Skip to content

Tag: prions

Published on Leave a comment on Has Deer Chronic Wasting Disease Occurred In Humans?

Well, it finally might have occurred. The always fatal neurologic disease known as chronic wasting disease (CWD),  which occurs in deer, elk, and moose, and is slowly spreading throughout the US and Canada, may have finally made the jump from deer to humans. This is very worrisome.

CWD is a prion disease similar to "mad cow disease" (bovine spongiform encephalopathy) in cattle and Creutzfeldt-Jakob's disease in humans. There is no vaccine, treatment, or cure for the disease.

In the recently published study, two friends, who hunted and consumed venison from an area known to have chronic wasting disease in the deer population - both died from Creutzfeldt-Jakob disease (CJD) in 2022. Doctors think this is might be a case of "cross-species prion transmission".

So far CWD has been detected in 33 states and several Canadian provinces, and so far nothing has been found to eliminate or slow down the spread of the disease. High heat, disinfection, radiation - these don't kill the CWD prions.

How is it spread? Scientists believe CWD prions spread between animals through body fluids (e.g., feces, saliva, blood, or urine), either through direct contact or indirectly through environmental contamination of soil, food or water. Once introduced into an area or farm, the CWD prion (protein) is contagious within deer and elk populations and spreads.

Once CWD gets into the soil, it stays there for years, and so animals can contract it even after infected deer and elk have died. Recent research found that plants uptake the prions, where it remains infectious.

From Medical Xpress: Consumption of contaminated venison suspected in cases of deer hunters with prion disease

A small team of medical workers and researchers in the U.S. has published a case study of two men, both deer hunters, who developed a rare prion disease. In their study, published in the journal Neurology, the group describes the symptoms of the two patients and how they died.

...continue reading "Has Deer Chronic Wasting Disease Occurred In Humans?"

Published on Leave a comment on Deer Population Could Decline From Chronic Wasting Disease

One topic of concern is chronic wasting disease and its slow spread throughout the US and Canada. Now found in 30 states! Chronic wasting disease (CWD) is a prion disease that has no cure and is always fatal. It is similar to mad cow disease, but this fatal neurological disease occurs in cervids, such as deer, elk, and moose.

Recently, The Atlantic had an article about the spread of chronic wasting disease, and how it could ultimately result in the extinction of deer in the US. Some estimates already have the deer population down several million (for several reasons, not just CWD). Or perhaps deer populations will get decimated, with only some deer living and reproducing until the age of 2, and then dying.

This is because the disease can be transmitted before symptoms appear. It takes a while (more than a year) for a deer to show symptoms and die, and it can be passed to newborn fawns from the mother deer when she uses her tongue to groom the newborn.

Incredibly, the disease particles are shed into the environment (e.g., from deer feces) and stay in the soil for at least a decade. It can even be taken up by plants (thus it's in the leaves that deer eat) from the soil.

And yes, if you're wondering, scientists are very concerned that some day this incurable prion disease can make the jump to humans. So far it hasn't, but this is one reason why hunters are told to bring in deer heads for testing (and definitely to not eat deer meat until results come back negative).  Unfortunately, many people resist believing that there is a problem, and testing efforts vary from state to state.

Excerpts from The Atlantic: An Incurable Disease Is Coming for Deer

Jorge is leading a multiyear study at the University of Georgia on chronic wasting disease, an always-fatal neurological illness. Ubiquitous deer may be, but in CWD, they face a serious threat. From its first appearance in Colorado in the late 1960s, CWD has crawled steadily across the country. It is now found in more than 30 states and multiple Canadian provinces. ...continue reading "Deer Population Could Decline From Chronic Wasting Disease"

Published on Leave a comment on Chronic Wasting Disease Now in 28 States

Yikes! Just two weeks later, a post has outdated information. Chronic wasting disease (CWD) is now found in 28 states - not 27 as I posted December 30, 2021. The additional  state where a wild white-tail deer has been found to have CWD is Alabama. Yes, the disease is spreading!

Chronic wasting disease is an always-fatal prion disease similar to "mad-cow disease" (bovine spongiform encephalopathy) in cattle. This disease is only found in cervids - deer, elk, reindeer, and moose. Medical opinion is that there is a species barrier, a "thin molecular barrier" preventing crossing over of the prion disease to cattle and humans.

