Diagnosis of Infectious Bovine Rhinotracheitis

Clinical signs of IBR are indicative of BoHV-1 infection but laboratory tests are required for a definitive diagnosis.

Clinical signs

Clinical signs and signalment (young cattle in a feedlot) are indicative of BoHV-1 infection. However many other respiratory diseases may cause the same or similar signs. Often respiratory disease in cattle is caused by multiple concurrent viral and bacterial infections (e.g. Pasteurella multocida, Mannheimia haemolytica etc). Laboratory tests are required for a specific viral diagnosis.

Serology

Virus neutralization

Retrospective diagnosis of BoHV-1 infection can be made by measuring antibody titres in paired sera samples. First sample is collected during the clinical phase and a second sample is collected 4 weeks later.

ELISA

There are two types of BoHV-1 ELISA tests currently available. The use of marker vaccines is important in the differentiation of infected and vaccinated animals.

Post-mortem Examination

• IBR infection is rarely fatal unless complicated by secondary bacterial infection
• Congestion of the tracheal mucosa with petechial haemorrhages
• Inflammatory lesions do not usually extend into airways contained within the lung
• Pustular lesions