NewsDesk @bactiman63

The Institute of Public Health is collaborating with the municipal superintendent in the relevant municipality to investigate findings of tuberculosis infection in 6 people in Rogaland county. The persons were sampled (IGRA sample) following the discovery of bovine tuberculosis (Mycobacterium bovis) in a cow that was slaughtered in November 2022.

Image/Robert Herriman

The six who have tested positive are followed up locally in collaboration with the health service according to standard routines for tuberculosis infection. The positive IGRA tests do not say anything about when the infection occurred or whether it is an infection from animals or humans. FHI collaborates with the municipal superintendent to map potential sources of infection, including a possible connection with the slaughter in question.  

A positive IGRA blood test means that you are infected with tuberculosis. Being infected does not mean you are sick. Most people who are infected will never develop the disease. In case of possible disease development, it usually takes a long time from infection to disease (from months to years). In case of confirmed infection, preventive treatment will effectively prevent the development of tuberculosis disease.  

– People who are infected without being sick cannot infect others, says senior doctor Karine Nordstrand. 

The detection of bovine tuberculosis in a cow in Norway in November was the first detection in many years. In connection with infection tracing, people who have had contact with the cow are therefore closely monitored.

Bovine tuberculosis is primarily transmitted between animals, but can also be transmitted to humans. The most common way of infection from animals to humans worldwide is through consumption of unpasteurized milk and milk products. Pasteurization kills the bacteria effectively, and pasteurized milk and milk products are safe to consume. 

– The Institute of Public Health considers that there is no risk of tuberculosis infection to the general population in this case, says senior doctor Karine Nordstand.  

Transmission to humans through contact with cattle occurs relatively rarely and mainly to people who have had close contact over time with an animal with ongoing lung disease.  

About tuberculosis 

Tuberculosis is caused by mycobacterial species belonging to the Mycobacterium tuberculosis complex, and includes M. tuberculosis which is most common in human tuberculosis and M. bovis which causes bovine tuberculosis.  

Tuberculosis infection between people occurs through airborne spread of the tuberculosis bacterium from a person with pulmonary tuberculosis. Tuberculosis in other organs of the body, such as lymph nodes or the skeleton, is not contagious in practice. Close contacts, and especially people in the same household, are most susceptible to infection. Nevertheless, experience shows that only half of the closest contacts become infected. Of those who have been infected, between 5 and 10 per cent will become ill with tuberculosis at some point in their lives.