Chronic Wasting Disease in Our Area
An issue of USA Today published two weeks ago suggested that two hunters may have contracted Chronic Wasting Disease (CWD) by eating venison. The article did not say where the men were from, only that, “Researchers at the University of Texas Health Science Center at San Antonio had reported that both men developed Creutzfeldt-Jacob disease (DJD) which is a neurological disease similar to mad cow or chronic wasting disease.”
The article said, “The patient’s history, including a similar case in his social group, suggests a possible novel animal-to-human transmission of CWD, they wrote in the case report, which was presented earlier this month at the annual meeting of the American Academy of Neurology and published in the peer-reviewed journal Neurology.”
The CDC says that prion diseases, which include Mad Cow Disease, Chronic Wasting Disease and Creutzfeldt-Jacob Disease are caused by misfolded proteins.
“Prion diseases or transmissible spongiform encephalopathies (TSEs) are a family of rare progressive neurodegenerative disorders that affect both humans and animals. They are distinguished by long incubation periods, characteristic spongiform changes associated with neuronal loss, and a failure to induce inflammatory response.
The causative agents of TSEs are believed to be prions. The term “prions” refers to abnormal, pathogenic agents that are transmissible and are able to induce abnormal folding of specific normal cellular proteins called prion proteins that are found most abundantly in the brain. The functions of these normal prion proteins are still not completely understood. The abnormal folding of the prion proteins leads to brain damage and the characteristic signs and symptoms of the disease. Prion diseases are usually rapidly progressive and always fatal.” (CDC website)
According to Shane Roberts, PhD, Wildlife Bureau Chief of the Idaho Department of Fish and Game (IDFG), in our area the most deer to have CWD are located in Slate Creek, just north of Riggins. He said about four percent of mule deer and about thirteen percent of white tail deer in that drainage had the disease as of last fall.
He also said that one deer just south of New Meadows in Adams County tested positive for the disease, and it is not known whether that deer wandered away from the herd in Slate Creek.
There is no treatment or cure for CWD, and it is always fatal. There are no vaccines.
Roberts said, “Feces from deer, elk or moose can contain prions, which are folded proteins that cause the disease, and may contain prions months before an animal exhibits symptoms. And while animals who prey on infected deer or elk or moose, won’t themselves get the disease, the prions can be in their feces as well. And even more worrying is that the feces of these animals seep into the dirt and any plants in that area will absorb the prions for up to sixteen years.
So those prions in plants can be transmitted to animals that eat the plant.
So far, the CDC says there is no known case of humans getting CWD from eating animals that have the disease.
In the 1980’s and 1990’s when the UK had an outbreak of mad cow disease (another fatal prion disease) the only way the government could contain it was by killing 4 million head of cattle. Also, 178 people died from the disease. (About BSE (Bovine Spongiform Encephalopathy) Prion Diseases, published by the CDC)
A small number of Mad Cow Disease cases continue to occur in the UK, but measures have been in place for many years to prevent the disease, such as a complete ban on feeding animal protein to livestock, which has been in place since 1996. https://aphascience.blog.uk
Andy Nutting, an epidemiologist with Southwest District Health, said the article in USA Today indicated that two men died of Creutzfeldt-Jacob disease after eating venison in an area known to have chronic wasting disease, but that those animals were not tested for the disease, so it is not possible to say that the men died from eating venison that had CWD.
Nutting said, “Currently, there is no concrete evidence that Chronic Wasting Disease is transmittable to humans. However, CWD is similar to a prion disease in humans called Creutzfeldt-Jacob Disease. The similarity between the two prion diseases is why we are so concerned about CWD, because there is a potential for it to jump to humans,” he said.
Roberts said that during the next deer and elk hunting season, IDFG will increase the number of check points in our area, so tissues samples can be taken. Tissue samples of deer, elk, or moose hunters have harvested may be taken to any IDFG office or drop point.
Roberts said test results usually take from four to six weeks, and he recommended that hunters not eat any deer, elk, or moose until they receive those test results.
The IDFG website shows how to harvest lymph nodes for testing, it also states that hunters will not be notified unless the animal they killed tested positive for CWD.
According to the CDC, CWD was first identified in captive deer at a Colorado research facility in the late 1960’s and in free-ranging deer by 1981. Now the disease has affected deer, moose, elk, reindeer, and caribou in 32 states, 4 Canadian Provinces, Norway, Finland, and South Korea.
Antelope do not get the disease.
