Bovine tuberculosis has left the borders of Wood Buffalo National Park, putting cattle producers on alert

thumb bison tbPhoto courtesy by BK ThompsonBovine tuberculosis in Wood Buffalo National Park's wild bison has been a problem for decades. In more recent years, it has spread beyond the boundaries of the park, and is at risk of infecting Alberta's domestic cattle herds, according to Alberta Beef Producers.

If this happens, it could result in financial hardships and trade restrictions from the United States — like those that have already been imposed on Manitoba.

Bovine tuberculosis is a chronic respiratory disease that can infect almost every mammal. It isn't often seen in bison, which are endangered in parts of northern Alberta. The herd in Wood Buffalo National Park, which straddles the northeastern border of Alberta and the Northwest Territories, is one of the few infected bison herds in the world.

According to Todd Shury, wildlife health specialist for Parks Canada, symptoms of bovine TB can take many years to develop, but there is no cure for the disease in animals. In the late stages, the bison will become weak and emaciated, and they might develop a cough. If the sick bison aren't singled out as easy targets by predators such as wolves, they will eventually waste away and die.

After death, yellowish lesions called granulomas are often found in their lungs and lymph nodes. Shury estimated that 50 per cent of the roughly 5,000 bison in Wood Buffalo National Park are exposed to the dormant form of the disease, while 30 per cent are infected with the active form in their lungs.

Because no agricultural lands share borders with Wood Buffalo, there isn't much threat that the disease, which spreads most easily through nose-to-nose contact, will leap directly from its bison to domestic cattle.

However, bovine TB has spread to an intermediate step: the wild bison between the park and the surrounding agricultural zones.

According to Shury, there is an infected herd in the Slave River lowlands of the Northwest Territories, and another in Alberta, in the Wentzel Lake area on the southeast boundary of the park. It's those herds that could bring the disease to the province's cattle.

But steps are being taken to prevent the spreading of bovine TB. Shury said that in the park itself, both the bison's movements and their reproductive rates are closely monitored, and bison-free areas — sections of land that bison are killed if they enter — have been set up around the herds to protect the agricultural zones near Fort Vermillion and La Crête.

One such "line in the sand," as Lyle Fullerton called it, is Highway 35, which runs from High Level to the Northwest Territories border.

Fullerton, who works with Alberta Environment and Sustainable Resource Development, helps co-ordinate bison management in the Hay-Zama Lakes Wildlands Park. Tucked into the northwest corner of the province, Hay-Zama is home to a herd of wild bison that are currently TB-free — and Fullerton would like to keep them that way. In an effort to protect the Hay-Zama bison, any bison between the Highway 35 and Wood Buffalo National Park are not protected under the Alberta Wildlife Act. That means that, unlike in most other parts of the province, the bison in that area can be killed without regulation.

If the two herds were to come into contact, it is almost inevitable that the Hay-Zama bison would become infected, increasing the risk of eventual cattle contamination.

Dr. Allan Preston is the bovine TB co-ordinator for Manitoba's Riding Mountain National Park, which has dealt with the disease in its elk population. He said that, if it were to spread to Alberta's domestic cattle herds, all it would take is one cow to test positive for TB for the entire herd to be sent to the slaughter, even if the rest are healthy. This would put enormous strain on farmers and producers.

It sounds like an extreme measure, but over the decades that bovine TB has persisted in Canada, complete herd depopulation — rather than just removing individual affected cattle — has proven to be the only sure way of controlling the disease, especially since bovine TB is capable of affecting humans as well as animals, and can be fatal if left untreated. However, there is minimal risk of humans contracting the disease from bison or cattle meat and milk, as pasteurization and medical treatments are readily available in the developed world.
If it does spread to cattle, bovine TB has the potential to cause major problems for Alberta cattle farmers. According to Karen Schmidt, a representative of Alberta Beef Producers, the main concern would be the trade restrictions that would be imposed if the disease spread to healthy cattle.

"If we had a case of TB in the cattle herd, that herd would have to undergo quarantine," she said. "After that it's possible that our trading partners may put some testing requirements on any cattle being exported. If they put in more testing requirements, that's added cost."
According to Dr. Kevin Steinbachs, this is already happening in Manitoba. Farmers in that province have to pay an extra $7 to $15 per head for testing before they can export breeding cattle to the United States.bison mapThis map shows the various locations of bison herds around Wood Buffalo National Park. Photo courtesy of Alberta Evnironment and Sustainable Resource Development

Steinbachs is one of many vets who handle that testing, which is the result of the history of the disease in Riding Mountain National Park's elk.

"It's extra expense and time that no one else has to worry about," Steinbachs said.

That is why bovine TB is such a cause for concern in Alberta, and why the group representing its cattle industry is worried. Alberta's beef industry outstrips Manitoba's by a sizeable margin, having shipped over four times as many head of cattle the United States alone in 2012.

Beef is also Alberta's most robust agricultural resource, having generated $3.4 billion in farm cash receipts that same year, according to Statistics Canada.

Karen Schmidt said that while the health of Wood Buffalo's bison is a secondary priority, her organization's first concern is the province's commercial cattle herds.

"The risk is there and we have to take steps to minimize that risk as best we can," she said. "Ideally, we would depopulate (Wood Buffalo) and then repopulate with clean bison out of Elk Island or Hay-Zama, but I'm not sure if that is a strategy that would be acceptable to the rest of the stakeholders."

It very likely wouldn't be. When that same fix was proposed after a study was conducted in the late 1980s, there was considerable resistance from the public, who didn't like the idea of killing 5,000 animals, diseased or not. If total depopulationwent ahead, not only would it be a difficult and expensive project to accomplish, it would also remove roughly half the remaining wood bison in all of Canada.

"It's a very divisive issue because people really value those bison up there, especially a lot of the local Aboriginal communities," added Todd Shury. "They still hunt those animals, and they've got a very strong cultural attachment to those herds."

Representatives of the Little Red River Cree Nation southwest of Wood Buffalo were unavailable for comment on the situation.

With so many different stakeholders, the problem of how to manage bovine tuberculosis remains contentious. There have been attempts in the past to determine a solution that would satisfy them all, none have been very successful. An updated wood bison recovery strategy is in the works, but has been sitting in a draft stage for several years as the various groups involved have been unable to come to an agreement.

The lack of progress on what would be a Canada-wide strategy for controlling bovine TB has been frustrating, especially for Shury.

"I used to say it will probably be released in the next year," he said. "I've been proven wrong so many times that I've given up trying to predict that.

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