While humans continue to battle a pandemic, a fatal disease has emerged that affects North Carolina’s white-tailed deer, reindeer and elk.
The state’s Wildlife Resources Commission identified a case of chronic wasting disease, a neurological disease that affects some types of cervids, in late March, prompting officials to enact an emergency plan to contain the disease.
The disease is spread by prions, abnormal proteins that are difficult to remove from the environment and can survive both extremely high and freezing temperatures. The commission detected the disease in a deer killed in Yadkin County in December.
Officials are working to boost monitoring capacities and speed up the time it takes to receive testing results.
Hunters in parts of the state near where the infected deer was harvested will face stringent regulations as the state works to see whether more cases are revealed.
North Carolina was fortunate to discover the disease so much later than many other states, Brad Howard, chief of the Wildlife Management Division, said.
“We’ve got the luxury of looking back through time at things that didn’t pan out well for other states,” Howard said.
What is chronic wasting disease?
The disease was first discovered in Colorado in the late 1960s and spread to states around the country in farmed and wild cervids. North Carolina first began monitoring for chronic wasting disease in 1999.
“They’re not like a virus or bacteria,” said Moriah Boggess, a state deer biologist with the N.C. Wildlife Resources Commission, during a public forum in Yadkinville on May 2.
“You can’t cure them. You can’t kill them because they are essentially just material. We are all made up of proteins, and so there’s no way to kill those proteins.”
As of January, the national Centers for Disease Control and Preventio said the disease had been found in at least 27 states and in Canada, but in March, North Carolina became the 29th state to find it.
Chronic wasting disease significantly shortens the life span of an ill deer. Infected deer may not show symptoms for over 18 months, and the prions can be shared by urine, saliva and body tissues, according to the commission. An infected deer can seem healthy but leave prions in the environment long before it dies.
In the case of the infected deer in Yadkin County, Boggess said there were no signs it was ill.
“The hunter was very helpful when we talked to them about the deer,” Boggess said during the public forum. “The deer acted normal. There were no visible signs that the animal was infected. It looked like a healthy 2 1/2-year-old buck like you would see out in the woods.”
Because it was the first case in the state, the Wildlife Resources Commission used a DNA sample to confirm that the deer it had was the one the lab found had tested positive, Boggess said.
When a deer eventually does show symptoms, they can be dramatic.
According to the commission, the deer may display “Isolation from other animals, listlessness or showing little or no interest in their surroundings, lack of coordination, frequent lowering of the head, blank facial expressions, walking in set patterns, drooling and grinding of teeth, drinking lots of water and increased urination, (and) low weight.”
Boggess cautioned against assuming a deer with any of those symptoms has chronic wasting disease, as the deer could be suffering from another issue.
He contrasted chronic wasting disease and epizootic hemorrhagic disease, also called “blue tongue” or EHD.
“EHD is endemic to the Southeast, meaning it’s been here for hundreds of years,” he said.
“As long as people have been monitoring deer populations, they’ve noted EHD outbreaks. Yet we still have a thriving deer population because white-tailed deer in southeast North America are adapted to EHD, or blue tongue.”
EHD, unlike CWD, is not always fatal, and animals that survive EHD have immunity for years, he said.
Boggess warned that the prevalence of chronic wasting disease is expected to increase in future years, infecting more and more animals. There is no recovery from the disease, and there is no current vaccination or treatment, he said.
Moving to humans or other animals
At a public hearing in Yadkinville, officials said a common concern seems to be whether dogs or other animals can become ill after exposure to the prions.
It is not known to affect dogs, according to Dr. Catherine Harris, director of livestock programs for the N.C. Department of Agriculture and Consumer Services.
“Typically, these transmissible prions do not cross species,” Harris said during the forum.
“Even within cervids, there are nonsusceptible species of cervid, so it’s very unlikely it would cross from cervids into our domesticated livestock species.”
Still, deer should be tested before consuming them, especially if they are within the primary surveillance zone established near the location where the infected deer was harvested.
There have been no known cases of prions affecting humans who handled an infected carcass or ate meat from a deer with the disease, but experts say that too much is still unknown to deem it safe for consumption.
