Despite ongoing efforts to curtail its spread in the U.S. and abroad, the lethal chronic wasting disease (CWD) remains a threat — with no vaccine or cure.
In 2005, the “zombie deer” disease struck New York after several deer infected with chronic wasting disease (CWD) escaped from a fenced-in pen in Oneida County, a largely rural area in upstate New York.
Only a swift, aggressive culling operation by the New York Department of Environmental Conservation — resulting in the slaughter of hundreds of deer, with the cooperation of local hunters — was able to stop the outbreak.
To date, New York is the only state to have eliminated CWD from its population of deer, moose and elk.
But CWD has continued to spread worldwide, and many regions of the country are on the alert for the illness in wild and penned animals.
How chronic wasting disease develops
Chronic wasting disease is known to medical experts as a prion disease, a group of rare progressive neurological disorders that affect humans and animals.
Other prion diseases include Creutzfeldt-Jakob disease and bovine spongiform encephalopathy, also known as “mad cow disease.”
The disease causes sponge-like holes to develop in the brain of an infected animal, as well as affecting spinal fluid and other bodily tissues.
And though there have been no cases of CWD spreading to humans, some studies suggest that it poses a risk to certain types of primates that come in contact with body fluids from infected animals.
“These studies raise concerns that there may also be a risk to people,” the Centers for Disease Control and Prevention said in a 2021 report.
That same year, Pennsylvania reported an outbreak of CWD in deer just a few miles from the New York State border. As of this month, the CDC reports that the disease has been found in 31 states, as well as three Canadian provinces, northern Europe and South Korea.
How CWD spreads
Prion diseases like CWD have a long incubation period, which is especially troubling because an infected animal appears healthy for as long as two years before showing symptoms, during which time it can spread the disease to other animals.
CWD and other prion diseases are spread through bodily fluids and through contaminated soil, plants, food or water. As the disease progresses through the brain and nervous system, infected animals may show symptoms including:
Precautionary measures recommended
Hunters are asked to be on the lookout for deer, moose, elk or other members of the cervid family that show any of these symptoms.
Additionally, anyone dressing, skinning or butchering meat should wear nitrile, rubber or latex gloves.
To control the spread of CWD, New York and most other states have strict regulations against importing live deer and other cervids from outside the state, as well as prohibitions against importing carcasses and by-products.
People are also not permitted to feed wild deer because most human food is unhealthy for deer, and because concentrating the animals in one feeding spot can help to spread CWD.