What to expect if your farm is part of the investigation for bovine tuberculosis
About bovine tuberculosis
Bovine tuberculosis (TB) is a chronic contagious bacterial disease of livestock, and occasionally other species of mammals, resulting from infection with Mycobacterium bovis (M. bovis).
The bacteria associated with the disease may lie dormant in an infected animal for years without causing clinical signs or progressive disease, only to reactivate during periods of stress or in old age. When disease does become progressive, this generally results in enlarged lesions which may be found in a variety of tissues including lymph nodes of the head and thorax, lung, spleen, and liver. When progressive disease does occur, clinical signs include weakness, loss of appetite, weight-loss and fluctuating fever. When the lungs are extensively diseased, there can be an intermittent, hacking cough.
Infected animals with progressive disease shed the bacteria in respiratory secretions and aerosols, feces, milk, and sometimes in urine, vaginal secretions, or semen. As a result, disease may be spread in a variety of ways, most commonly through the inhalation of micro-droplets in aerosols from already infected animals and from the ingestion of contaminated food and water.
Detection of bovine tuberculosis in Canada
After nearly a century of effort, financial investment, and close collaboration on the part of various federal, provincial and industry stakeholders, Canada has made great strides towards eradication. Ongoing surveillance to detect any new infections of bovine TB in livestock maintains Canada's hard-won health status for TB and plays a role in maintaining and opening access to markets for Canadian livestock and livestock products. As a "
federally reportable disease" in Canada, producers and veterinarians must report any suspect cases of bovine TB to the Canadian Food Inspection Agency (CFIA). The CFIA also conducts ongoing surveillance in federal abattoirs where 95% of all commercial animals are slaughtered and inspected. Any tuberculosis-like lesions in the lymph nodes and lungs are submitted for testing to rule out bovine TB. Any suspect or positive cases are traced from slaughter back to the herd of origin in order to investigate further or, where disease has been confirmed, conduct disease eradication activities. Finally, on-farm testing of livestock is conducted in specific higher risk situations including in areas where there is infected wildlife may spread disease to livestock. Refer to Fact Sheet – Wild Animals.
Suspicion of bovine tuberculosis
When there is reason to suspect that a herd may be infected with bovine TB the CFIA takes actions to investigate and, when present, respond to eradicate the disease. While all investigation and response situations are different, the steps involved in a bovine TB investigation/response normally include the following:
- destruction and disposal
- cleaning and disinfection
It is important to note that the occurrence of bovine TB in Canada today is rare and hence the majority of investigations ultimately serve to rule out the presence of disease. This activity remains important, however, to ensure prompt detection and eradication of the disease to prevent its establishment and spread.
When there is reason to suspect that a herd may be infected with bovine TB, a CFIA official (usually the district veterinarian) will visit the premises to meet with you. At this stage, a precautionary movement restriction may be placed on your premises to control the potential spread of disease from herd to herd if infection is present. You will be provided documentation outlining the rules of the quarantine, discuss your responsibilities, and answer any questions you may have.
Under the quarantine, no livestock, livestock products or by-products (such as manure) will be allowed to enter of leave the property without CFIA permission.
While your property is under quarantine, your responsibilities may include:
- maintaining fences and gates around the farm to control the movement of animals and animal products
- informing all persons entering the farm of the quarantine
- reporting all sick and dying animals, and any that escape the farm
- cleaning and decontaminating farm tools and equipment that may have been exposed to infected animals
If bovine TB is ruled out by subsequent tests and investigation, the precautionary quarantine is lifted, and no further actions are taken.
The CFIA veterinarian will start an investigation by asking a series of questions about the health of your livestock and the management practices you use. They will provide advice and complete a disease report on the incident in your herd. To help CFIA staff in their investigation, you may be asked to provide the following information on your farming enterprise and how it is managed:
- a detailed description of farm management practices including a biosecurity plan
- herd inventory records (for example, birth, purchase, sale, mortality, production, feed and water intake)
- veterinary records and laboratory reports
- records of animal movement on and off the premises, to and from shows, fairs, etc.
- a site map of the farm
- contact information for the farm veterinarian
Because of the challenge of detecting bovine TB in live animals, the investigation may include different types of on-farm testing. The relationship of your herd to an infected herd will determine which tests will be used.
All cattle will have a tuberculin skin test with blood tests as required by your herd's status and the results from the tuberculin test.
Tuberculin skin tests are currently used throughout the world to test for bovine TB and are the internationally accepted standard for detection of infection in bovines and cervids.
The CFIA will provide you with additional information about which tests will be used for your herd before testing is scheduled.
If the on-farm testing does not rule out the possibility of bovine TB, any animals that have reacted to the tests will be ordered destroyed (with compensation paid) for confirmatory testing. The animal is subject to a detailed post-mortem examination, followed by the laboratory examination and testing of any abnormalities that may be observed as well as a selection of normal tissues.
Your cooperation and that of any other parties involved is critical to the success of the investigation.
Under the Health of Animals Act, the CFIA may compensate owners for animals and things ordered destroyed during disease investigation or response situations. Compensation awards are based on market value, up to the maximum amounts established by the regulations, less any carcass value paid by an abattoir.
For more details on the compensation process, please see Animal Health Compensation: What to expect when an animal is ordered destroyed.
As directed by the Privacy Act and other federal statues, the CFIA is required to protect private information collected. Any information provided by you during a disease investigation or response situation is treated as confidential, unless otherwise indicated.
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