The Missouri Department of Conservation reported 46 new cases of chronic wasting disease (CWD) in the deer population on Wednesday during their monitoring and testing efforts in the 2019-20 surveillance year.
The new findings bring the total cases of CWD in Missouri to 162. The Missouri Department of Conservation confirmed 25 of the 46 new cases from nearly 29,000 tissue samples from white-tailed deer, which were mostly collected from hunter-harvested deer.
Missouri Conservation Department Northeast Regional chronic wasting disease coordinator Chad Smith said the monitoring program is done through hunters getting their harvested deer tested and a culling approach once deer season is over.
“The bulk of (the samples) come from the first two days of firearm season in those counties where we have mandatory sampling,” Smith said. “What makes those counties mandatory is they either had positive tests in the past or they are within close proximity within an area that's had positives in the past.”
It can take months or years for symptoms of CWD to show in deer and it is a fatal disease. Symptoms include excessive salivation, drooping head or ears, tremors, emaciation and changes in behavior.
The 46 new cases were found in the following counties; three in Adair, six in Franklin, one in Jefferson, eight in Linn, eight in Macon, two in Oregon, two in Perry, one in Polk, 10 in Ste. Genevieve, two in Stone and three in Taney.
“Most hunters are very familiar with the disease because Northeast Missouri is where we first detected chronic wasting syndrome in the state of Missouri,” Smith said. “That was in Macon County, and it's something we've been dealing with in Macon County for over 10 years now.”
Smith said the Missouri Department of Conservation culls deer from all parts of the state to get a snapshot on how prevalent CWD is within Missouri.
“In areas where we have the disease, after all the deer season are over, we have what we call a targeted culling approach,” Smith said. “Within very close proximity of where we have the diseases, we harvest additional deer form that area with the help of landowners, and test all of those as well.”
CWD cannot be confirmed until the deer is dead and a tissue sample can be taken for testing. All the deer harvested through targeted culling that tested negative for CWD are either returned to the landowner or donated to a local food pantry as part of the Share the Harvest venison donation program.
Smith said the Department of Conservation's approach is to try to detect CWD as quickly as possible to limit the spread. He added that culling can also help limit the spread of the disease.
“Part of that statewide testing component with our taxidermists is to try to get a distribution of samples across the state, and we've been successful in detecting the disease of the landscape by using that method,” Smith said. “Those deer brought to a taxidermist are usually mature bucks, which have a tendency to have a higher prevalence rate of the disease because they are generally older and more social.”
CWD is spread from deer to deer from direct contact and through contact with soil, food and water that have been contaminated by feces, urine, saliva or carcasses of infected deer.
The cause of CWD is from misshapen proteins called prions, which lead to a degenerative brain disease that eventually causes death.
“Deer are a social animal and live in family groups,” Smith said. “Generally in the summer, bucks travel together in what is called bachelor groups and the way they communicate is through scent, sight and smell. They are often grooming each other with nose-to-nose contact, licking each other, and that's how they communicate.”
The Missouri Department of Conservation has implemented new regulations on the transportation of carcasses to help limit the spread of CWD that took effect this year. Among the requirements are for meat processors and taxidermists to discard carcasses in a properly permitted landfill or a waste transfer station.
“(Deer carcasses transmissions) are less of a risk than deer-to-deer, but it's still a risk and one we can control as far as hunters and regulation,” Smith said. “We can't control which deer interacts with other deer, but we can control where a hunter takes their deer carcass after they harvest it.”