The prevention and control of IBR is based either on preventing the virus from entering the herd or on vaccination. Many European countries have eradicated or are in the process of eradicating IBR. There is no official eradication programme in the UK. It is expected that, in the future, restrictions on the trade of live cattle from the UK into IBR-free countries will be introduced. A number of IBR-free accredited herds, selling breeding animals, do exist in the UK.
Preventing the disease from entering the herd
Animals infected with BHV-1 remain infected and shed the virus throughout their lives, particularly at times of stress, such as other disease, calving, transport etc. Entry of such a BHV-1 carrier is usually the source of infection in a herd that has not been exposed to BHV-1 before. Whilst vaccination is an effective way of controlling the disease, it does not stop infected animals from shedding the virus and is not a quarantine against introduction of the disease into a herd.
Therefore attempts to prevent the disease from entering the herd should be based on good herd health security (see Good Practice).
Screening, eradication and accreditation
It has also been shown that in closed herds the virus circulates from infected to non-infected animals, and disease eradication has been successfully carried out in beef herds by segregating the seropositive and sero-negative animals (Corkish, 1988; Ackerman et al., 1990).
To be able to sell IBR-free accredited breeding stock, a farm can acquire accredited status via the Premium Cattle Health Scheme or Herdcare. At less cost and with less stringent biosecurity regulations, a farm can also be a part of a screening and eradication programme for IBR with the same organisations.
Vaccination
At the moment, there are four live, attenuated or inactivated IBR vaccines available in the UK. Most of them are administered intranasally and are often used in the face of an outbreak when they might reduce the number of new cases.
One initial dose with annual boosters is adequate for cattle over three months of age. If younger calves are vaccinated, for example before transport to another farm, two doses, at an eight-week interval, should be given. The efficacy of vaccination of calves before movement to other farms has, however, been questioned (Martin et al., 1984).
In the absence of a marker vaccine (allowing testing to differentiate between the immune reaction elicited by the vaccine and exposure to the virus), vaccination cannot be used in combination with testing and eradication of IBR from a herd.