Department of Community Health Confirms Human Case of Bovine TB
April 10, 2002
Michigan Department of Community Health officials today announced that an elderly individual was diagnosed with bovine Tuberculosis (TB), but died from unrelated causes in February. DNA fingerprinting conducted by the Department of Community Health laboratory has determined the strain of Mycobacterium bovis found in the individual is the same found in cattle and deer in Northern Lower Michigan. The source of infection is under investigation.
"Bovine tuberculosis is a serious bacterial disease that affects primarily the lungs and sometimes the digestive tract of livestock, deer and other wildlife," said Michigan Department of Community Health Director James K. Haveman, Jr. "Due to the fact that it is slow growing, it has taken some time to culture the bacterium and conduct the appropriate DNA testing." The individual lived in a rural area within the Northeast Lower Peninsula. The patient was not coughing and was not likely to transmit disease, Haveman said.
"This patient had underlying health problems and any form of tuberculosis is a risk for persons with history of chronic illness or the elderly," said Haveman. "In this case, tuberculosis was not the cause of death, but was discovered as part of the patient's diagnostic workup."
Physicians and laboratories in Michigan are required by law to report communicable disease cases, including tuberculosis, to local health departments. Rapid and complete reporting assures that timely public health investigations and interventions prevent the spread of disease.
The Michigan Department of Community Health, in conjunction with the state's Bovine TB Eradication Project, continues to emphasize standard bovine TB prevention practices. Because the bacterium is most often found in lung tissues the disease is primarily spread through breathing or coughing but can also be spread by drinking unpasteurized milk or eating improperly cooked meats from infected animals.
Decades ago, unpasteurized milk served as a major source of human infections. Milk in Michigan has been required for years to be pasteurized to assure the safety of Michigan's milk supply. Farm families and others are reminded not to drink unpasteurized milk.
"The possibility of humans contracting bovine TB from animals continues to be extremely remote," said Michigan bovine TB eradication coordinator Bob Bender. "However, hunters or individuals who come into contact with TB-infected animals are encouraged to take extra precautions and contact their physicians concerning the need to have regular TB skin tests."
Extra precautions while handling animals include wearing disposable latex gloves and washing your hands afterward. TB skin tests are offered at local health departments or private physicians' offices. A positive skin test reveals infection, not disease, and does not identify the type or source of the exposure. Bovine TB can be effectively treated in humans, so it is crucial to contact a physician if an individual thinks they have been exposed or have symptoms of tuberculosis including persistent cough, night sweats and unexplained weight loss.
Local health departments in the rural counties where bovine tuberculosis has been confirmed have offered tuberculin skin testing to all persons who feel they may have been exposed to bovine tuberculosis (custom processors, camp personnel, hunters) in their areas free of charge. They are also providing testing to all persons on farms with affected herds.
All meats, including hunter-harvested deer, should be thoroughly cooked to an internal temperature of 165 degrees F for 15 seconds to kill bacteria. If the lungs, ribcage or internal organs from wild deer look abnormal (multiple tan or yellow lumps), the meat should not be eaten and the deer should be taken to a Michigan Department of Natural Resources check station.
Livestock in Michigan destined for consumer use are cooperatively scrutinized by the Michigan Department of Agriculture and the US Department of Agriculture to assure that meat products meet stringent requirements that guard the safety of the food supply.
Consumers also play an important food safety role once meat leaves the retail counter. Prudent handling such as proper hand and utensil washing, proper refrigeration, and using a meat thermometer to cook meat to the proper temperature are all very important.
Since bovine TB was re-discovered in Michigan in the mid-1990's, the state has moved aggressively to develop and implement a comprehensive and stringent TB testing strategy and protocol. Since 1995 more than 760,000 TB tests have been conducted on Michigan cattle, bison and goats and 16,500 privately owned cervids have been tested or are under a herd surveillance plan. In 1997, one privately owned cervid herd was identified with TB and was depopulated. To date, 19 cattle herds have been diagnosed with bovine TB. Two dairy herds are under plans that remove animals responding to TB skin tests, and 17 beef herds have been depopulated.
In addition, over 88,373 TB tests have been conducted on wild white-tailed deer and elk, with 397 deer and two elk confirmed with the disease. Carnivore tests for 2001 revealed two TB positive coyotes, two bobcats and three probe-positive bear, bringing the total number of carnivores that have tested positive for bovine TB to 30.
The Bovine TB Eradication Project is a multi-agency team of experts from the Michigan Departments of Agriculture, Community Health, and Natural Resources, Michigan State University and the U.S. Department of Agriculture. Information on the Michigan Bovine TB Eradication Project can be found at www.bovinetb.com