Best Of Insight: Taylor's Market's Message on Mental Health and ...
What Is The 'Zombie' Disease Impacting The US's Deer Population
A horrific disease has been taking hold of deer across the US, leaving them debilitated by slowly shutting down their bodies.
The first case in Yellowstone National Park was recently discovered in an adult male mule deer, but cases of what is known as "zombie deer" disease have been recorded across the country since the 1960s.
But what is this disease, how does it work and should humans be concerned about it? Here is everything we know about this illness.
Chronic wasting disease, otherwise known as "zombie deer" disease, is part of a family of prion illnesses – where a type of protein folded in an obscure way can cause other proteins to fold in the same way, leading to cellular death, according to the Centers for Disease Control and Prevention (CDC).
These rare illnesses are known for their long incubation periods that eventually affect how the brain functions.
Versions of prion diseases can affect humans, but it's more typical among animals.
In this case, the Animal and Plant Inspection Service says chronic wasting disease has so far only been recorded as naturally occurring in deer, reindeer, moose and elk.
The CDC said the disease has been known to make deer lose weight drastically, stumble around, lose energy and other neurologic symptoms, but it may take over a year after contraction for this to develop.
There are currently no treatments or vaccines for this disease.
Sometimes, deer will die without ever developing the zombie-like symptoms.
Norway, Finland and Sweden and a small number of imported cases in South Korea have been recorded in reindeer and moose.
As of November 2023, there have been cases of chronic wasting disease in free-ranging deer, elk and moose in at least 31 states in the US, as well as three provinces in Canada, according to the CDC.
Yet this disease is not a new occurrence; the first identified case of chronic wasting disease was in captive deer in a Colorado research facility in the late 1960s, then in wild deer in 1981.
CWD has yet to be linked to humans, but the health department still advises to take extra precaution (Idir D/Getty Images)
By the 1990s, Colorado and Wyoming saw cases spreading, which has now spread further across the country. Other states without robust wildlife surveillance may be affected, but cases have not been confirmed.
The CDC expects the affected areas to continue to expand; in some of the most densely affected areas, infection rates may exceed one in 10 deer and elk.
In one captive deer herd, it is reported that the rates were much higher, four in five, which suggests a greater risk than wild deer.
Chronic wasting disease is thought to be spread between the animals directly or indirectly through bodily fluids such as faeces, saliva, blood, and urine, such as through the same food or water source. The disease is highly contagious and can spread quickly, especially within captive herds.
However, no known cases of chronic wasting disease have affected humans, according to the CDC, but initial studies are underway to determine if the disease can spread to human bodies.
Despite the lack of cases, scientists have been studying if prion diseases could be occurring at a higher rate in people who are in contact with or eat elk or deer meat, but due to the long incubation periods of the illness, it may be years before any risks are discovered.
Apart from humans, for animals not from the Cervid family (deer, moose and elk), experimental research has found that chronic wasting disease as infected squirrel monkeys and laboratory mice that carry some human genes, reports the CDC.
Testing was also carried out on macaques, a monkey that is the most genetically similar to humans out of any animal and was found to be infected by chronic wasting disease after being fed infected deer meat.
While little is known about chronic wasting disease and human exposure, the CDC has recommended that hunters should test meat they have caught from deer, especially in areas where chronic wasting disease is rife.
To be extra cautious, people are also advised to avoid sick-looking animals, wear protective gear and latex gloves when handling the animal or its meat, minimise the handling of organs, and not use household utensils while field dressing.
Q&A: How Chronic Wasting Disease Threatens Deer Populations
With the firearm deer hunting season kicking off, many Michigan hunters have their minds set to bring home a winning whitetail. But for Sonja Christensen, an assistant professor in the Department of Fisheries and Wildlife in Michigan State University's College of Agriculture and Natural Resources, the focus—now and all year long—is on protecting deer from disease.
Christensen's research focuses on why diseases occur and how those diseases influence wildlife populations. One example is chronic wasting disease, or CWD, a fatal condition that is now affecting cervid populations, including deer, elk and moose throughout Michigan and other states. Christensen answers questions on what you should know about CWD and what research she is leading to prevent its spread.
What is CWD and how does it work?Chronic wasting disease is a neurodegenerative condition caused by prions—an abnormal form of protein. It is not known to affect humans, but CWD is fatal in all cases involving cervids, or mammals that have solid deciduous antlers.
Transmission is thought to be caused by direct or indirect contact with infectious prions in bodily fluids like urine, feces or saliva. Studies show that prions can persist in the environment for years, meaning current exposure risks in a given area may stem from the presence of infected deer from long ago. Symptoms of CWD can take months or years to emerge and may include rapid weight loss, disorientation and fatigue, among others.
