Specimen: 10mL serum (>35 days) or ear notch (any age)
Container: Red top or gel tube
Collection protocol: Venepuncture
Special handling/shipping requirements: Ship chilled
General information about the disease:
Bovine viral diarrhoea virus (“pestivirus”) is one of the most significant viral diseases in cattle. Clinically, there are three forms of the disease:
- A persistently infected (PI) form which may/may not have clinical signs
- An acute transient form characterised by fever and diarrhoea and short term immunosuppression. These animals will mount an immune response and clear the virus in 10-14 days.
- Mucosal disease (MD) only occurring in PI animals. PI animals are infected by a noncytopathogenic strain of the virus. A subsequent spontaneous mutation of the virus to a cytopathogenic strain within the PI animal results in MD, characterised by seromucoid nasal secretions, severe erosive lesions in the oral and intestinal mucosa, diarrhoea and death.
General information about when this test is indicated:
BVD antigen ELISA is used to detect BVD virus in individual animals. On the ELISA test, a numerical optical density value, called S-N (sample value minus negative control value) is created. Transiently infected (TI) animals have S-N values of < 1.2 and PIs have S-N values > 2. Reporting shows weak positive (S-N <1.2), positive (S-N 1.2-2), and high positive (S-N >2) results against individual animal results. A weak positive result can be taken to indicate an animal is TI while a high positive result indicates the animal is PI. A positive result could be TI or PI so retesting is indicated in 3-4 weeks. Pooling is not possible with antigen ELISA testing.
Virus screening of all keeper calves is also recommended.
Comparison with other related tests: Used in conjunction with PCR and BVD antibody ELISA testing.
Refer to BVD antibody ELISA for a BVD testing summary.