Pestivirus, also known as bovine viral diarrhoea virus (BVDV), causes abortion, ill thrift in young animals, diarrhoea and increases susceptibility to respiratory disease.
The virus is spread by direct contact from transiently infected or persistently infected (PI) carrier animals, comprising about one per cent of the cattle population, to their herd mates.
Cattle infected by pestivirus can develop ulcerations on their lips and noses which can strongly resemble foot-and-mouth disease (FMD).
Other symptoms of pestivirus include diarrhoea, drooling and weight loss. In severe cases it can lead to death.
First-time exposure to the virus by pregnant cows can result in:
- calf deformity
- poor suckling response
- PI affected calves which appear normal at birth.
There is serological (diagnostic) evidence of this disease on some 90 per cent of Australian cattle properties and it is estimated that as many as 60 per cent of these herds have PI carrier animals present.
Symptoms and diagnosis
Diagnosis of pestivirus will require veterinary assistance. Clinical signs of pestivirus can vary depending on the strain of virus and time of infection.
Clinical signs that would lead a producer to suspect pestivirus include:
- early-term abortion or embryonic loss
- temporary infertility
- increased susceptibility to other diseases
- weak, stunted or deformed calves
- respiratory disease
- ill-thrift and wastage.
Spread between animals
Transmission is by direct contact with an infected animal or its secretions. Conditions that contribute to the spread of pestivirus include:
- Close contact with an infected animal such as in feedlots, yards and dairies, especially if coinciding with stress related events e.g. weaning or the introduction of new animals.
- Recent introduction of a carrier animal(s) into a herd of susceptible pregnant females, especially if introduction of new cattle is into a:
- closed breeding herd or,
- breeding herd in the early stages of pregnancy.
- When a susceptible breeding herd has access to a carrier animal(s) either by contact with other cattle on the property or to neighbours’ cattle across the fence.
If you suspect any form of exotic disease in your animals immediately contact:
- the Emergency Animal Disease Watch Hotline on 1800 675 888
- a Biosecurity SA Animal Health officer
- your vet.