Scientists have warned that a virus called “zombie deer disease” could potentially spread to humans after the first case was discovered in Yellowstone National Park last month.
The deadly brain virus that leaves animals confused, drooling and unafraid of humans could one day infect humans, some authorities have warned.
The alarm was raised after a deer carcass tested positive for chronic wasting disease (CWD) in Yellowstone National Park in northwestern Wyoming in November.
Dr. Cory Anderson told The Guardian: “The BSE (mad cow disease) outbreak in Britain was an example of how things can become chaotic overnight when there is a spillover event, for example from farm animals to people.”
According to the US Geological Survey, the virus has spread to more than 31 US states, two Canadian provinces and even South Korea in recent years.
Scientists have warned that the virus, dubbed “zombie deer disease,” could potentially spread to humans. A biologist removes lymph nodes from deer to test for chronic wasting diseases
The alarm was raised after a deer carcass tested positive for chronic wasting disease (CWD) in Yellowstone National Park in northwestern Wyoming in November
The infected buck's body was tracked to a peninsula on the southern edge of Yellowstone Lake via a GPS collar set up last March for a population dynamics study
“We're talking about the potential that something similar could happen,” said Anderson, the program's co-director at the Center for Infectious Disease Research and Policy.
He added: “No one is saying it will definitely happen, but it is important that people are prepared.”
According to Anderson, whose study focused on the transmission routes of CWD, the disease is “invariably fatal, incurable and highly contagious,” he said.
“The concern is that we have no effective and easy way to eradicate it, either from the animals it infects or from the environment it contaminates.”
CWD is a prion-borne disease similar to “mad cow disease” that can cause weight loss, loss of coordination and other ultimately fatal neurological symptoms in deer and related species.
The US National Park Service said last month: “There is currently no evidence that CWD can infect humans or domestic animal species.”
However, the federal agency warned game hunters in particular: “It is recommended not to consume tissue from CWD-infected animals.”
Chronic wasting disease (CWD) is a prion-borne illness similar to “mad cow disease” that can cause weight loss, loss of coordination and other ultimately fatal neurological symptoms in deer. Above: A deer killed by CWD, as identified by wildlife officials in Mississippi
According to the US Geological Survey, CWD has spread to over 31 US states, two Canadian provinces and South Korea
Samples from the body of the infected mule deer tested positive for CWD in multiple rounds conducted by the Wyoming Game and Fish Department (WGFD) Wildlife Health Laboratory.
Typical tests on living and dead animals involve sampling tissue from a creature's nervous system, either from the central nervous system, such as the spinal cord, or from peripheral systems, such as the retropharyngeal lymph nodes and tonsils.
Studies have shown the disease poses a risk to nonhuman primates, including monkeys, according to the Centers for Disease Control and Prevention.
“These studies raise concern that there may also be a risk to humans,” the agency said. “Since 1997, the World Health Organization has recommended that it is important to prevent the pathogens of all known prion diseases from entering the human food chain.”
Park officials in Yellowstone said they are working with WGFD to monitor the park's dead and live deer and other ungulates to better assess how widely CWD has spread in the national park.
Yellowstone National Park officials said the discovery prompted them to revise the park's 2021 CWD surveillance plan – a new protocol version is expected sometime next year.
CWD was first detected in mule deer in Wyoming in 1985 in the southeastern region of the state
The disease's arrival in Yellowstone marks the end of a decades-long spread westward across the state and to the national park site in the northwest corner of Wyoming
Park spokesman Morgan Warthin said Yellowstone also plans to increase its collaboration with WGFD to identify which areas of the park are at increased risk from the disease.
CWD was first detected in mule deer in Wyoming in 1985 in the southeastern region of the state.
The following year, the deadly brain disease was discovered in Wyoming elk, according to WGFD.
The disease's arrival in Yellowstone marks the end of a decades-long spread westward across the state and to the national park site in the northwest corner of Wyoming.
Wyoming wildlife officials had tracked the mule deer buck from March 2023 to October 2023, when his GPS tag indicated he had likely died.
Their search for his body led them to a landmass between the southern and southeastern arms of Yellowstone Lake known as Promontory.
North of the park, Montana state wildlife officials also assist in the efforts and monitoring of wildlife harvested by their state's local hunters.
A Montana Fish, Wildlife & Parks Region 3 spokesman, Morgan Jacobsen, told the Daily Montanan that many CWD cases have not yet been detected in the state's hunting districts bordering Yellowstone.
Jacobsen described the news as a “data point of interest,” but not one that would radically change Montana’s own CWD surveillance plans.
“We will continue our monitoring and communication with the park and continue to work with hunters as the primary management tool for CWD in Montana,” Jacobsen said.