First report of histopathological and molecular characterizations of bovine herpesvirus-1 from outbreak at dairy farm in India.

Infectious bovine rhinotracheitis, caused by bovine herpesvirus-1 (BHV-1) is a highly contagious viral disease affecting bovines, and clinically characterized by pyrexia, inappetence, respiratory distress, dyspnoea, conjunctivitis, nasal discharge, and sometimes abortions. In the present study, buffalo dairy farm having high mortality was investigated. The buffaloes were suffering from high rectal temperature, conjunctivitis, severe respiratory distress, and nasal discharge. Tissue samples from upper respiratory tract were collected aseptically following post-mortem examination of died buffaloes. Tracheal tissue samples were then processed for histopathological examination and DNA isolation. The presence of BHV-1 in the tissue samples was confirmed by nested polymerase chain reaction using <i>glycoprotein B</i> gene primers. The present study reported for the first time the clinical signs, post-mortem lesions, histopathological evidence, and detection of DNA of BHV-1 <i>glycoprotein B</i> gene through nested polymerase chain reaction assay during an active outbreak in buffaloes in India. The findings of this study are crucial for improving the diagnosis of BHV-1 and ultimately reducing financial losses within dairy industry.