Tuberculosis spreads in Albertian cattle herd

Five more cattle infected with bovine tuberculosis have been found in southeastern Alberta, the Canadian Food Inspection Agency confirmed today.

The five are from the same group as the first cow found with the disease, which was discovered in September after it had been shipped to the United States for slaughter.

Dr. Penny Greenwood, national manager for domestic disease control with the CFIA, said the new positive cases show there has been transmission of TB from animal to animal.

“These positive test results indicate transmission between animals has occurred. The CFIA is currently conducting a risk assessment to determine how these results impact the investigation and whether or not additional herds may be declared infected,” she said.

“All confirmed cases are from the one infected herd, which is located on three separate premises in Alberta. All of the cattle from the herd are in the process of being removed from the premises and humanely destroyed.”

Greenwood said the new cases have no effect on food safety, nor do they represent any impact on cattle or beef trade.

As of today, there are 34 ranches in Alberta and two in Saskatchewan under quarantine, representing an estimated 18,000 animals.

The infected cows are on three different premises because they were commingled in community pastures in the Jenner, Brooks and Suffield regions of Alberta.

The Saskatchewan ranches had cattle adjacent to those in Alberta and were thus included in the quarantine.

Greenwood confirmed previous reports that the strain of TB in the first cow is related to a strain seen in Mexico and it has not been seen before in Alberta. Results of genetic tests on TB strains that affected the other five infected animals have yet to be analyzed.

More than 50 CFIA staff are now involved in the response and testing of the quarantined herds, with priority given to the source herd and trace outs, Greenwood said.

She added that CFIA laboratory resources are sufficient to keep up with the rate of testing and if that becomes an issue, other labs will be used.

Even so, the testing process is expected to take months.

The Canadian Cattlemen’s Association and other groups are working to set up a feedlot where calves from the quarantined cow herds could be fed over the winter. Many of the ranchers involved in the quarantine habitually wean and sell the calf crop each fall and do not have the facilities, feed or in some cases water to overwinter double their usual number of animals.

Greenwood said the province and Agriculture Canada are also looking at options to help producers with access to water and feed for their livestock to get them through the quarantine period.

Some ranchers have questioned whether the large wild elk herd that frequents Canadian Forces Base Suffield, which is in the same area, may have spread the TB.

Greenwood said bovine tuberculosis favours cattle, so elk are “an abnormal host” for the disease. That said, she added a dense elk population could be a low-level reservoir for TB, as has happened at Riding Mountain National Park in Manitoba.

Given that the TB strain so far identified is from Mexico, Greenwood said the CFIA will be considering the ways it entered Canada, be it wildlife, imported cattle or even humans.

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