Deadly chronic wasting disease has Michigan's deer herd in its sights

Hunters are looking forward to the firearms deer season, but there's a soulless killer stalking the woods that has the state's deer herd in its sights, one that could jeopardize an activity generating an estimated $2.3 billion annually for the Michigan economy.

On Oct. 24, the Michigan Department of Natural Resources released a statement that a deer harvested in Sidney Township in Montcalm County was suspected positive for chronic wasting disease.

It would be the second deer in Montcalm County and the 11th harvested in an area in mid-Michigan that also includes Ingham and Clinton counties to have tested positive for the neurological disease that kills white-tailed and mule deer, elk and moose.

At stake, if CWD continues to make inroads into the state's deer herd, are not only businesses ranging from big box stores such as Cabela's in Chesterfield Township to early-morning breakfast cafes and mom-and-pop stores in places like Blaine and Ubly, but possibly human health.

A Canadian study released this year found the disease could be transmitted to macaques, a monkey genetically similar to people, by feeding the monkeys meat from deer that had tested positive for CWD.

"I hope it doesn't spread throughout the herd and you would have to worry about eating that type of meat," said Dave McInnis, a hunter from Port Huron Township. He took a six-point buck with a crossbow on Oct. 2.

Chronic wasting disease resurrects the specter of mad cow disease, according to Kelly Straka, DNR state wildlife veterinarian. Mad cow ravaged the cattle industry in the United Kingdom in the 1990s and into the 2000s and caused health scares in the United States and Canada.

According to data from the World Health Organization, 175 people in the United Kingdom were diagnosed from 1996 to 2011 with a neurological disorder called variant Creutzfeldt-Jakob Disease that is linked to consumption of meat from cattle with mad cow disease, also known as bovine spongiform encephalopathy. The peak was 28 deaths in the UK in 2000. It has declined since 2008 to two deaths and two diagnosed cases per year.

Researchers linked mad cow disease to the practice of feeding cattle protein from sheep infected with a disease called scrapie. That practice has since been banned.

"... Variant Creutzfeldt-Jakob Disease has been confirmed as being linked to mad cow disease," Straka said. "The same concern exists for chronic wasting disease. To date, there has been no human case of chronic wasting disease, unlike mad cow. It is a very active area of study."

While there have been no reported cases of CWD infecting humans, the Centers for Disease Control and Prevention aren't waiting for that to happen. The agency and the World Health Organization both recommend infected animals not be consumed by people or animals.

What is Chronic Wasting Disease?

Chronic wasting disease can be grouped with other degenerative disorders such as mad cow disease, scrapie, Creutzfeld-Jakob Disease and kuru that affect the brain and nervous systems of mammals.

The disorders are caused by infectious agents called prions.

"Prion is just a fancy word for a protein," Straka said. "It’s not a living organism."

Unlike other infectious agents, such as bacteria and viruses, prions do not contain nucleic acids. They punch lesions — microscopic holes — in the brain or other neural tissues, resulting in a spongy structure and a progressive degeneration of function that cannot be treated and is fatal.

While it was first detected in Michigan in 2008 — in a captive deer in Kent County — CWD has been a concern among wildlife scientists since it was first detected in 1967 at a research facility in Fort Collins, Colorado.

Straka said while CWD and scrapie are "technically two different diseases, one theory is CWD originated from scrapie. One of the concerns is, could scrapie have mutated along the way and turned into CWD?

"I don’t think that has been proven definitively."

In western states, such as Colorado and Wyoming, deer and elk typically share the range with sheep and cattle.

Chronic wasting disease was detected in Wisconsin in 2002 and, according to the CDC, has been detected in 181 counties in 21 states including Michigan. The DNR, Straka said, started doing surveillance for CWD in 2002

She said the disease can be transmitted via direct contact with an infected animal through saliva, feces and possibly blood. She said it also can be transmitted through indirect contact such as a deer nibbling on a food item that previously had been tasted by an infected animal.

"The issue we have with baiting, and the issue I have as a vet, is with any situation that artificially congregates animals," Straka said.

"Baiting is not a good practice when you’re dealing with trying to protect the health of animals."

She said it's the "Daycare 101" principle: Put a child in daycare, and that child will bring home a cold.

Straka said researchers do not yet know the minimum dose of the infectious prions needed to transmit the disease.

They also don't exactly know how it got to Michigan, she said. The infected deer in Michigan are in the middle of the Lower Peninsula, not along the Upper Peninsula border with Wisconsin.

"If you would go ahead and tell me the answer for that, it would be fantastic," Straka said. "We don’t know how it got to where we found it."

"... That’s one of the hardest things about this disease. Nothing about this is easy."

She said while Michigan is fortunate to have Lake Michigan as a barrier between most of the two states, "it is definitely a concern that we are so close to a state that has such a high prevalence of the disease.

"In certain areas of Wisconsin, they can have as high as 50 percent prevalence."

While researchers have not been able to find a reported case of CWD in humans, the occurrence of classic Creutzfeldt-Jakob Disease in the U.S. has risen from 179 in 1979 to 481 in 2015, according to data from the CDC.

No Easy Answers

Straka said reducing the deer herd isn't the easy fix.

