Rare M. bovis Infection Found in Michigan Deer Hunter
By Ethan Covey
A new report highlights the risk posed to deer hunters, especially those who live or hunt in Michigan, of pulmonary tuberculosis caused by Mycobacterium bovis bacteria.
Although the risk for exposure is rare, epidemiologists have noted that deer populations in the Lower Peninsula of Michigan have far higher rates of M. bovis infection than other areas (MMWR Morb Mortal Wkly Rep 2019;68[37]:807-808).
“The M. bovis bacteria can cause a latent infection that sometimes progresses to active disease, similar to other forms of tuberculosis,” said Laura E. Power, MD, a clinical assistant professor of epidemiology at the University of Michigan School of Public Health, Ann Arbor.
In May 2017, the Michigan Department of Health and Human Services was notified of a case of pulmonary tuberculosis, cased by M. bovis, in a 77-year-old man. The individual reported frequent deer hunting and field dressing of deer carcasses.
The man lived in the northeastern Lower Peninsula of Michigan, where rates of M. bovis have been estimated to affect 1.4% of deer. This rate of incidence is far higher than the estimated 0.05% of deer infected in other parts of the state. Two other cases of hunting-related human infections with M. bovis were reported in Michigan in 2002 and 2004.
“The study alerts health care providers that there is potential for hunters to acquire M. bovis infection while field dressing deer,” Dr. Power said. “The risk is generally low and more relevant in the northeastern part of the Lower Peninsula of Michigan.”
Dr. Power noted that hunters can minimize risk by wearing protective gloves when field dressing deer. Also, if evidence of M. bovis disease is discovered in a carcass—such as tan or yellow pea-sized lumps, often in the wall of the rib cage or in the lungs—individuals should immediately stop handling the carcass and contact the local wildlife agency.
“The Michigan Department of Natural Resources (DNR) has an excellent surveillance system for this disease,” Dr. Power added. “Hunters can submit a deer head to DNR check stations in Michigan, and the DNR will assess the deer head and notify the hunter if any evidence of M. bovis or another chronic wasting disease is found.”
Additionally, Dr. Power noted that the American Veterinary Medical Association provides a list of precautions that deer hunters can take to protect themselves from M. bovis and other infections, at this link: Disease Precautions for Hunters
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