Disease spread challenge

A bluetongue disease outbreak in Northern Ireland is challenging assumptions about how the disease is spread.

The outbreak on a farm in County Antrim was in dairy heifers imported from the Netherlands. All the animals involved were culled after it emerged that calves born after arrival were carrying the virus. 

In total 29 animals have been culled without compensation and investigations are continuing into how the disease emerged in calves after pre-movement and post-arrival tests.

Initial tests on the animals suggested they had antibodies to the disease, meaning they had been exposed but recovered. 

In subsequent tests it emerged that at least two were carrying the virus, including one which tested clear pre-movement and after arrival on the farm.

Vets monitoring the farm then found that calves born on the farm had the virus. This could not have come from midges, since there has been no activity and the disease is not circulating.

Tests are now being carried out on the foetuses of culled animals to check for cow to calf transmission across the placenta. 

The farm involved is restricted and the Department of Agriculture in Belfast has stressed that the virus is not circulating, meaning Northern Ireland is still officially bluetongue disease-free.