Why the concern?  The concern is that this disease will jump to humans, especially in people who eat contaminated meat. No human cases have been detected, but health officials warn people to avoid eating meat from CWD infected animals.

Therefore hunters are advised to bring  hunter harvested heads of deer, elk, and moose for testing. In Alabama it's at drop-off freezer or sampling stations.

In chronic wasting disease there is a long incubation period, followed by the brain becoming progressively like a sponge - riddled with holes, along with deterioration in brain function, behavioral changes, and eventually death. A horrible slow death. There are no treatments or vaccines.

One scary thing about CWD is that once it gets into the soil, it stays there for years, and high heat, disinfectants, and radiation don't kill it. Yikes! Dr.Zabel at the Colorado State Univ. Prion Research Center suggested a few years ago that controlled burns (fires) of infected fields or areas could eliminate the prions left behind by infected animals (from animal mucus/saliva, urine, and feces, and decaying carcasses) on plants and soil.

An article with advice for how hunters can protect themselves, and a map of where CWD is found in the US.: 5 Ways Hunters Can Prevent Spreading Chronic Wasting Disease

A Chronic Wasting Disease Resource Center monitoring the situation and publishing information and research on its site is CIDRAP (Center for Infectious Disease and Policy). From the Jan. 14, 2022 news scan, CIDRAP:  With positive test in a deer, Alabama becomes 28th state to detect CWD

Chronic wasting disease (CWD) has been detected for the first time in Alabama, the Alabama Department of Conservation and Natural Resources (ADCNR) confirmed last week.  ...continue reading "Chronic Wasting Disease Now in 28 States"

Published on Leave a comment on Chronic Wasting Disease Does Not Spread to Cattle and Humans

After reading the recent post on the always fatal prion disease known as "chronic wasting disease" spreading in wild deer and elk in the U.S., a reader asked whether chronic wasting disease (CWD) is also found in cattle. Or whether it could cross over to cattle, and so wind up in the beef we eat. Excellent question.

The studies and medical discussions that I read all agreed that: chronic wasting disease is only found in cervids - deer, elk, reindeer, and moose. Medical opinion is that there is a species barrier, a "thin molecular barrier" preventing crossing over of the prion disease to cattle and humans. Several studies that specifically looked at this issue back this up. Whew, what a relief!

A 2017 study by Canadian researchers reviewed 23 studies looking at "transmissibility" of CWD to humans. They did not find any evidence of transmission of CWD prions to humans in the U.S or Canada, and no evidence supporting the possibility of transmission of CWD prions to humans. However, they did not rule out the possibility that a CWD prion more readily transmissible to humans could emerge over time given sufficiently extensive human exposure, or if a variation in CWD prion strains develops.

A good study by Univ. of Wyoming researchers actually had deer sick with CWD and healthy cattle living side by side for 10 years - sharing food, water, paddocks, and with constant interaction. Another group of 12 calves were given orally (by mouth) 45 g of prion tissue from CWD infected deer and kept indoors (2 per room) in an isolation building after that point. (Note that eating only 1 g of such prion tissue makes deer sick with CWD). There was also a healthy control group not exposed to CWD in any way. All brains were examined after death - and all cattle brains were normal.

Interestingly, this 2018 study did mention that if CWD prion material is injected into cattle brains (which was done in some other studies), then they do go on to develop CWD - but that is not how cattle would be exposed to it naturally. Which is why they did the study trying to mimic natural conditions in which any potential transmission could occur - and found no transmission of CWD.

But...scientists are concerned with possible transmission of CWD prions to humans occurring at some point, for example if variation in CWD prion strains develops. Keep in mind that CWD is spreading year by year throughout the US (which should be of special concern to hunters).  There are many, many questions at this point.

