A group of Canadian scientists is raising alarm over a fatal nervous system disease spreading in deer and elk, warning of the potential risks to human health and urging the federal government to take stricter measures to contain it.
Over the past few years, instances of chronic wasting disease (CWD) – a highly contagious fatal illness that is part of the same family as mad cow disease – have been increasing around the world, and in Canada, in Saskatchewan and Alberta. There have been no documented cases of the disease spreading to humans, nor is there direct evidence the disease can transfer to people.
Still, a group of experts sent a letter to the federal government this week warning of the “epidemic,” and asking that urgent measures be put in place. In particular, they fear the potential of the disease being transmitted to humans through eating infected meat.
“Chronic wasting disease presents profound threats to wildlife and the environment, to agriculture and international trade, to Indigenous rights, traditions, treaties, food security, and, potentially, to human health,” says the letter, sent Monday. The letter is signed by 34 individuals, including experts in human and animal health, as well as representatives of Indigenous communities, hunting groups and conservation organizations.
According to experts, instances of CWD have nearly doubled in recent years in Canada, to nearly 7 per cent of all tested animals in Alberta. Last year, the disease was detected for the first time in Quebec.
A recent study by Canadian Food Inspection Agency researcher Stefanie Czub, meanwhile, proved for the first time that the disease can be transmitted to macaque monkeys as a result of eating infected meat.
“There must be more emphasis on this disease, and that it’s really a potential threat that chronic wasting disease might jump the species barrier to humans,” said Hermann Schaetzl, a professor of prion biology and immunology in the University of Calgary’s faculty of veterinary medicine. “I think it’s a real concern.”
In a statement Tuesday, a spokesperson for the Canadian Food Inspection Agency said that “CWD is a complex disease to which there is not a simple solution.” Though there are “very few tools and approaches available” to control the disease, he said they have had some success through measures established since 2002 (and updated last year) at preventing the spread on farms.
The agency’s website also refers to a number of other precautionary measures it has taken. In recent years, the agency has released several warnings about the disease, including information specifically geared at hunters encouraging testing and urging against eating infected animals. But so far, most measures, like having animal carcasses tested before eating, have been voluntary.
The letter’s signatories say this response has been inadequate. They’re pressing for mandatory testing of all animals harvested from affected areas before consuming. They’re also urging that deer and elk not be moved from one place to another – both live animals and potentially infected carcasses.
“There’s a lot of science that’s unclear. But there’s a lot of science that’s demonstrated red flags and warnings to take a lot of precaution,” said Kat Lanteigne, the executive director at BloodWatch, an organization that monitors blood safety.
In particular, she said the government’s approach of spreading public awareness, mainly through its own website, has fallen short.
“What Canadian is going to that website?” she asked. “Ever?”
As a government scientist with the Public Health Agency of Canada, Michael Coulthart, head of the Canadian Creutzfeldt-Jakob disease surveillance unit (the human form of mad cow disease ), was not a signatory on the letter. But he agreed with the assessment that science is not yet conclusive on potential human risks.
“I wish I knew the answer. Nobody knows the answer,” he said. He said that evidence thus far seems to indicate that if the disease is transmissible to humans, that it’s not likely highly transmissible.
But he added, “it doesn’t have to be highly transmissible to be a concern for human health.”
In general, he added, “it makes sense to do everything we can to control the disease.”
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