In 2017, a 77-year-old man in Michigan developed pulmonary tuberculosis (TB). Deer we say how he got it?
A recent publication in the Centers for Disease Control and Prevention (CDC) journal Morbidity and Mortality Weekly Report (MMWR), told this story of TB and not MTB. It was TB because the man had pulmonary TB, a serious lung infection that can potentially cause permanent lung damage. However, it was not MTB, which is short for Mycobacterium tuberculosis. MTB is what usually causes pulmonary TB in humans.
Instead, in this case, the cause was bovis, as in Mycobacterium bovis. Doctors had found M. bovis in the man’s sputum. It’s called “bovis” because cattle is where the microbe is most frequently found. But M. bovis has been appearing in deer as well. As the MMWR publication indicated, in the northeastern Lower Peninsula of Michigan where the man had lived, 1.4% of the deer in 2017 had tested positive for M. bovis. And as I wrote last year for Forbes, there has been increasing concerns that M. bovis could jump from deer to those hunting deer.
Still have no “ideer” how the man had gotten M. bovis? If you are still hunting for an explanation, consider the fact that the man had regularly hunted and field-dressed deer in the northeastern Lower Peninsula region for 20 years. Plus, he didn’t seem to have the risk factors for MTB exposure. For example, he had not traveled to countries where TB is more common or come into contact with any human known to have TB. Oh, and he had not consumed any “raw” milk, which in general is a bad idea unless you like playing diarrhea roulette. Unpasteurized milk can carry M. bovis. Indeed, testing revealed that the microbes found in his sputum had genetic sequences that matched those of M.bovis found in deer.
Here is a CBS KDKA 2 news segment on the case:
The case became a MMWR Case Report since humans getting M. bovis infections from deer still seems to be quite rare. The MMWR publication did mention two other cases of deer hunters getting infected in 2002 and 2004, but so far, this is far from a common occurrence.
Nevertheless, the seriousness of tuberculosis and the continued presence of M. bovis in deer does mean that precautions need to be taken. This includes continued surveillance of and testing deer for M. bovis, encouraging hunters to use personal protective equipment when field-dressing deer (which involves removing their internal organs), and screening hunters for tuberculosis if they come into contact with any deer who have M. bovis.
This is also a reminder that humans are highly interconnected with animal populations. If a disease is spreading in the deer population, humans can’t necessarily just pass the buck so to speak. Diseases in deer could readily affect the health of hunters and others as this case clearly demonstrates.