OUTBREAKS OF malignant catarrhal fever (MCF) may be a rare in UK cattle herds, but it is present in UK animals and could be a bigger problem in future years.

Moredun researcher David Haig said the disease was currently a major problem in Indonesia and the USA.

“Once an animal is infected with the disease, it is generally a matter of days before it dies,” he warned.

But not all species infected by the causal agent Sheep Herpes Virus Two are affected by the disease. “Sheep, the carriers of the causal agent, never develop MCF. But deer and pigs are susceptible to infection.”

Additionally, not all cattle infected with the virus go on to develop the disease. “There appears to be some level of resistance associated with the disease. The prominence of disease in North American Bison and Indonesian cattle suggests resistance is linked to breed development and domestication over the centuries.

“European cattle have always co-evolved with domesticated sheep and so have over time developed more resistance to the disease.”

To help prevent future disease spread, Moredun is working on developing a vaccine for the disease, said Dr Haig. “The trial vaccine, which has performed well in trials so far, works by stimulating the antibody response in the nasal cavity.

“Animals are primed with the virus intramuscularly to kick-start the immune response. Then the antibody response in the nasal cavity is stimulated by putting a live vaccine into the nasal cavity. This causes a mucosal layer to form which contains antibodies to the virus, preventing further infection.”

Currently, Dr Haig said, the best way to prevent infection of cattle was to keep them separate from sheep. “It seems lambs of between two and nine months old excrete the virus which is then transmitted by contact or aerosol to susceptible animals nearby.

“Cattle and deer don’t spread the disease, which is probably why the disease is not more prevalent in the UK,” he added.