Canada: Deer-killing disease spreads farther in Alberta; reaches Calgary

[Pastor Dale Morgan]

Plagues, Pestilences and Diseases

Canada: Deer-killing disease spreads farther in Alberta; reaches Calgary
 
Within five years could be found at Edmonton’s outskirts and in Calgary
 
By Hanneke Brooymans,
Edmonton Journal
February 23, 2011
 


EDMONTON — Chronic wasting disease in deer has spread farther west into the province and within five years will likely be found at Edmonton’s outskirts and in Calgary, says a University of Alberta biologist.

Dave Coltman came to that conclusion after looking at the latest testing results and map posted by Alberta Sustainable Resource Development last week.

Altogether, 17 new cases were found in the nearly 4,200 deer tested since September 2010. That brings the total number of wild deer cases found in Alberta since 2005 to 91.

CWD is caused by a prion, similar to bovine spongiform encephalopathy, that causes deer to slowly waste away.

In the past two years, the government has relied on a hunter surveillance program to track the spread of the disease.

Government staff collect the heads of deer killed by hunters in specific wildlife management areas where past cases have been found. They also test deer hunted in areas close to past cases. Prior to that, they had also used an aggressive winter cull program to reduce the densities of deer in infected areas.

Coltman, a biology professor who studies CWD, said the most recent map of the cases shows there are four new ones in a new wildlife management unit. He said the disease, as expected, is moving along river valleys.

“Those are like superhighways for CWD and deer.”

There are likely many more cases that haven’t been found, he said.

“If we’re going to continue to have surveillance to guess where the leading edge of this thing is, we’re going to have to go another set of management units further west, particularly in the south. It’s at the gates of Calgary now, basically.”

Alberta Sustainable Resource Development spokesman Darcy Whiteside said the testing program is nearing completion for the season. When it wraps up, they will evaluate their disease management program to see how it might change next season.

There is no evidence that the disease in its current form can infect humans. But research published earlier this year out of the United States suggests that over time, as the strain adapts over successive generations in the wild, it could become progressively more transmissible to humans. The study, published in The Journal of Biological Chemistry, said the transformation could take years or decades, or might not even happen. But it also notes that it is likely that CWD prions are progressively accumulating in the environment, since they bind tightly to soil and can remain infectious for a long time.

Coltman said there’s a delicate line to walk when talking about the risks associated with the disease. He doesn’t want to sound alarmist, but he also said that everyone working in the field expects there will come a day when a new form of a prion disease evolves from CWD and it could become transmissible to humans. The public wants to know what the chance is that that will happen. “It’s a very small number. ... But the day that it does happen it will blow up. And people will say, ‘Holy cow, we let it go and now look where we are.’ ”

Some hunters, when they get a call telling them their animal was positive, say they’ve already eaten the animal and don’t care.

“We tell people you can store it in the freezer until you get the results, but the (U.S. Centers for Disease Control) has found no link between eating deer or elk and prion disease in humans,” Whiteside said.

The World Health Organization recommends a precautionary approach, though, and says any animal product known to be infected with any prion disease should not be consumed by humans.

“Personally, I’d think twice about eating a deer if I knew it was positive,” Coltman said.