Study: Hunters Die After Consuming CWD-Infected Venison
A recent study in the journal Neurology found two hunters may have contracted the human form of Chronic Wasting Disease after eating CWD-infected deer meat
Zombie Deer Disease (CWD)
Occurrence | Chronic Wasting Disease (CWD) | Prion Disease | CDC
Chronic wasting disease (CWD) is a prion disease that affects North American cervids (hoofed ruminant mammals, with males characteristically having antlers).
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For years, chronic wasting disease (CWD), caused by prions – abnormal, transmissible pathogenic agents – has been spreading stealthily across North America, with concerns voiced primarily by hunters after spotting deer behaving strangely.
The prions cause changes in the hosts’ brains and nervous systems, leaving animals drooling, lethargic, emaciated, stumbling and with a telltale “blank stare” that led some to call it “zombie deer disease”. It spreads through the cervid family: deer, elk, moose, caribou and reindeer. It is fatal, with no known treatments or vaccines.
The disease is a “slow-moving disaster”, according to Dr Michael Osterholm, an epidemiologist who studied the outbreak of bovine spongiform encephalopathy, or “mad cow disease” – a related prion condition – in the UK, and is director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
Once an environment is infected, the pathogen is extremely hard to eradicate. It can persist for years in dirt or on surfaces, and scientists report it is resistant to disinfectants, formaldehyde, radiation and incineration at 600C (1,100F).
Jumping the species barrierIn the US and Canada, CWD has gained attention not only because it affects big-game animals but also because of the possibility that it could jump the species barrier. Deer, elk and moose could infect livestock, other mammals, birds or even humans. Epidemiologists say the absence of a “spillover” case yet does not mean it will not happen. CWD is one of a cluster of fatal neurological disorders that includes BSE.
The Alliance for Public Wildlife estimated in 2017 that 7,000 to 15,000 CWD-infected animals a year were unwittingly being eaten by humans, and that the number was expected to increase 20% annually. In Wisconsin, where testing of game meat is voluntary, Anderson and Osterholm say many thousands of people have probably eaten meat from infected deer.
Wyoming serves as a reference point for other states. Since 1997, there have been 92,000 tissue samples collected and tested there, said Breanna Ball, of the Wyoming Game and Fish Department. Last year, the meat from 6,701 deer, elk and moose was tested. Disease was present in about 800 samples, suggesting infection rates are rising.
“The science of what’s needed to help slow the spread of CWD is clear, and has been known for a long time,” Roffe says. “You don’t feed wildlife in the face of a growing disease pandemic.”
Especially problematic, he notes, is the controversial artificial feeding of wildlife by humans. In Wyoming, the state and federal government operate nearly two dozen “feedgrounds” for elk, where more than 20,000 animals are given alfalfa to help them survive the winter. The practice is condemned by leading wildlife management organisations.
Studies suggest that animals which some hunters regard as competitors may actually be allies. Wildlife predators such as wolves, cougars and bears are able to detect sick animals long before humans do, and they will prey on them, removing them from the landscape. So far, they have maintained immunity from disease.