Bovine TB Strain Confirmed in Michigan Hunter; Hunters Reminded to Wear Gloves When Cleaning Game

State and local health officials have confirmed a strain of bovine tuberculosis (TB) in a hunter who was injured while field dressing a white-tailed deer.

The deer, taken from Alcona County in October 2004, had physical signs of bovine TB in its chest, said Dianna Schafer, public health officer for District Health Department No. 2. While field dressing the deer, the hunter cut himself on the hand. Upon seeking medical attention, physicians ran tests for bovine TB, which were confirmed last week at the Michigan Department of Community Health (MDCH)s laboratory in Lansing.

This appearance of bovine TB in a human underscores the human health risk of the disease in free-ranging deer, said Janet Olszewski, MDCH director. People should not consume wild animals that appear or are confirmed to be sick, regardless of the circumstance.

Dr. Dean Sienko, acting state chief medical executive, said the method of infection was rare, and health officials in Alcona County moved very swiftly to diagnose the disease. The hunter, now on a typical course of antibiotics for treatment of TB, is expected to make a full recovery. The hunter is not infectious, he said.

This unique occurrence of bovine TB strengthens the message the Michigan Department of Natural Resources (DNR) has consistently articulated hunters should take precautions and wear gloves when field dressing deer, washing their hands afterwards, said DNR director Rebecca Humphries.

Since 1996, information to help hunters identify TB in deer and protect themselves from infection has been published yearly in the DNR Hunting and Trapping Guide. Hunters who harvest deer that have suspicious physical signs continue to be advised to bring the carcass to the nearest DNR field office for examination.

Bovine TB is a serious zoonotic bacterial disease that affects primarily the lungs and sometimes the digestive tract of a variety of animals, including cattle, goats, deer, and elk. It can be passed to humans, but is treatable in humans with a 9-to-12-month regimen of antibiotics.

Bovine TB infection is generally transmitted to humans through consuming unpasteurized milk or milk products obtained from infected cattle. People also can be infected through the air when in close contact with live animals that have lung infections. This particular hunters infection resulted from direct contamination of a wound, Sienko said.

Sienko also urged individuals that think they may have been exposed to bovine TB, either through harvesting a confirmed TB-infected deer or through the confirmation of a TB-positive livestock operation, to request a tuberculosis skin test (TST) from their primary health-care provider.

Some people develop active TB soon after becoming infected, before their immune system can fight the TB bacteria, Sienko said. Other people may get sick later, when their immune system becomes weak for some other reason. Latent TB infection is a condition in which TB bacteria are alive but inactive in the body.

People with latent TB infection have no symptoms, do not feel sick and cannot spread TB to others, but they usually have a positive skin test reaction and may develop TB disease or infectious TB later in life if they do not receive treatment. However, more than 90 percent of people with latent TB never develop active TB.

Originally introduced by infected cattle, bovine TB is now found in a small percentage of northern lower Michigan white-tailed deer and has spilled back into cattle herds in the area. Both the Michigan Department of Agriculture (MDA) and the DNR inform citizens of the importance of a skin test when they have been exposed to infected animals.

The Michigan Bovine TB Eradication Project is a multi-agency team of experts from MDA, MDCH, DNR, Michigan State University, and the United States Department of Agriculture that work cooperatively to establish policies and enforce regulations to eradicate the disease. For additional information on bovine tuberculosis in Michigan, visit www.michigan.gov/emergingdiseases.