Bovine tuberculosis (TB) is a contagious and communicable disease caused by bacteria. It affects cattle, bison, deer, elk, goats, and other species, including humans.
Bovine TB is an old world disease that was imported into North America in domestic cattle during the early stages of European settlement. Bovine TB was common in livestock in Canada, including the Riding Mountain area, but due to management efforts the occurrence in cattle has been significantly reduced. Historically, bovine TB has been a rare disease in wild cervids (elk and deer).
Since 1991 in Manitoba 45 elk and 11 white-tailed deer have tested positive for bovine tuberculosis in the Riding Mountain area. In addition there have been 7 positive cattle herds and one exposed herd. Manitoba Conservation in collaboration with its partners will again be testing hunter harvested elk and deer in the Riding Mountain area for this disease.
At some time in the past domestic cattle with the disease infected elk in the Riding Mountain region. Since the first elk were infected in the region, the disease has likely been transmitted back and forth between elk and domestic stock, because both species are capable of transmitting the disease to the other.
In December 1998, an elk that died naturally in Riding Mountain National Park (RMNP) tested positive for bovine TB. As a result of this occurrence, Manitoba Conservation, Manitoba Agriculture and Food, Parks Canada, and the Canadian Food Inspection Agency, and have undertaken a bovine TB surveillance program in the western part of the province. Hunters in GHAs 13A, 18, 18A, 18B, 18C, 23 and 23A have provided big game samples for to Manitoba Conservation for testing. Over 10,000 samples have been collected and analyzed. In addition, the Canadian Food Inspection Agency tests cattle herds in the Riding Mountain Region where Bovine TB infections is suspected.
Bovine TB is different from the human form of the disease. It is highly unlikely that a hunter would contract bovine TB when field dressing or eating the meat of an infected animal. Hunters can reduce any risks during field dressing game by avoiding exposure to open wounds, wearing rubber gloves and washing promptly afterwards. Cooking meat well, until the juices run clear, readily kills the organism. Also, when field dressing an elk or deer, hunters should look for tan or yellow pea-sized lumps in the wall of the rib cage or lungs. If these lumps are present, the hunter should immediately stop handling the carcass, attach the game tag, and contact the nearest Manitoba Conservation or Riding Mountain National Park office. Hunters who surrender a diseased carcass under this disease monitoring program will be eligible for a replacement license. Note that lumps the size of large coins (toonies) are generally tapeworm cysts and are not a concern.
Cattle and elk can contract bovine TB when infected bodily material (saliva, urine, manure) is transferred directly from one animal to another, or indirectly when an animal feeds on infected feed. Bovine TB normally does not sustain itself in wild elk populations with density levels that occur in the Riding Mountain region. The most likely explanation for the perpetuation of bovine TB in elk is that animals have transmitted the disease where they congregate at hay storage, supplemental feeding, intercept feeding, and illegal deer and elk baiting sites. These concentrations have been occurring around the Riding Mountain to an ever-increasing degree over the past three decades mainly as a result of increased hay production and the use of round bales. Round bales can be left in the field for extended periods of time with limited depletion of hay quality. These bales can become infected when fed on by animals with bovine TB. When other elk or cattle later feed on the infected hay, disease transmission can occur.
There are no effective vaccines or medications for disease prevention and treatment of bovine TB in wild elk and deer. A multi-agency Task Group for Bovine Tuberculosis was established in 2000 to coordinate a program to eliminate the disease. The Task Group has representatives from Manitoba Conservation, Manitoba Agriculture and Food, the Canadian Food Inspection Agency and Parks Canada; The Manitoba Cattle Producer’s Association and the Manitoba Wildlife Federation also provide input as major stakeholders. A comprehensive Bovine TB Management Program is in effect, which is managed and funded by the four government agencies.
Hunters will only receive information about the sample they submit if there is an indication that the animal was infected with bovine TB. A preliminary notice of a possible infection usually will be received within two weeks and a notice of confirmed infection will be received after four to five months (a bovine TB culture takes up to four months to develop).For further information, please call Manitoba Conservation and Water Stewardship in Dauphin, (204)622-2474