Chronic Wasting Disease in deer not a known threat to humans
A female deer in Minnesota preliminarily tests positive for Chronic Wasting Disease (CWD), that officials say is not known to affect human heath.
The disease is a fatal form of encephalitis that infects deer, elk and moose, causing the animals to lose balance and walk repetitive courses. In late stages, drooling and excessive salivation occurs, according to information from theChronic Wasting Disease Alliance. Though there is no known threat to humans, the CDC recommends against consuming the meat of infected animals.
The Minnesota Department of Natural Resources notes the deer testing positive for the disease was harvested November, 2010 a few miles southwest of a former domestic elk farm. Of 524 deer tested in the area, only one was found to have the disease.
Michelle Carstensen, the DNR’s wildlife health program leader, said the prevalence of CWD is likely low. “We sampled 524 deer this past hunting season in the Pine Island area and found only one that appears to have CWD."
No evidence of the disease was found in 2,685 samples taken throughout southeastern Minnesota in 2009 or 500 samples taken in 2008 along the Wisconsin border, from Houston County northward to St. Croix State Park in Pine County.
Though there is no evidence that CWD causes human disease, the CDC advises against eating venison known to be infected. The Minnesota Department of Natural Resources recommends those with venison in the freezer harvested from the area should be aware, and "will need to make decisions based on the information" that is guided by the Minnesota Department of Health.
How Chronic Wasting Disease is transmitted is not entirely clear, and there is no treatment. The goal and challenge for wildlife officials is to control the spread of the disease. The challenge is that it takes years to manifest from time of infection until symptoms appear.
Though Chronic Wasting Disease is not a human health threat, there are some similarities between the disease seen in animals and forms of human encephalitis. In vitro studies show the disease poorly adapts to humans.
Though CWD is not known to affect humans, the Chronic Wasting Disease Alliance recommends, "In the absence of complete information on risk, and in light of similarities of animal and human TSEs ( transmissible spongiform encephalopathies), public health officials and wildlife management professionals recommend that hunters harvesting deer and elk in the endemic area, as well as meat processors and taxidermists handling cervid carcasses, should take some common sense measures to avoid exposure to the CWD agent and to other known zoonotic pathogens." They add, "boning game meat is recommended as an effective way to further reduce the potential for exposure."
The impact of Chronic Wasting Disease poses problems for wildlife managers. The risk to humans has never not been documented, but hunters and those with venison in the freezer are advised not to eat meat from known infected deer. Public Health Officials recommend precautions for anyone handling deer carcasses, due to lack of complete information and similarities found in animal and human variants of CWD.
From the CDC, as an addendum:
"The lack of evidence of a link between CWD transmission and unusual cases of CJD, despite several epidemiologic investigations, and the absence of an increase in CJD incidence in Colorado and Wyoming suggest that the risk, if any, of transmission of CWD to humans is low. Although the in vitro studies indicating inefficient conversion of human prion protein by CWD-associated prions raise the possibility of low-level transmission of CWD to humans, no human cases of prion disease with strong evidence of a link with CWD have been identified."
..."provided sufficient exposure, the species barrier may not completely protect humans from animal prion diseases."
"Hunters should avoid eating meat from deer and elk that look sick or test positive for CWD. They should wear gloves when field-dressing carcasses, bone-out the meat from the animal, and minimize handling of brain and spinal cord tissues. As a precaution, hunters should avoid eating deer and elk tissues known to harbor the CWD agent (e.g., brain, spinal cord, eyes, spleen, tonsils, lymph nodes) from areas where CWD has been identified."
This page is updated on April 18, 2013.