What is bovine TB?

Bovine Tuberculosis (TB) is a chronic, highly infectious disease of cattle (and other mammals) caused by Mycobacterium bovis bacteria. It is related to Myobacterium tuberculosis bacteria that cause TB in humans.

Symptoms usually take months or years to appear and can also lie dormant in the host, without causing the disease. Typical clinical signs include weakness, loss of appetite, weight loss, fever, coughing and eventual death. The usual route of infection is by inhaling infected droplets which are expelled from the lungs by coughing.

Calves and humans can also become infected by ingesting Mycobacterium bovis in raw milk from an infected cow. However, these bacteria are destroyed by pasteurisation, which limits the spread to humans. Precautionary measures such as boundary fencing and hygiene can be implemented to reduce the spread of disease among animals. Wildlife, especially badgers, infected with Mycobacterium bovis may be a significant factor in the persistence of bovine tuberculosis in certain areas.

The ideal long term solution to bovine TB is eradication and the Department of Agriculture Food and the Marine have an eradication programme in place which involves testing and culling of infected animals. The average herd incidence in Ireland was 3.47 % in 2017 and is showing a gradual decline in the past ten years.