“Some animal studies suggest CWD poses a risk to certain types of nonhuman primates, like monkeys, that eat meat from CWD-infected animals or come in contact with brain or body fluids from infected deer or elk,” the CDC states.
“These studies raise concerns that there may also be a risk to people.”
At least 15,000 infected deer are eaten every year in the United States alone, while the risks are still a mystery, according to University of Minnesota researchers who study the disease and its possible effect on meat.
Preventing spread in NC
The commission established two zones to monitor animals for possible infection: The primary surveillance area includes parts of Yadkin and Surry counties; and the secondary surveillance area includes all of Surry, Yadkin, Davie, Forsyth, and Stokes counties and part of Alleghany, Wilkes and Iredell counties.
The zones were set after considering the dispersal distance of bucks, Boggess said at the forum.
“Dispersal is the act of young deer leaving the home range where they were born and traveling some distance to a new location where they establish a new home range for the rest of their life,” Boggess said via email.
On average, bucks disperse up to 5 miles from where they are born, making it likely the infected deer harvested in Yadkin was born locally.
Does may also disperse for similar distances but do so less commonly than bucks, according to Boggess.
Hunters in the surveillance areas will have to follow rules from the emergency response plan the commission instituted in mid-April.
Among other requirements, the rules bar the removal of deer — dead or alive — from the surveillance zones unless they meet certain requirements, including cleaning the animal and removing meat from the bone in particular ways.
The rules also require hunters to test deer from the PSA during blackpowder season (Nov. 5 though Nov. 18) and gun season (Nov. 19 through Jan. 2) and during blackpowder season and from Nov. 19-27 in the SSA. Testing is also encouraged at other times and locations.
Getting test results back takes time. While the state now reports that it has tested all samples from hunters, there is a delay after hunters submit a sample, resulting in the state not learning about the positive case until March.
“The hunter kept the deer in the local area where it was harvested and disposed of the carcass in a manner that is recommended by the agency to reduce the chance of accidentally spreading the disease,” Boggess said via email.
“This is excellent news since the positive test result was not returned until months after the deer was harvested and the carcass had been disposed of.”
Mineral licks, bait or other food used to lure animals are barred from Jan. 2 through Aug. 31 in the surveillance areas with limited exceptions.
“I can’t think of a better way of spreading these prions than putting stuff in the dirt that we’re asking deer to come and lick,” Howard said.
The state is trying to increase the number of certified processors and taxidermists who can assist with the commission’s Cervid Health Cooperator program, Boggess said. The commission will also offer additional voluntary testing and staffed check stations to ensure hunters have access to them.
What happens next
Because chronic wasting disease shortens the life span of deer, there is concern about the implications for the future of the deer population in North Carolina.
“Population level effects from CWD infection will take generations to begin to surface,” Boggess said via email.
During the public forum, Boggess said 32% of does and 45% of bucks harvested in North Carolina are 3 1/2 years or older.
“So a fawn that’s positive, it’s only a couple of months old,” he said. “It only has 16-24 months after being infected before it’s going to die from the disease, which doesn’t give that much time to successfully reproduce. … In the long term, this can drive the population down.”
There is a strong likelihood that this will be a “rapidly changing situation,” said Chris Kreh, assistant chief for the N.C. Wildlife Management Division. He advised that there could end up being more regulations and surveillance zones if new cases are identified.
“We’re in a good place as far as having to deal with this,” state Rep. Jay Adams, R-Catawba, said at the forum. “We’ve got the cooperation of Virginia and Tennessee and all of the other states that are affected by it.”
Adams said the legislature appropriated $500,000 to make it possible to find infected deer like the one discovered in Yadkin County.
“The WRC is also working to reduce the turnaround time for CWD testing by working with the N.C. Department of Agriculture and Consumer Services to establish in-state CWD testing,” Boggess said in an email.
Cameron Ingram, executive director of the Wildlife Resources Commission, stressed the importance of public involvement in helping to control the spread of chronic wasting disease, noting that the actions taken today would affect generations to come.
In addition to public forums, information about the disease, hunting regulations, clarification about the surveillance zones, details about obtaining testing and updates can be found on the commission’s website. Those with concerns about a deer can call the commission’s helpline at 866-318-2401.