Seroprevalence and Risk Factors for Bovine Herpesvirus 1 Infection Among Dairy Cattle in Western Thailand

Infectious bovine rhinotracheitis (IBR), caused by bovine alphaherpesvirus 1 (BoHV-1), is a highly contagious disease that causes substantial economic losses in the cattle industry. BoHV-1 is endemic worldwide and affects both beef and dairy cattle populations. However, data on the seroprevalence of BoHV-1 infection in Thailand remain limited. This cross-sectional study investigated BoHV-1 seroprevalence and potential risk factors among 290 randomly selected dairy cattle from 22 farms in western Thailand. An indirect enzyme-linked immunosorbent assay (ELISA) was used to detect an-tibodies against BoHV-1. In addition, farmer interviews were conducted to collect information on potential risk factors. Univariate binary logistic regression analyses were performed to assess asso-ciations between the investigated variables and BoHV-1 seropositivity. The overall apparent ani-mal-level seroprevalence was 18.28% (95% confidence interval [CI]: 13.83–22.72%), while the esti-mated true seroprevalence was 20.07%. At the farm level, 15 of the 22 farms were seropositive, cor-responding to a farm-level seroprevalence of 68.18% (95% CI: 48.77–87.59%). At the individual an-imal level, a history of respiratory problems was identified as potential risk factor associated with BoHV-1 seropositivity. At the farm level, farm certification for Good Agricultural Practices status tended to play as preventive risk factor. These findings provide preliminary epidemiological data on BoHV-1 seroprevalence in dairy cattle in western Thailand and highlight the importance of further investigation into factors associated with BoHV-1 exposure at both the animal and farm levels.