Questions and Answers on current status: Bovine Tuberculosis investigation – Alberta and Saskatchewan
These questions and answers should be considered the latest information and reflect the current status of the investigation.
What is the current state of the investigation and what are the next steps?
The Canadian Food Inspection Agency (CFIA) is continuing to make progress in its bovine TB investigation in response to the detection of the disease in an Alberta cow in September 2016.
The CFIA has depopulated the infected herd and the highest risk herds that co-mingled with the infected herd. Six cases of bovine TB were confirmed in the index herd.
The CFIA has also identified animals that left the infected herd in the last five years (trace-out animals) so that the trace-out animals could be destroyed and their herds could be quarantined and tested. The testing for trace-out animals is largely complete with no additional cases to date.
The next phase of the bovine TB investigation will involve trace-in herds. Trace-in herds are herds with animals that were introduced to the infected herd over the past five years The testing of trace-in herds is important because it may allow the CFIA to determine the source of infection and is required to maintain Canada's bovine TB status. However, it is possible that the source will not be identified. Testing of trace-in herds is also important because it provides reassurance to Canada's trading partners.
Can you confirm that the six TB positive cases are related?
Test results confirm that the six cows that tested positive all have the same strain of TB.
Does leaving the trace-in herds which may be the source of the current cases untested until the fall increase the risk of disease spread?
The herd of origin for the one confirmed case that was not born on the infected premise has already been identified and tested with reactor animals scheduled for destruction and testing. The outstanding trace-in herds are considered low risk.
What is the source of these cases of TB? Is it possible it could come from wild elk in the region?
The investigation is ongoing. Genetic analysis has shown that the bovine TB organism from the infected cows is not the same as any strains detected in Canadian domestic livestock or wildlife or humans to date. All six currently confirmed positive cows have the same strain of TB. This strain of TB identified in these confirmed cows is closely related to a strain first found in cattle in Central Mexico in 1997.
Based on this information, it is unlikely that wildlife is the source of this outbreak.The source of an infection can be difficult to identify, especially with cases that occur far from places where bovine TB is known to be present in wild animals.
The priority area for the CFIA investigation is domestic livestock as disease management in wildlife is under provincial jurisdiction. The Agency is working with the provincial governments of Alberta and Saskatchewan to ensure that any risks associated with TB in wildlife in the area of the infected farming operation are included in the investigation. The Agency will work with provincial authorities to determine appropriate surveillance and testing activities of wildlife in the proximity of the infected premises going forward.
Why will the Agency now focus on tracing only one farming operation?
The Agency has completed depopulation of all mature cattle from the 18 farming operations that were declared to be infected, and has conducted screening tests on all these animals. All of the cattle that reacted to the initial screening test received enhanced post-mortem examinations that included more detailed examinations for the presence of lesions related to bovine tuberculosis.
Based on the evidence that we have gathered to date, the Agency has determined that the investigation going forward will be focused on the one infected farming operation. However, this path forward is only possible as long as no new cases of tuberculosis are identified.
We have worked closely with the governments of Alberta and Saskatchewan. We all agree that the evidence supports focusing the investigation on the infected farming operation. Our evidence shows that there is low risk that the disease was further transmitted by the cattle that co-mingled with the infected herd on the community pasture. Additionally, we have also eliminated the risk of further spread of tuberculosis since all mature cattle have been completely depopulated.
Will there be any changes to compensation to producers?
There are no changes to compensation available to producers. The Agency will compensate producers for animals ordered destroyed under the authority Health of Animals Act.
In addition, payments to Alberta producers are being processed through the Canada-Alberta Bovine Tuberculosis Assistance Initiative (CABTAI) to cover the extraordinary costs they are facing as a result of the quarantine measures. Saskatchewan producers can contact the provincial government directly for similar support. This includes feeding and water infrastructure, feed for the animals, transportation, cleaning and disinfection as well as interest costs on loans due to the circumstances.
What farms will have to undergo CFIA-approved cleaning and disinfection?
The premises where the infected herd and those that co-mingled with the infected herd resided will have to undergo CFIA-approved cleaning and disinfection (C&D), which includes a 45-day waiting period of warmer temperatures. Once this is completed and verified by the CFIA, these producers will be allowed to restock. On-farm testing of the restocked animals is required 6 and 18 months after they are introduced to the premises to ensure the effectiveness of the C&D.
In addition, parts of the community pastures where the infected animals had spent time will also require C&D.
Will the premises where the infected herd and those that co-mingled with the infected herd resided require testing after restocking?
Once these premises have been restocked, the Agency will test the new herds after six and 18 months. The post-restocking testing provides an additional level of confidence about the effectiveness of the C&D and any residual risk with the affected premises.
What are the next steps?
The Agency will continue with trace-in and trace-out investigations associated with the one infected farming operation. Tracing activities will not be conducted on the co-mingled herds as long as there are no TB infected animals identified from these herds.
Some premises that have received animals from the infected herd are currently under quarantine. The CFIA conducts screening tests on these animals. Only animals that react to the tests will be humanely slaughtered and an enhanced post-mortem examination will be conducted. Further testing, including culture, is conducted on tissues collected at the post mortem. Herds that have no reactors can be released from quarantine.
While we have focused extensively on the potential for the spread of disease so far, we are now turning our focus to identifying the source of the infection. This is done by identifying the herds of origin for all animals that were introduced into the infected farming operation over the past five years.
What happens to producers that are identified as a result of the ongoing tracing activities for the infected herd?
The CFIA continues to identify farms through tracing activities, such as those that supplied cattle to the infected herd in the past five years.
Producers will be notified as new herds of interest are identified. As calving season has started, testing of these herds will begin in the fall. This will minimize stress on cows that are pregnant or have recently given birth. It will also allow cattle from these low risk herds to proceed to summer pasture. This will cause the least disruption to normal farming operations for these producers.
When will the Agency finish culture tests for producers with live cattle that are still under quarantine?
The Agency will inform the individual producers on the status of the test results required to release the quarantines on their premises.
What cleaning and disinfection will be required for the premises where the infected herd and those that co-mingled with the infected herd resided?
The CFIA district veterinarian will assist producers in developing an effective cleaning and disinfection plan for their site. The premises must be thoroughly cleaned and disinfected, in accordance with international standards. This process includes cleaning and disinfecting all hard surfaces, structures, tools, equipment and vehicles. In addition, some soil in high traffic areas may need to be removed. For outdoor areas, a 45-day waiting period of warm temperatures is required to kill any bacteria remaining in the environment.
What are the specific additional elements examined during the enhanced post-mortem?
The enhanced post-mortem involves the taking of tissue samples for further testing in a CFIA laboratory. Three additional tests designed to detect the tuberculosis bacteria will be conducted on these tissues:
- The tissue samples will be examined under a microscope to try and detect the presence tuberculosis bacteria.
- Samples will also undergo a polymerase chain reaction (PCR) test which searches for DNA from tuberculosis bacteria.
- The final test is the tissue culture test where the laboratory attempts to grow the bacteria. The culture test takes approximately 12 to 14 weeks to complete.
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