"We are showing a lot of concerns in mule deer herds out West that are really low density," she said. "Having deer populations at lower densities isn’t necessarily the answer."

Not hunting is not an answer, she said.

"One of my big concerns is we are going to have people who are afraid to hunt and I don’t want to see that," Straka said. "My suggestion is getting your deer tested.

"... We make a strong recommendation that people do not consume a known positive."

Hunters can submit deer for testing at check stations throughout the state, she said. The nearest check stations are at the DNR's Cass City Field office, 4017 E. Caro Road; The Lapeer State Game Area, 3116 Vernor Road; and the Mount Clemens Fish Research Station, 33135 S. River Road, Harrison Township.

Chad Stewart, DNR deer specialist, said having deer tested "helps our surveillance and gives you a little more peace of mind."

To test or not to test, he said, depends on an individual's risk tolerance.

"I know people who will never have a CWD test because they don’t believe they have a CWD deer … and I know people who would never eat a deer unless it had a CWD test with it," he said.

"The test that we do at the lab is not considered a meat safety test. The test for CWD doesn’t tell you the animal is CWD-free. It means CWD was not detected."

The state since May 2015 has tested more than 15,000 deer. It also has created a five-county CWD management zone (DMU 419) and a 20-township core CWD area (DMU 333) within DMU 419. The state also created a nine-township core CWD area (DMU 359) within Mecosta and Montcalm counties (DMU 354) in response to two positive deer at a deer farm.

All the areas are in mid-Michigan. Baiting is banned in those areas, and all harvested deer must be registered at a check station within 72 hours of harvest.

The DNR recommends several precautions when field dressing deer in the CWD areas that hunters elsewhere can follow:

  • Wear rubber gloves when field dressing your deer.
  • Bone out the meat from your deer.
  • Minimize the handling of brain and spinal tissues.
  • Wash hands and instruments thoroughly after field dressing is completed.
  • Avoid consuming brain, spinal cord, eyes, spleen, tonsils and lymph nodes of harvested animals. (Normal field dressing coupled with boning out of a carcass will essentially remove all of these parts.)
  • Request that your animal is processed individually, without meat from other animals being added to meat from your animal.

The signs of CWD in deer are:

  • Loss of body condition or emaciation
  • Change in behavior such as loss of fear of humans
  • Loss of bodily control or movements
  • Excessive drooling and salivating

Deer Herd in Good Shape Heading into Opener

Another deer disease, epizootic hemorrhagic disease, has been reported in deer in St. Clair County, Stewart said.

It is a disease caused by a virus and is characterized by extensive bleeding, Unlike CWD, it is transmitted by biting flies. A deer must be bitten by a fly carrying the virus in order to be infected.

Stewart said he doesn't expect the outbreak to be crippling.

"Locally it could impact deer sightings," he said.

The midges stop biting after the first frost, which has happened.

"We should cease or start to see a noticeable decline in reports," Stewart said. "That basically shuts off the transmission of that disease because those flies can’t get past the frost.

"Anywhere you see sort of ponds or streams receding either due to high temperatures or lack of rainfall and you see those muddy banks that increases the chances of EHD," Stewart said. "Those muddy banks are breeding habitat for the flies."

Indications are the deer herd is in pretty good shape in St. Clair and Sanilac counties heading into the Nov. 15 opener.

"I've been out a few times," said Bob Jury, who hunts with a bow and a muzzleloader near Sandusky. "The last two times I was out, I saw maybe 60 deer.

"I've seen maybe nine bucks."

He said he holds out for bucks that have racks with at least eight points.

"I've seen a few that I would have shot if they had been closer," he said. "It's been phenomenal."

He said the farmer on whose land he hunts "told me the other day this is the biggest deer herd he's ever seen since he's been up there."

Stewart said the state expects about 600,000 hunters will purchase about 630,000 licenses of all types.

"There is no shortage of licenses available in most places, especially on private land," he said.

The state is forecasting the deer harvest will be similar to 2016 when hunters reported killing 348,222 deer, up 4.1 percent from 2015.

That total includes 164,843 killed during the regular firearms season, a decrease of 6 percent from 2015 as more and more hunters take advantage of archery and muzzleloader seasons.

Hunters in Deer Management Unit 74, St. Clair County, harvested 5,543 deer in 2016. Hunters in DMU 332, Sanilac, Huron and Tuscola counties, harvested 24,995 deer.

"Michigan has a pretty deep tradition in deer hunting," Stewart said. "There is a culture that is ingrained in this state with deer hunting, and you would hate to see any diminishment in that as well."

If you go

  • The Michigan firearms deer season is Nov. 15-30
  • Resident deer hunters need a base license, which also serves as a small game license. The cost is $11. Deer licenses with one kill tag are $20. A combo license with two kill tags is $40.
  • Archery-only continues through Nov. 14 and picks up again after firearms season from Dec. 1 to Jan. 1.
  • Muzzleloading season is Dec. 1-10 in the Upper and northern Lower Peninsulas and Dec. 1-17 in the southern Lower Peninsula.
  • Deer management units in St. Clair County and the Thumb are open for the late antlerless firearm season from Dec. 18 to Jan. 1. Click here for information about the antlerless deer hunt.
  • More information is available here.  

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© 2017, The Times Herald


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