There’s never been a case of chronic wasting disease in the Yukon, and the territorial government wants to keep it that way.
The disease, also known as CWD, is a form of transmissible spongiform encephalopathies – the same family of disease that cause “mad cow” and its human counterpart, Creutzfeldt–Jakob disease.
Unlike “mad cow,” there has never been a case of CWD infecting humans. But, to be safe, the Public Health Agency of Canada does recommend that people not eat infected animals.
Chronic wasting disease only poses an obvious danger to members of the deer family, which includes elk, moose, and caribou. The disease was first discovered on a Colorado deer farm in the late 1960s.
Since then it has spread across six states and into Alberta and Saskatchewan.
There is no treatment for CWD and efforts to contain the disease have largely failed, said Mary VanderKop, the Yukon’s chief veterinary officer.
“It’s been something that, once it gets established, it’s been relentless in its spread,” she said.
Thousands of wild and domesticated animals have been slaughtered on both sides of the border, and efforts have been made to track infected animals and to quarantine affected game farms.
More than $45 million had been spent as of 2011, but the disease has continued to spread.
Last week the territorial government introduced new regulations aimed at keeping the disease out of the Yukon.
Hunters are being asked to leave behind the heads, spinal columns and all the entrails of any animals they kill outside of the Yukon.
Deboned meat is still OK, and hides can be brought back if they are in a leak-proof container. Trophy heads are only allowed to be imported if all the meat, brains and other tissues have been removed first.
Parts of northern B.C. and the Northwest Territories are exempt from the new regulations, although that exemption could be quickly rescinded if CWD is discovered in either of those jurisdictions, said Kris Gustafson, the manager for enforcement and compliance for Yukon’s Department of Environment.
CWD is a serious disease.
It isn’t caused by a virus or bacteria, but by an infectious protein called a prion.
All proteins, including prions, are made up of folded chains of amino acids.
Prions are present all over the body and play a role in protecting nerve cells. New research suggests may also be involved in neurological development as well.
But that’s when they’re folded properly. When they’re folded abnormally they become an infectious pathogen that destroys brain tissue.
Animals with CWD might not show signs of disease for years, all the while they are shedding infectious prions in their saliva, urine and feces.
Prions survive very well in the environment, said VanderKop.
“It’s not killed by sunlight, it’s not killed by freezing, it’s not killed by environmental effects,” she said.
Prions will actually bind to soil, where they can survive for years.
In fact they become even more infectious when bound to clay, added VanderKop.
“It’s something that contaminates the environment long term,” she said.
Of the 66 game farms that were quarantined because of CWD, 12 of them were banned from raising any cervids (any members of the deer family) ever again because of the severity of the contamination.
Symptoms of CWD include drooling, trouble swallowing, depression, and other abnormal behavior.
Infected animals will often be found wandering on the side of the road and other places that they shouldn’t be, said VanderKop.
“They’re stupid,” she said. “They have basically holes in their brain and these are progressive and they become more stupid.”
The animals eventually end up starving, because they stop being able to recognize food, said VanderKop.
Eventually there will be fines set for violating the new regulations, but right now the focus is on educating the public, said Gustafson.
“This isn’t the type if regulation that people are going to intentionally want to not comply with … there’s no reason for it.”
Contact Josh Kerr at joshk@yukon-news.com