Bovine Viral Diarrhea/Mucosal Disease is an infectious disease of cattle caused by a virus. In humans, the virus does not cause disease.

The disease is spread worldwide

Cattle, sheep, goats and wild ruminants

Transmission mainly occurs via persistently (permanently) infected animals (PI animals). These animals are already infected in the womb and excrete viruses throughout their lives via all bodily excretions and secretions.

The majority of infections with BVD viruses are asymptomatic. Diarrhoea, fever, respiratory diseases, mucosal erosions, reluctance to eat, reduced milk yield and fertility problems are possible. Pregnant animals can reject, give birth to malformed or weak calves. A particular variant of the disease is mucosal disease, which can be fatal.

There is no therapy against the BVD virus

Bovine viral diarrhoea is a notifiable animal disease. Vaccination against BVD is prohibited in Austria.

Since 17 February 2022, Austria has held ‘disease-free’ status with regard to BVD across its entire territory. Risk-based monitoring of cattle holdings, involving milk and blood samples, is carried out annually.

At the end of 2025, as part of random, risk-based checks on intra-Community animal movements, three cattle that had been brought into Austria from another EU Member State without the required certification tested positive for the BVD virus. Given the negative test results in the country of origin, it was assumed that the infection had occurred only shortly before entry. The spread of the virus within Austria was subsequently ruled out.

Bovine viral diarrhoea/mucosal disease is one of the most economically significant infectious diseases of cattle worldwide. Many countries have opted for active control and surveillance programmes for BVD/MD. The disease is caused by a pestivirus, family Flaviviridae, and is spread worldwide. Host animals are cattle, sheep, goats and wild ruminants.

BVD is mainly transmitted via persistently (permanently) infected animals (PI animals). They are the most important source of virus spread. The development of a PI animal occurs through infection of the unborn calf via the dam between the 40th and 120th day of pregnancy. At this time, the foetus's immune system is not yet fully developed, an immune tolerance to the virus develops, the animals remain infected throughout their lives and excrete the virus. Excretion takes place via all bodily excretions and secretions.

The majority of infections with BVD viruses (BVDV) are asymptomatic. Diarrhoea, fever, respiratory diseases, mucosal erosions, reluctance to eat, reduced milk yield and fertility problems are possible. Pregnant animals can reject, give birth to malformed or weak calves.

Mucosal disease (MD) occurs as a special disease variant. It occurs when a PI animal is also infected with another virus strain. MD is characterised by a severe course of the disease and is fatal. Symptoms of MD are bloody diarrhoea, high fever, mucosal erosions and ulcerations (on the muzzle, nose and interdigital cleft).

To control BVD, virus shedders (PI animals) in the herd are removed to protect the herd from new infections.

The diagnosis of bovine viral diarrhoea is possible both directly (pathogen detection) and indirectly (antibody detection).

Sample material for pathogen detection using PCR or ELISA:

• Blood (serum/plasma)
• Tissue (ear puncture)
• (altered) organs

Sample material for antibody detection using ELISA:

• Blood (serum/plasma)
• Milk (individual and tank milk)

One of the most important goals in BVD diagnostics is the early detection of a PI animal. In serological testing using maternal antibodies (antibodies that are passed on from the mother to young animals via colostrum), BVD viruses can be masked in the blood, making early detection impossible. This so-called "diagnostic gap" does not play a role in the examination of tissue samples and the detection and eradication of PI animals is already possible in the first week of life. Equally problematic is the delayed increase in antibodies after a BVD infection. BVD antibodies are only detectable from around the 7th day after infection. This time delay is even greater when analysing tank milk.

There is no diagnostic gap for PCR diagnostics from a blood sample or when analysing an ear puncture using PCR.