial inflammation increasing leukocyte infiltration in endometrium, and enhancing bacterial infection in the uterus of dairy cows. This is the first study, which detected the BoGHV-4 in Iranian cows using molecular methods.