Beware Chronic Wasting Disease in white-tailed deer
Chronic wasting disease (CWD) and epizootic hemorrhagic disease (EHD) are the two most serious diseases affecting white-tailed deer, and the most commonly confused for one another. It’s important to know the difference, as there is no concern about eating a deer with EHD, but some concern does exist about the safety of handling, processing, and eating a deer with CWD.
Chronic Wasting Disease
Chronic Wasting Disease (CWD) is a fatal brain and nervous system disease affecting deer, elk, and moose. It was found in N.Y.S. in Oneida County in 2005 but hasn’t been detected since. Deer infected with CWD show the presence of abnormally shaped proteins called “prions,” which cause healthy proteins to convert into diseased proteins. Prions accumulate in tissues of the spinal cord, brain, eyes, spleen, tonsils, lymph nodes, and intestines. CWD prions are also found in saliva, urine, and feces of infested animals, allowing them to spread to healthy deer, elk, or moose that come in contact with contaminated bodily fluids or by eating contaminated food or water. Prions also bind to soil particles and remain viable in the environment for up to 18 years or more, potentially infecting many future generations of deer, elk, or moose.
CWD infected animals do not always appear sick. The disease attacks the brain and nervous system slowly, taking several months to years before the animal shows signs of infection, such as disorientation, extreme thirst, emaciation, loss of bodily functions, and ultimately; death. The Centers for Disease Control (CDC) urges caution when handling the meat of a potential or suspect CWD infected deer and recommends having the meat tested before consumption. For information about testing, visit the Cornell University Wildlife Health Lab: https://cwhl.vet.cornell.edu/hunter-cwd-testing
To help prevent CWD from arriving in N.Y. again, the N.Y.S. Department of Environmental Conservation (DEC) has implemented a CWD surveillance program to rapidly identify and prevent the spread of CWD in N.Y., focusing on animals and locations of greatest risk. Additionally, DEC and the N.Y.S. Department of Agriculture and Markets (DAM) have developed strategies and regulations to reduce the risk of CWD entry and spread in N.Y.S. from other parts of the country, such as not being permitted to bring hunter-killed deer, elk, moose, or caribou carcasses into N.Y. and annually DEC collects approximately 2,000 samples of brain tissue and lymph nodes from hunter-killed white-tailed deer and submits them for testing.
Also, when it comes to CWD and in general, feeding deer and other wildlife is generally discouraged, and increases the risk that CWD and other harmful diseases will spread. For more information about CWD and regulations and practices to help prevent its spread, visit N.Y.S. DEC’s website: https://www.dec.ny.gov/animals/7191.html
Epizootic Hemorrhagic Disease
Epizootic Hemorrhagic Disease (EHD) or often referred to as hemorrhagic disease (HD) or bluetongue virus (BT), are viruses spread by biting midges. EHD and BT are actually two very closely related viruses that cause HD in white-tailed deer, and HD is one of the most common diseases of white-tailed deer in the eastern U.S., causing a significant number of deaths during an outbreak. White-tailed deer and mule deer are the predominant wildlife species affected by HD, but it has been associated with the death of pronghorn antelope and bighorn sheep, and although not as susceptible, elk can contract HD. EHD can, but rarely causes, disease in domestic animals. BT can infect cattle, sheep, goats, and domestic dogs. EHD and BT viruses are found worldwide, but the only reports in wildlife have been in North America. In the U.S., HD has been confirmed in most eastern and southeastern states and several Midwest and northwest states. In N.Y., EHD was first confirmed in 2007 in Albany, Rensselaer, and Niagara Counties, and Rockland County in 2011. Most recently, EHD was detected in white-tailed deer in September 2020, in Putnam and Orange Counties.
EHD outbreaks most commonly occur in late summer and early fall when midges are abundant, and more often during drought and extreme heat conditions. An infected deer may display symptoms such as swelling of the head, neck, tongue, and lips and hemorrhages in muscle or organs causing visible symptoms like ulcers in the mouth and tongue and excessive blood-tinged saliva and nasal discharge. EHD infected deer may appear lame, disoriented, or dehydrated and will seek out water and often succumb near a water source. Infected deer do not spread the disease to each other. Overall, EHD outbreaks do not have significant, long-term impacts on deer populations. In the northeast, outbreaks of EHD occur sporadically and deer have not developed any immunity to the virus, so most deer infected with EHD in N.Y. will die from the disease.
Although EHD cannot be spread to humans, it can be hard to discern EHD from CWD, and since there is some concern about the handling and consumption of CWD infected deer, as a precautionary measure, DEC advises that hunters should not handle or eat any deer that appears sick or acts strangely. For more information about EHD, visit the Cornell Wildlife Health Lab’s website https://cwhl.vet.cornell.edu/article/epizootic-hemorrhagic-disease-white-tailed-deer. Sightings of sick or dying deer should be reported to DEC’s Wildlife Bureau firstname.lastname@example.org