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Iowa DNR places deer disease surveillance priority on Woodbury County December 4, 2019

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Iowa DNR places deer disease surveillance priority on Woodbury County

December 3, 2019 Iowa DNR News

Sioux City, Iowa - A tissue sample from a road killed deer collected on the south side of Sioux City is undergoing a follow up test for chronic wasting disease after its initial results showed a high likelihood that the disease was present. If confirmed, Woodbury County would become the fifth Iowa county where a wild deer has tested positive for the always fatal disease.

“We are going forward with our surveillance plan based on the presumption that the follow-up test will be positive,” said Todd Bishop, chief of the Iowa Department of Natural Resources (DNR) Wildlife Bureau.

The Iowa DNR has established a priority zone for tissue collection in Woodbury County extending 10 miles around where the positive sample was collected and is working to have a map available online at Hunters who harvest a deer in the priority zone or outside the zone in western Woodbury County are encouraged to contact the DNR at 712-420-5584 to arrange for sample collection.

“We will be looking to collect additional samples from hunter harvested and road killed deer but, at this point, we are not planning to increase the number of deer harvested in the area as the local herd density is at or below our population goals,” Bishop said.

Chronic wasting disease was first confirmed in wild deer in Iowa in Allamakee County in 2013. It has since been found in Clayton, Dubuque and Wayne counties. In addition to the presumptive positive in Woodbury County, the Iowa DNR has confirmed positive samples from deer in Allamakee and Wayne counties so far during the 2019 testing season.

“We’re fortunate to have a solid partner in Sioux City who’s been managing deer hunting within city limits and we’re planning for that partnership to continue,” Bishop said. “We’d also like to reach out to other hunters in the area who harvest a deer in the priority area or in western Woodbury County, to encourage them to provide tissue samples.”

Chronic wasting disease was first confirmed in the Midwest in Wisconsin in 2001 about 75 miles from the Iowa state line, and has since been confirmed in every other state bordering Iowa. It is a neurological disease belonging to the family of diseases known as transmissible spongiform encephalopathies (TSEs) or prion diseases. It attacks the brain of infected deer causing the animal to lose weight, display abnormal behavior, lose body functions and die. It is always fatal to the infected animal.

The Iowa DNR began monitoring for the disease in 2002 with an emphasis on counties nearest where it was confirmed in the wild and has tested more than 74,000 deer since. There are a few things hunters can do to stop or slow the spread of chronic wasting disease, including not leaving the deer carcass on the landscape and not using feed or salt-mineral to attract deer. Sioux City banned feeding deer within city limits in 2012.


Sidebar: Chronic Wasting Disease Background

What is Chronic Wasting Disease (CWD)?

CWD is a neurological disease affecting primarily deer and elk. An abnormal protein, called a prion, affects the brains of infected animals causing them to lose weight, display abnormal behavior and lose bodily functions. Signs of CWD in deer include excessive salivation, thirst and urination, loss of appetite, weight loss, listlessness and drooping ears and head. It is always fatal to the infected animal. Anyone seeing a deer exhibiting these symptoms should immediately contact the DNR. CWD is a slowly progressive disease; signs are usually not seen until the animal is 18 months of age or older. Nearly all of the deer that tested positive in Iowa so far have appeared to be healthy and did not exhibit any signs of the disease.


How is CWD diagnosed?

Lymph nodes and brain samples are collected from hunter‐harvested or dead deer and sent to nationally certified labs where they are examined microscopically using special stains to identify CWD prions.


How is CWD transmitted?

CWD can be transferred from deer to deer via direct contact and contact with bodily fluids. Therefore, prevalence and spread increase with deer density. However, abnormal protein prions that are shed from CWD positive deer can persist in the environment for many years, which can additionally infect deer. As a result, disease prevalence is also independent of deer density. There is currently no viable vaccine. Consequently, once a wild deer herd has become infected, removal is nearly impossible and increased prevalence is extremely likely. Deer management strategies generally have focused on mitigating the prevalence and spread of the disease via population reduction or some form of isolating or quarantining infected areas. Recent research in Wyoming has found that CWD has been documented to have strong population-level effects.


Is CWD a risk for Iowa’s livestock?

There is no evidence that CWD can be transmitted under natural conditions to cattle. Scientists have attempted to transmit CWD to cattle by injecting CWD infected material directly into the brain, but the cattle did not develop signs of disease.


If my deer is tested, how do I get my results?

The Iowa DNR has launched a new online system where hunters who provide samples for chronic wasting disease testing can check on the test results themselves. Go to and click on the CWD reporting system link on the right. There, they can enter either their hunter identification number or the nine digit registration number on the deer tag. Results should be available in 2-3 weeks. Hunters who are awaiting the testing results are encouraged to keep that deer separate from others and hold off on processing in the event that it tests positive. 


What do the test results mean?

Testing for the CWD protein is not a food safety test. Currently there are no known cases of humans contracting CWD by eating venison; however, the Center for Disease Control and Prevention recommends, when hunting in areas with CWD, strongly consider having the deer tested for CWD before you eat the meat. If your animal tests positive for CWD, do not eat that animal. For further recommendations, refer to information provided by the Centers for Disease Control and Prevention.


What do I do if the results are positive?

Staff from the Iowa DNR will contact hunters who have a positive deer. If the hunter no longer wants the meat, the DNR will collect it and the hide and bones.


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