How many deer have died as a result of contracting CWD, and should we be concerned about a dwindling deer population?Measuring how many wild deer are infected with a disease is a tremendous challenge. In fact, we do not have an exact number of how many free-ranging deer live in Michigan! Through surveillance work with the Michigan Department of Natural Resources, we know that CWD has been detected in 251 white-tailed deer since 2015. While that might not seem like a lot, it takes enormous effort to find sick deer, and there are likely more positive deer on the landscape that go undetected.
Research has shown that in cervid populations with a high prevalence of CWD, long-term population declines can occur. While deer are overabundant in many places in southern Michigan, they are a valuable native wildlife species, and we want to ensure they are healthy. White-tailed deer play a huge role in our ecosystems, culture> and Michigan economy.
Further, deer hunting license sales and excise taxes from firearms and ammunition generate funding that go directly to wildlife management and conservation for many more of our native species.
Should hunters be concerned about deer with CWD?While CWD has never been conclusively detected in a human, my rule of thumb is that if it looks sick and you are concerned, do not eat it. Past research indicates some barrier exists between transmission of CWD from deer to humans, but more research is needed on this front.
I recommend checking out the Michigan DNR's current guidelines on testing for the best available options. Also, if you see a deer that appears sick, please report it to the MDNR. Finding a newly infected deer can be like finding a needle in a haystack, and we need all the eyes and ears we can get!
Where has CWD been detected, and is it a problem in Michigan?CWD was first discovered in 1967 in Colorado and, according to the U.S. Geological Survey, it has been found in at least 31 states and four Canadian provinces. CWD also has been detected in a small number of European countries and in imported deer in South Korea.
The first CWD case in Michigan was discovered in 2008 in a captive whitetail and next in 2015 in a free-ranging deer. Since then, the disease has emerged in both the lower and upper peninsulas, but according to the MDNR, no new counties saw positive cases in 2022 sampling.
What findings have you made regarding the disease?In a study published in the Journal of Wildlife Management in August 2022, my colleague and I found one of the complicating factors in managing CWD is the complex nature of white-tailed deer ecology. The persistence of prions in the environment, long-range deer movement and interactions with humans, such as the transportation of CWD-positive carcasses, are all unpredictable factors that our team's models were designed to account for.
Further, I collaborate closely with colleagues from Cornell University on a project called SOP4CWD, which focuses on CWD surveillance and risk across states, to better understand how disease risks may differ in various regions of the United States. These efforts are all focused on finding the disease early so that state wildlife agencies have a chance at stopping its spread.
The Wildlife Society held a meeting in November where I presented research that a colleague and I conducted evaluating how other diseases—such as epizootic hemorrhagic disease, or EHD—interact with CWD to affect deer. We found that localized EHD outbreaks may actually help reduce CWD and provide a small silver lining in places where CWD has very recently emerged.
Much of my current work focuses on understanding and changing human behavior to help reduce risk factors for CWD in deer and to assist with disease management efforts. This might be in the form of finding incentives for helping hunters reduce the spread of disease from harvested deer or through cooperating with landowners to tackle disease management on private lands.
How can CWD be mitigated?Our best chance to stop or slow disease spread is to prevent activities that we know are risky for CWD transmission, identify instances of disease early and give management agencies the upper hand in making proactive recommendations rather than reacting to disease outbreaks.
For a project published in the Wildlife Society Bulletin in March 2023, my colleague and I, as well as researchers from Mississippi State University, characterized management agencies' CWD efforts in the U.S., Canada and Europe. Researchers reported the effects of management at various stages before and after detection.
Twelve of the 24 responding agencies had a weighted surveillance program in place, which puts a greater emphasis on deer with heightened risk factors. Initial responses to CWD detection included bans on movement of live or dead animals and increased bag limits.
We found that of the roughly 20 U.S. States and six Canadian provinces that have not found CWD, only three had active weighted surveillance programs in place. Just four of these states and two provinces had a response plan available online. Therefore, we recommended agencies be proactive in response plan development and to communicate with the public and other stakeholders on disease progression and management outcomes. Prevention is priceless.
What other disease-based research do you conduct?My research program is aimed at understanding how and why diseases occur, and how that affects wildlife populations. As I mentioned, deer diseases of interest to me include epizootic hemorrhagic disease—a viral illness transmitted by biting midges—and blue tongue disease, a similar ailment.
SARS-CoV-2, the virus that causes COVID-19, has come up as well as deer have been affected. Research is needed to determine if there are spillover effects with humans. Many diseases continue to challenge wildlife populations in Michigan, and I will continue to work on understanding how these diseases affect populations of cervids and, hopefully, reduce the threats.
