Can the ‘Zombie deer disease’ spread to humans? All about the CWD infection as Yellowstone National Park reports cases

Chronic wasting disease (CWD), more popularly known as the Zombie deer disease, is raising plenty of concern, especially after Yellowstone National Park reported a case of an infected adult mule that was found dead in the park. At the moment, there are no cures or treatments for the condition, which leads to the deterioration of the brain and eventually death.

The symptoms of the disease, which is caused due to prions or misfolded proteins, may take a year to be identified. Currently, no cases of Zombie deer diseases have been reported among humans. However, the CDC insinuates that the disease can become a threat to people.

---

The Zombie deer disease gradually destroys the brain

Chronic wasting disease or Zombie deer disease affects deer, elk, and moose. A Chronic wasting disease infection will always end in death. However, symptoms of the disease may take a year to be visible. The disease is caused by the accumulation of prions or misformed proteins in the brain of the affected animal.

The accumulation of prions in the brain and different body parts leads to a variety of changes in the physiological and behavioral state of the animal. According to the CDC, some of the symptoms of the disease are stumbling, listlessness, drastic weight loss, and further neurological symptoms.

National Geographic explains that the disease causes apathy and motor incoordination while gradually destroying the animal's entire nervous system. At one point, the animal will look like a Zombie, with drooping ears, teeth clattering, excessive drooling, and head tremors, thereby giving it the name Zombie deer disease.

Zombie deer disease is a contagious disease. Prions from the affected animal can spread to another through consumption of the affected animal and by coming into contact with the body fluids (urine, blood, saliva, or feces) or the brain fluids of the affected animal, either directly or indirectly through environmental contamination.

Bovine spongiform encephalopathy is another famous prion disease. It is commonly referred to as mad cow disease. CWD comes from the same family of neurodegenerative disorders as mad cow disease. Although mad cow disease does not directly affect human beings, its variant, Creutzfeldt-Jakob disease, leads to the gradual destruction of the human spinal cord and the brain.

To this day, there have not been any reports of CWD affecting human beings. However, the CDC still asks people to be cautious as studies indicate that the diseases pose a risk to certain "non-human primates" who eat affected animals or come into contact with affected body fluids. Experiments have shown that CWD prions can affect squirrel monkeys and lab mice that have some human genes. The CDC warns:

"These studies raise concerns that there may also be a risk to people."

414 counties in 31 states reported CWD in free-ranging cervids as of November 2023 (Image via CDC)

WHO has recommended since 1997 to keep all agents of every known prion disease off the human food chain. CDC reported that 31 states in the United States and three provinces of Canada have reported cases of CWD.

---

Yellowstone detects its first case of Chronic Wasting Disease

In mid-October 2023, an adult mule deer buck was found dead near Yellowstone Lake in the southeast section of Wyoming's Yellowstone National Park. After lab testing, it was found that the animal had tested positive for Chronic Wasting Disease (CWD) or Zombie deer disease. The National Park Service (NPS) released a statement confirming the presence of the disease. The statement exclaimed:

"This is the first confirmed positive detection of the disease in Yellowstone National Park."

The dead deer had originally been captured by Wyoming Game and Fish Department (WGFD) officials in March 2023. It was tagged and equipped with a GPS collar for a "population dynamics study." The collar revealed that the animal died in mid-October, after which its carcass was located on the Promontory. Samples were then taken for lab testing, and the statement confirmed:

"The samples tested positive for CWD based on multiple diagnostic tests performed at WGFD’s Wildlife Health Laboratory."

Since Yellowstone is an extremely popular hotspot for travelers, NPS warned visitors to avoid "sick or dead wildlife" if they see any and immediately report the same to an NPS employee. The service especially told people not to have any physical contact with such animals as "disease-causing organisms" can be passed on from the animals.

Yellowstone National Park put out a warning (Image via X/@YellowstoneNPS)

Although NPS specified that there was no evidence that the Zombie deer disease could be transmitted to humans, it particularly recommended people not consume body parts of animals suspected to be CWD positive.