Researchers say deadly disease could infect Northern caribou

A contagious, fatal and incurable disease killing deer in Alberta could infect Northern caribou, researchers say.

Chronic wasting disease (CWD) is a disease of the nervous system that infects mule deer, white-tail deer, elk, reindeer and moose. The symptoms, which can take up to 36 months to surface, can include weight loss, drooling, drooping ears, and paralysis as the infected animal's brain is damaged by the disease.

The disease can be carried in an animal's urine, feces, saliva, and milk causing direct or indirect transmission from animal to animal. Females can also pass it on to their offspring.

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Though there are no cases of CWD in caribou to date, work has been done that shows caribou can contract the disease, says Debbie McKenzie, an associate professor in the department of biological sciences at the University of Alberta in Edmonton.

McKenziesays this is problematic since there's a herd of caribou close to a herd of infected deer, near the southern part of the Northwest Territories at the Alberta-Saskatchewan border.There are also areasin central Alberta and Saskatchewanwhere CWD-positive deer are close to the southern range of caribou.

"The concern is that if [CWD] gets into the caribou herds ... they migrate much greater distances than mule deer and white-tail deer, so it's more likely that it could move into those [Northern] populations," she said.

McKenzie confirmed some infected deer populations have shown population declines.

"There are a few reported herds of mule deer and elk where they are actually starting to see population decline due to CWD," she said.

She fears northern caribou populations could suffer the same fate, if infected.

CWDin humans

The University of Calgary and the Canadian Food Inspection Agency have been studying the possible impacts of CWD on humans, using monkeys as test subjects due to their genetic similarities to humans.

Some monkeys brains are injected with the disease, while others are fed muscle tissue from a deer that had CWD. Though the study is not complete, researchers have found some monkeys were infected with the disease.

"They had problems in moving. Some were quite anxious. Some were very slow and sluggish and others were losing quite a lot of weight," said Stefanie Czub, a pathologist andresearch managerwith the Canadian Food Inspection Agency, and leader in her field.

In Alberta, 685 animals have been infected since 2005, but the number of cases detected in 2016 was double those detected in 2015. Czub also said there are places in the United States where CWD has been around for a while and 30 to 40 per cent of deer have contracted the disease.

Czub said Health Canada and the Public Health Agency are familiar with the results of her study and urge provinces and territories to test animals for CWD. She also said anyone who hunts and eats animals, should watch out for symptoms and warning signs of CWD before consuming it.

As of now there is no cure for chronic wasting disease, but researchers are looking for a vaccine.

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