Excerpts from Elizabeth S. Williams et al. (2018) in the Journal of Wildlife Diseases: CATTLE (BOS TAURUS) RESIST CHRONIC WASTING DISEASE FOLLOWING ORAL INOCULATION CHALLENGE OR TEN YEARS' NATURAL EXPOSURE IN CONTAMINATED ENVIRONMENTS

Abstract: We conducted a 10-yr study to establish whether chronic wasting disease (CWD) was readily transmissible to domestic cattle (Bos taurus) following oral inoculation or by cohousing cattle with captive cervids in outdoor research facilities where CWD was enzootic.  ...continue reading "Chronic Wasting Disease Does Not Spread to Cattle and Humans"

Published on Leave a comment on Chronic Wasting Disease Is Spreading In the United States

If you're a hunter or eat wild-caught game (deer, elk, moose, reindeer), then you should be concerned with chronic wasting disease (CWD). Chronic wasting disease is an always-fatal prion disease similar to "mad-cow disease" (bovine spongiform encephalopathy) in cattle.

In chronic wasting disease there is a long incubation period, followed by the brain become progressively like a sponge - riddled with holes, along with deterioration in brain function, behavioral changes, and eventually death. A horrible slow death. There are no treatments or vaccines.

It turns out that chronic wasting disease is slowly spreading and infecting wild game across the United States (26 states) and 3 Canadian provinces. [Also detected in Finland, Norway, South Korea, and Sweden.] The concern is that this disease will jump to humans, especially in people who eat contaminated meat.

A research center monitoring the situation and publishing information and research on its site is CIDRAP (Center for Infectious Disease and Policy). Make sure to look at the Tweets (Twitter).

One scary thing about CWD is that once it gets into the soil, it stays there for years, and high heat, disinfectants, and radiation don't kill it. Yikes! Dr.Zabel at the Colorado State Univ. Prion Research Center suggested a few years ago that controlled burns (fires) of infected fields or areas could eliminate the prions left behind by infected animals (from animal mucus/saliva, urine, and feces, and decaying carcasses) on plants and soil.

An article with advice for how hunters can protect themselves, and a map of where CWD is found in the US.: 5 Ways Hunters Can Prevent Spreading Chronic Wasting Disease

The Centers for Disease Control and Prevention (CDC) has several chronic wasting disease pages, including prevention and transmission.

Here is some of what CIDRAP says on their site about CWD:

Chronic wasting disease (CWD) is a prion disease that affects several cervid species: deer, elk, reindeer, sika deer, and moose. CWD was first identified in 1967 in a captive mule deer living in a Colorado research facility. In 1981, CWD was detected for the first time in a wild cervid. Since these initial detections, CWD has been identified in 26 states and three Canadian provinces. It has also been detected in Finland, Norway, South Korea, and Sweden. ...continue reading "Chronic Wasting Disease Is Spreading In the United States"

Published on Leave a comment on Can A Person Get Chronic Wasting Disease From Eating Infected Meat?

The horrible disease called chronic wasting disease (CWD) is spreading among deer, moose, and elk throughout the US and Canada, and reindeer in Norway. This prion disease is similar to "mad cow disease" (bovine spongiform encephalopathy) in cattle, scrapie in sheep and goats, or Creutzfeldt-Jakob disease in humans.  In CWD the brains become progressively like sponges - riddled with holes, along with deterioration in brain function, behavioral changes, and eventually death. Especially worrisome is that it is an infectious disease.

The Centers for Disease Control (CDC) reported in January 2019 that chronic wasting disease has been reported in deer, moose, and elk across 26 US states and 3 Canadian provinces - in both free ranging herds and also some captive herds (such as in ranches and game farms). The following excerpts are from the  CDC site on Chronic Wasting Disease (CWD):

Chronic wasting disease (CWD) is a prion disease that affects deer, elk, reindeer, sika deer and moose. It has been found in some areas of North America, including Canada and the United States, Norway and South Korea. It may take over a year before an infected animal develops symptoms, which can include drastic weight loss (wasting), stumbling, listlessness and other neurologic symptoms. CWD can affect animals of all ages and some infected animals may die without ever developing the disease. CWD is fatal to animals and there are no treatments or vaccines.

To date, there have been no reported cases of CWD infection in people. However, animal studies suggest CWD poses a risk to some types of non-human primates, like monkeys, that eat meat from CWD-infected animals or come in contact with brain or body fluids from infected deer or elk. These studies raise concerns that there may also be a risk to people. Since 1997, the World Health Organization has recommended that it is important to keep the agents of all known prion diseases from entering the human food chain.  ...continue reading "Can A Person Get Chronic Wasting Disease From Eating Infected Meat?"