Zombie Disease Detected in Yellowstone National Park

A rare "zombie" disease that causes deer to excessively drool, droop their ears and become reluctant to move before eventually killing them has been detected in Yellowstone National Park for the first time, officials say. Once established, officials say there is "no effective way to eradicate" the fatal illness, called chronic wasting disease.

National Park Service officials said earlier this week the disease was found in a dead adult mule deer found near Yellowstone Lake. The deer had originally been captured in Cody, Wyoming, by the state's Game and Fish Department in March as part of a population study, and according to a GPS collar that had been placed on the animal, officials said it died around mid-October. 

"This is the first confirmed positive detection of the disease in Yellowstone National Park," a press release from the government agency said, adding they conducted "multiple diagnostics tests" to confirm its presence. 

What is "zombie" deer disease, or chronic wasting disease?

Deer, elk, reindeer and moose can all be affected by chronic wasting disease, which has been found in North America, Norway and South Korea, according to experts. The disease, also known as "zombie deer disease," is a rare progressive neurodegenerative disorder that impacts prion proteins mostly found in brains.

When animals are infected with chronic wasting disease, it can take more than a year for them to show symptoms. Some animals may die without ever fully developing the prion disease. Symptoms include weight loss, reluctance to move, excessive salivation, increased drinking and urination, drooping ears, and eventual death.

The majority of animals infected with chronic wasting disease appear completely normal and healthy when harvested, according to experts.

The disease is typically transmitted through bodily fluids and waste, including saliva, urine, feces, and carcasses. Animals can also become infected if their feed or pasture is contaminated with the prions carrying the disease.

Currently, there is no effective strategy to eradicate chronic wasting disease once it has been established. Efforts are being made to identify areas at high risk for its spread and increase monitoring and sample testing. The surveillance plan for Yellowstone National Park is also being revised to address the disease.

Can humans get chronic wasting disease?

The Centers for Disease Control and Prevention (CDC) has stated that there have been no reported cases of chronic wasting disease (CWD) infection in humans.

However, there is still some concern about the potential risk. Studies have shown that monkeys can be at risk of CWD if they consume infected animal meat or come into contact with infected animal brains or bodily fluids.

The World Health Organization has recommended since 1997 that the agents of all known prion diseases, including CWD, should be prevented from entering the human food chain.

The CDC is also conducting additional studies to determine if prion diseases like CWD can occur at a higher rate in individuals who are more likely to come into contact with infected animals or their meat.

Due to the long incubation period of the disease, it may take many years before scientists can determine the true risk, if any, of CWD to humans.