Systematic Veterinary Virology

BVD

• It is most often a subclinical to mild infection in immunocompetent but naive cattle.
• Occasionally, in naive animals that are infected by virulent strains of BVD, death can occur.
• Biphasic fever (approximately 104°F (40°C)), depression, decreased milk production, and inappetence are typical signs of acute BVD.
• An increased respiratory rate, diarrhoea, and excessive lacrimation may be seen.
• Disease lasts for 1-3 days, and is followed by rapid recovery with production of viral neutralizing antibody. There may be some loss of productivity.
• BVDV can be immunosuppressive and subclinical disease can predispose cattle to other infections such as pneumonia.
• Some noncytopathic BVDV induce clinically severe disease with a high fever (approximately 107°F (41-42°C)), oral ulcerations, eruptive lesions of the coronary band and interdigital cleft, diarrhoea, dehydration, leukopenia, and thrombocytopenia.