The Canadian government has issued a warning to hunters and those that consume meat from deer, elk, moose and caribou that can transmit chronic wasting disease which is an incurable, and fatal illness. Even cat and dog food maybe at risk as the ingredients can include these species as a meat-by-product. Environews in a piece titled HEALTH ADVISORY: Venison, Elk May No Longer Be Safe to Eat — Study: Deadly Chronic Wasting Disease Could be Moving to Humans notes that the wasting disease “is one of several prion diseases (pronounced pree-on), of which the most well-known is mad cow disease, or bovine spongiform encephalopathy (BSE). The Centers for Disease Control (CDC) identifies six known animal prion diseases and five that affect humans. The most common prion illness in people is Creutzfeldt-Jakob disease (CJD)”.
Prions are abnormal, misfolded proteins. Lacking cell nuclei, they are not alive like bacteria, though they behave much like parasitic life forms as they replicate themselves by hijacking and misfolding otherwise normal proteins in the unfortunate host. They cause diseases that are collectively called transmissible spongiform encephalopathies, or TSEs. Such diseases commonly infect the brain and spinal cord, and are nearly always undetectable until symptoms arise, often years or even decades after infection. CWD was first identified in Colorado in the 1960s and has since spread to 24 states and two provinces in Canada. Small outbreaks have also occurred in South Korea and Norway.
It has long been believed that CWD is unlikely to infect humans due to the presence of a so-called “species barrier.” But BSE was also considered to be cordoned off until 1996 when Great Britain admitted, after years of denial, that mad cow disease had been transmitted to humans. Worldwide, 229 deaths have been reported. Those people were infected by eating meat or organs from disease-ridden cattle.
The research study began in 2009 with 21 macaques. The article goes through the clinical trials over the years. It is grisly for the animals of course, and I did not wish to share that portion here.
While most scientists would wait for the completion of their study and then submit the results to a peer-reviewed journal, Czub and her colleagues felt they couldn’t wait. “This whole experiment was done to generate data for a risk assessment of chronic wasting disease, and a risk assessment is always to protect human health,” Czub explained. “What we have so far is important enough to communicate it.”
The information was presented to the Canadian health authorities by the Alberta Prion Institute, which is funding the study. Health Canada, an organization described as “responsible for helping Canadians maintain and improve their health,” responded with its risk advisory.
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This is not just an issue that matters to people who care about wildlife,” Rowledge added. “This matters to everyone.” That’s because approximately 75 percent of new human pathogens in the past 25 years have originated in animals, according to a 2009 British study. That study goes on to note, “Greater risks to human health from wildlife pathogens appear to be inevitable as a consequence of increasing human contact with wildlife through greater access to, and disturbance of, wildlife habitats.”
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The Alliance for Public Wildlife estimates that 7,000-15,000 CWD-infected animals are consumed in North America each year. Rowledge explained they derived that figure through statistical analysis of deer populations in infected areas, the prevalence of infection and the number of animals harvested by hunters. But he cautioned that as state governments have cut back on testing, lack of hard data makes precise numbers difficult.
Testing of deer and elk kills is mostly voluntary, and usually comes at the request of hunters only when they suspect a diseased animal – typically from signs such as drooling or emaciation. “It’s not just that we don’t have enough precautionary measures to stop people from eating [these animals]; it’s that we’ve failed fundamentally to follow science and evidence in terms of containing the epidemic,” Rowledge said.
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There are caveats to Czub’s research, which she freely admitted. It is in-progress research, and the complete results will not be in for a few years. The study won’t be published in a peer-reviewed science journal until then. Additionally, two of the macaques in her study had diabetes, which Czub explained, lowers the level of insulin in the animal. Insulin is known to have a protective effect on neurons in the brain, thus potentially making them more susceptible to infectious prions.
But her study, which is funded at least through 2018, raises important questions about the potential for chronic wasting disease to show up in humans. She told EnviroNews that the scientific community may be overestimating the strength of the species barrier. “It’s something which I think we will need to be really dealing with.”
Rowledge was more blunt. “I don’t know what part of this isn’t a disaster unless we get in front of it.”