More information: Noelle E. Thompson et al, Wildlife agency responses to chronic wasting disease in free‐ranging cervids, Wildlife Society Bulletin (2023). DOI: 10.1002/wsb.1435
Citation: Q&A: How chronic wasting disease threatens deer populations (2023, November 17) retrieved 30 November 2023 from https://phys.Org/news/2023-11-qa-chronic-disease-threatens-deer.Html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
First-ever Known Case Of 'ZOMBIE' Deer Disease Confirmed In Yellowstone National Park: Officials Warn Of Fatal Brain Virus That Makes Animals Drool And Unafraid Of Humans
The first case of 'zombie' deer disease has been reported in Yellowstone National Park after a deer carcass tested positive for chronic wasting disease (CWD).
The fatal brain virus leaves animals confused, drooling and uncoordinated, reducing their fear of humans.
The US National Park Service has warned patrons to report any sightings of sick or dead wildlife 'as soon as possible' and to 'avoid contact with the animal' as their staff races to prevent further brain disease spread.
In recent years, CWD has spread to over 23 US states, two Canadian provinces and even South Korea, according to the US Geological Survey.
Chronic wasting disease (CWD) is a prion-transmitted disease, similar to 'Mad Cow,' which can cause weight loss, loss of coordination and other eventually fatal neurological symptoms in deer. Above, a deer killed by CWD as identified by Mississippi wildlife officials
Chronic wasting disease (CWD) results in 'zombie-like' symptoms that leave creatures confused, drooling and uncoordinated - without fear of humans. CWD has spread to over 23 US states, two Canadian provinces and South Korea, according to the US Geological Survey
'There is currently no evidence that CWD can infect humans or domestic animal species,' the US National Park Service advised in its statement announcing the discovery of the dead mule buck.
'However,' the federal agency cautioned game hunters in particular, 'it is recommended that tissues from CWD-infected animals not be consumed.'
Samples from the body of the infected mule deer tested positive for CWD over multiple rounds conducted by the Wyoming Game and Fish Department's (WGFD) Wildlife Health Laboratory.
Typical testing of live and dead animals involves sampling a creature's nervous system tissue, either from the central nervous system, like the spinal cord, or peripheral systems, like the retropharyngeal lymph nodes and the tonsils.
CWD is a prion-transmitted disease, similar to 'Mad Cow,' which can cause weight loss, loss of coordination and other eventually fatal neurological symptoms in deer and related species.
'Prion diseases,' according to Johns Hopkins Medicine, 'occur when normal prion protein, found on the surface of many cells, becomes abnormal and clump in the brain, causing brain damage.'
There is currently no vaccine or cure for CWD, authorities said, and the disease is 100 percent fatal.
The US National Park Service (NPS) has issued a warning to park patrons to report any sightings of sick or dead wildlife 'as soon as possible' and to 'avoid contact with the animal' as their staff races to prevent the further spread of the brain disease across Yellowstone
Wildlife managers working for the state of Wyoming and Yellowstone National Park have positively confirmed that an adult mule deer buck has died of the fatal brain disease — the first ever known case of CWD within Yellowstone's boundaries
The infected buck's corpse was tracked down to a peninsula along Yellowstone Lake's southern edge, via a GPS collar outfitted last March for a population dynamics study
Park officials at Yellowstone said they are now working with WGFD to monitor the park's deer and other hooved species, both dead and alive, to assess better how far CWD has spread through the national park.
Yellowstone National Park officials said that the discovery has prompted them to revise the park's 2021 CWD surveillance plan — with a new protocol version expected sometime next year.
Park spokesperson Morgan Warthin said Yellowstone also plans to increase its collaborative efforts with WGFD to identify which areas of the park are at increased risk from the disease.
CWD was first detected in mule deer in Wyoming in 1985 along the state's southeastern region.
The following year, the fatal brain disease was discovered in Wyoming elk, according to WGFD.
The disease's arrival in Yellowstone marks the end of a decades-long spread westward across the state, reaching the national park's location in Wyoming's northwest corner.
Wyoming game officials had been tracking the mule deer buck from March 2023 until October 2023, when its GPS tag indicated it had likely died.
Their search for its body took them to a landmass between the south and southeastern arms of Yellowstone Lake, known as the Promontory.
North of the park, Montana state wildlife regulators are also assisting in the effort and monitoring game caught by their state's local hunters.
A spokesperson for Region 3 of Montana Fish, Wildlife & Parks, Morgan Jacobsen, told the Daily Montanan that many CWD cases have not yet been detected in the state's hunting districts bordering Yellowstone.
Jacobsen described the news as a 'data point of interest,' but not one that would radically change Montana's own CWD surveillance plans.
'We're going to continue our monitoring and communication with the park and continue to work with hunters as the primary management tool for CWD in Montana,' Jacobsen said.
Comments
Post a Comment