So-called "Zombie Deer Disease", also known as chronic wasting disease (CWD), is currently spreading among deer, elk, and moose in the USA. Hundreds of animals are estimated to have been affected by the disease last year – and as it spreads, experts are questioning if the illness could spread to humans.
As a prion disease, CWD behaves similarly to “mad cow disease” – or bovine spongiform encephalopathy (BSE) – in that it can take over a year before an infected animal shows symptoms. The most common signs include dramatic weight loss, an unsteady gate, and lethargy, hence the comparison to zombies.
One of the key risks of contagion for prion diseases is consuming infected meat. In the case of BSE, ingesting infected beef could cause the human form of the same disease known as Creutzfeldt-Jakob disease (CJD).
CJD is rare but fatal, presenting with brain damage that rapidly worsens, and while possible treatments are being explored, there’s currently no known cure for the disease. So, while cases are rare, they represent a considerable threat due to the severity of the disease.
It’s wise, then, to be wary of another prion disease, as while there’s not yet been a single reported case of CWD in humans, the risk of a disease leaping across species in this way can increase as its spread does. Prions can mutate, and these mutations can be good or bad in terms of public health.
As we saw with SARS‑CoV‑2, the virus that causes COVID-19, some mutations made the pathogen more contagious and deadly, while others reduced its potential. The same could be true of the prions that cause CWD.
Epidemiologist Dr Michael Osterholm who studied the outbreak of BSE described CWD as a “slow-moving disaster” to The Guardian. “We’re dealing with a disease that is invariably fatal, incurable and highly contagious,” added Osterholm’s colleague Dr Cory Anderson. “Baked into the worry is that we don’t have an effective easy way to eradicate it, neither from the animals it infects nor the environment it contaminates.”
The Centers for Disease Control and Prevention has outlined guidelines for preventing the spread of CWD, particularly among hunters who kill, carve, and consume the affected animals. The key points center around never eating the meat of animals acting strangely, and getting carcasses tested when they’re killed in an area where CWD is known to be spreading.
For more advice on the signs, symptoms, and areas affected by zombie deer disease, visit the CDC website.
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