CWD biologist gives update on disease
ROSE TOWNSHIP — Andrea Korman, CWD biologist for the Pennsylvania Game Commission, gave a brief presentation on the status of the disease in the state at this week’s annual meeting of the local Penn State Extension Office.
She said Chronic Wasting Disease, or CWD, is a fatal brain disease in cervid (deer) species, which include white tail deer and elk. Korman said there have been no cases found in the Pennsylvania elk population. She said the infectious prions that cause the disease can be spread through direct animal to animal contact via the urine, feces and saliva of the deer. She said there is no vaccine, treatment or immunity to the disease. She said the disease is chronic, and it can take 18 to 24 months for the deer to reach the stage where they look like something is wrong with them.
“Most of the hunters I have talked to that had a positive deer head had no idea. The deer was in perfect condition, sometimes the biggest deer in the group. You really can’t
tell by appearances alone. The only way to know for sure is to get the deer tested,” Korman said.
She said the disease is caused when a prion, a naturally occurring protein, is folded and becomes infectious. She said the disease is related to other brain diseases, such as mad cow disease, scrapie in sheep and Creutzfeld-Jakob disease in humans. She said the disease has been around since the 1960s and they still don’t know much about it. They know the prions can be ingested by predators, scavengers, plants and even be absorbed into the minerals of the soil and still remain infectious for potentially more than a decade. She said that though there has never been a confirmed case in a human, non-human primates have been reported to have been affected.
“Given what we know and don’t know, the Game Commission and the CDC recommend you do not consume infected meat. It is extremely important to limit exposure of this because we know that it is a pathogen and it has the potential to cross the species barrier. Currently, there is no evidence of humans contracting it, but we don’t want increase our exposure and give it more opportunities to adapt and cross the species barrier,” Korman said.
She said it was first documented in a captive deer in Colorado in 1967, and in 1981, a case was found in a free-ranging elk. She said it didn’t cross the Mississippi River until 2002, when Wisconsin documented its first case. She said 30 states and four Canadian provinces have detected CWD. She said Pennsylvania has been testing for the disease in 1998 and developed an interagency CWD response plan in 2003. She said the first case was confirmed in 2012 in a captive deer facility in Adams County.
She said every time they find a confirmed case, they put a Disease Management Area (DMA) around the affected area. She said in 2014, two cases at two captive deer farms in Jefferson County resulted in the creation of DMA 3. She said DMAs 5 and 6 were created in 2021 in Warren and near Brockway. She said DMA 6 was different because it is less than two miles from the elk range and they did not want to risk spreading the disease to the elk herd. She said DMA 7 was created in Lycoming County, and the area covered by DMA 2 has expanded; those changes will go into effect for the 2022 deer season.
She said the Game Commission response plan has four levels of containment: DMAs, which seek to limit the spread of the disease via humans by restricting the movement of high-risk parts; established areas, where CWD detections are consistent and recurring; enhanced surveillance units, areas within a DMA where additional surveillance of the disease is warranted and where the game commission has a sampling goal; and containment zones, small zones about a one-mile radius where the Game Commission focuses its management priorities. These are usually found on the leading edge of the spread.
She said the Game Commission has several strategies to help slow the spread. The first strategy is a ban on feeding deer. She said that if an infected deer comes into contact with other deer at a feeding spot, they all can be infected. She said a ban on urine-based attractant helps stop deer from congregating and there is no regulation on the manufacture of the attractants, so the attractant itself could spread the disease. One of the most well known is the ban on the movement of highrisk parts, such as the head, brain, eyes, tonsils, lymph nodes and spleen. She said these parts are where the prions gather the most and it is illegal to take them out of a DMA. Furthermore, these highrisk parts cannot be brought in from a state or province outside of Pennsylvania, as they all test at different levels, which makes it harder to determine where infected parts come from.
She said these parts, within the state, can be disposed of in household trash, and it is legal to leave them at the harvest site. She said cooperating processors and taxidermists have contracted with the Game Commission to dispose of the high-risk parts properly. She said deer can be taken to a cooperating partner even if they are outside of a DMA, and a list of cooperators can be found on the Game Commission website.
She said another strategy is to reduce the deer population, which will significantly reduce the transmission of the disease by eliminating overlapping family groups. She said this strategy is the best tool that they have in affected areas. She said this can be done by increasing hunter harvest via additional antler-less permits and DMA permits.
She said surveillance is an important part of their management areas, and called attention to deer head collection bins, which help the hunter feel comfortable with the meat they consume by getting it tested, as well as giving the Game Commission additional samples to test. A map of the deer head collection box locations can be found online. She recommended that hunters remove the antlers from the deer heads before they are deposited, as they will not be returned to the hunter and sometimes get stuck in the chute. She said results will be mailed as soon as possible, and can also be looked up online. She said that if a deer is found positive and not fit for consumption, you have the option to get a replacement tag. If a hunter chooses to get a replacement tag, the affected deer needs to be turned over the Game Commission, including the antlers.
She said there is a variety of CWD resources available on the Game Commission website.