Bovine TB (bTB) is primarily a respiratory infection. It can progress to clinical disease often characterised by respiratory signs such as a chronic cough. Other clinical signs of TB include loss of appetite, weight loss, weakness, lethargy, fever and grossly enlarged lymph nodes. However clinical signs of bTB in cattle are very rare in NI as infected animals are usually detected in the early stages of infection and long before clinical signs are seen, due to the frequency of testing carried out as part of the NI TB testing programme. Infection can become established in the intestine after ingestion, but this also is rare as it depends on the consumption of large quantities of the organism. The great majority of bTB infections in cattle are sub-clinical, (that is, the symptoms cannot be observed), and can only be detected using diagnostic tests or at post-mortem.
Humans are susceptible to bovine TB and can be infected by drinking raw milk or inhaling infectious aerosols, resulting in symptoms such as a chronic cough, fever and unexplained weight loss. Fortunately, due to the ongoing bTB programme in NI together with milk pasteurisation and meat hygiene inspections, infection with bTB in humans is rare in NI. Those at most risk are people working closely with infected animals or drinking unpasteurised milk.
Public Health Agency advice
NI’s Public Health Agency has given the following advice to those working in the farming community as steps they can take to reduce the risk of exposure to bovine TB:
- wash hands thoroughly several times a day and always before eating, and after finishing work for the day;
- wash skin wounds immediately with soap and running water and cover with a waterproof dressing;
- avoid drinking milk that has not been pasteurised, or eating dairy products made with raw milk;
- if, despite the risks to human health involved, you or someone in your family still wish to consume unpasteurised milk and its products, make sure that the milk comes from an officially TB-free herd;
- do not drink or eat in animal areas.
https://www.publichealth.hscni.net/news/tb-still-increase-northern-ireland