Bovine TB case of little concern to Ontario producers

Friday, May 16, 2008

by SUSAN MANN

“Right now we haven’t really heightened our alertness based on the fact that there’s a case in Manitoba but it is something we’re keeping at the back of our minds,” says Lianne Appleby, OCA communications manager. “I guess with it being so easily transmissible between cattle is something that we do have to be mindful of.”

The Canadian Food Inspection Agency has done a good job of containing the TB to the one farm and destroying any animals exposed to the infected animal, she adds.

The 240-head herd in Manitoba is located within 10 kilometres of Riding Mountain National Park, in a section of the Riding Mountain Eradication Area that’s considered to be at the highest risk for bovine TB. The area is known to harbour bovine TB in wild elk and deer.

The herd was tested in March as part of the CFIA’s regular enhanced surveillance in the eradication area. The test results for the cow were suspicious and the animal was ordered destroyed. Further testing of tissue samples in CFIA’s Ottawa lab confirmed the cow had bovine TB. No part of the infected cow entered the human or animal food chain.

The CFIA is now investigating the movement of animals both in and out of the Manitoba farm for the past three years, says spokesman Alain Charette. That investigation isn’t done yet. If cattle from this farm moved to any Ontario farms, those herds would be checked.

In addition, any other animals that may have been infected on the Manitoba farm will be ordered destroyed and the farmer will be compensated.

The risk of cattle in Ontario getting bovine TB from wild animals is minimal, says Dr. Warren Skippon, president of the Ontario Association of Bovine Practitioners.

Ontario doesn’t have any bovine TB eradication areas similar to the Riding Mountain one in Manitoba.

Bovine TB is spread through feces, by breathing, coughing, sneezing, and through shared feed and water. Cows can spread it to calves through colostrum or milk. The disease can lie dormant in an animal for many years. Generally farmers don’t know their cows are infected until signs, such as lesions in lymph nodes or internal organs, are found at the packing plant.

Finding bovine TB in Manitoba doesn’t pose a threat to the general public’s health but humans can get TB from animals through prolonged close contact with an infected cow or by drinking its unpasteurized milk. The strain of TB typically found in cattle, called M. Bovis, prefers a higher body temperature than the human strain.

Even though it has one confirmed case of bovine TB, Manitoba is still considered to be TB free under the federal Health of Animals Regulations. Canada’s status for international trade of animals and animal products is not affected by the case. Ontario is also considered to be TB free. The last time bovine TB was found here was in a dairy cattle herd in Peterborough County in 2002.

For most countries that are classified bovine TB free, some transient positives in the domestic animal population are considered acceptable. “We have an eradication and surveillance program in place so that’s why we get that status,” says Dr. Skippon. “For some other countries that don’t have those in place they’re not given the same status.” BF