Chronic Wasting Disease: It’s a Big Problem
Chronic Wasting Disease, also known as CWD, is a disease that was found initially in a captive deer herd in the 1960s in Colorado (Chronic Wasting Disease (CWD) | Prion Diseases | CDC, 2021). Chronic Wasting Disease affects animals classified as cervids, also known as the deer family. These animals include all species of deer, including reindeer, elk, and even moose. This disease is easily spread through the cervid population and is always fatal. Chronic Wasting Disease can wreak havoc on the animal population not only in the United States but across the world. While the cause of the disease may be unknown, and it affects only species of cervids, the effects of this disease can be felt in the local economies as well.
Chronic Wasting Disease is a neurological disease that affects all members of the deer family. Like mad cow disease in cattle, Chronic Wasting Disease is not caused by a virus or bacteria, but rather by abnormal prions or proteins (PGC, n.d.). While this disease is highly transmittable through the deer populations, it has not been proven that it is transmittable to cattle, other domesticated animals, or humans (Chronic Wasting Disease (CWD) | Prion Diseases | CDC, 2021). Chronic Wasting Disease is an always fatal disease that affects the brain, spinal cord, and other tissues of both farm-raised and free-ranging deer, elk, and moose. Scientists believe this disease is spread through contact with contaminated body fluids, such as saliva, urine, and feces. Chronic Wasting Disease is also believed to be indirectly spread through contaminated environments (PGC, n.d.). This disease is not just limited to the United States. Chronic Wasting Disease has also been found in Canada, Norway, Finland, and South Korea.
In the United States, 25 states have known cases of Chronic Wasting Disease in either captive or wild deer. Those states that have been known to possess deer with Chronic Wasting Disease are: Colorado, Wyoming, South Dakota, Nebraska, Montana, Wisconsin, New Mexico, Minnesota, Oklahoma, Illinois, Utah, New York, West Virginia, Kansas, Michigan, Virginia, Missouri, North Dakota, Maryland, Iowa, Pennsylvania, Ohio, Mississippi, Texas, and Arkansas (Texas Parks and Wildlife Department, 2018). While the exact source of Chronic Wasting Disease may not ever be known, scientists do know quite a lot about this disease.
Nationwide, occurrences in free-ranging cervids are relatively low. However, in locations where the disease is established, infection rates may exceed 10 percent with localized rates of 25 percent or greater. In captive deer, the rate of infection drastically increased to nearly 79 percent of the herd (Chronic Wasting Disease (CWD) | Prion Diseases | CDC, 2021). Similar to other prion diseases, Chronic Wasting Disease is believed to have a long period of incubation. While the exact incubation time is unknown because actual exposure time cannot be determined in free-range settings, scientists have performed experiments and have determined the minimum incubation time for the disease is 15 months. The average time from oral infection in clinical settings to death was around 23 months (Alliance, n.d.-a). Signs of infection can develop slowly and may even take a year to visually affect the animal. As the disease progresses in the infected animal, the animals begin to show signs of Chronic Wasting Disease. These signs can be a change in the behavior and the appearance of the animal. Some of these signs include drastic weight loss, stumbling, lack of coordination, drooling, excessive thirst or urination, dropping ears, and even a lack of fear of people (Chronic Wasting Disease (CWD) | Prion Diseases | CDC, 2021). However, it may be difficult to determine without scientific testing if the deer, elk, or moose have Chronic Wasting Disease because these symptoms can also occur with other diseases or can be a sign of poor nutrition. Currently, there are no vaccines capable of preventing infection (Alliance, n.d.-a). While the disease may not be able to be transmitted to humans, the effect of the disease can cause problems to the local economies of areas where the infection is prevalent.
Chronic Wasting Disease can play a major role in the decline of some local economies. For some portions of the United States, commercial deer farms and hunting are large sources of income. Income generated through hunting often includes license fees, lodging, and purchase of equipment These purchases can generate a large amount of spending for the area, and in 2016 it was reported the average person spent $1,619 that year on hunting-related purchases (Olexa, Caracciolo, Fernandez, Owen, 2021). Besides the money generated through recreational hunting, commercial deer farming is another large source of income. Commercial deer farms generate revenue through the sale of live animals, antlers, meat, urine, and semen. In the 2017 Census of Agriculture, they reported sales in Florida from deer farms totaled $1,087,000 in 2012 (Olexa et al, 2021). Due to the large number of funds generated from these two types of activities, any new introduction or increase in Chronic Wasting Disease cases can have a large impact on the local economies. With an outbreak of Chronic Wasting Disease, deer farms will lose their source of income, and recreational hunting will not be as popular in these areas. A study on the impact of Chronic Wasting Disease was performed in Wisconsin, and it was reported that the economic impact was estimated to be between $53 million and $79 million in 2002 (Bishop, 2004). In Texas, hunting generates an average of $2.2 billion and supports many rural towns across the state (Texas Parks and Wildlife Department, 2018). If a large outbreak of Chronic Wasting Disease would occur here, the local economy would decrease significantly and the towns that depend on the money would suffer.
Chronic Wasting Disease is a serious problem in many regions around the world. With no cure or way to stop the disease, we can only hope to minimize the spread. If allowed to grow unchecked, not only will the deer, elk, and moose herd be in jeopardy, the economy will be impacted as well. By understanding how the disease is spread, we can institute control strategies that will help lessen the impact the disease will have in the future. Many states and local agencies are working to develop plans and strategies to protect their resources from the spread of Chronic Wasting Disease, and with any luck, we can stop the spread of this deadly disease.
-Adam Sites, Fall Obsession Pro Staff
References
Alliance, C. (n.d.-a). Chronic Wasting Disease FAQ. CWD-INFO.ORG. https://cwd-info.org/faq/
Bishop, R. C. (2004). The Economic Impacts of Chronic Wasting Disease (CWD) in Wisconsin. Human Dimensions of Wildlife, 9(3), 181–192. https://doi.org/10.1080/10871200490479963
Chronic Wasting Disease (CWD) | Prion Diseases | CDC. (2021, October 9). CDC. https://www.cdc.gov/prions/cwd/index.html
Olexa, M. T., Caracciolo, J., Fernandez, V., & Owen, S. (2021). Hanging on for Deer Life: How Chronic Wasting Disease Might Impact Florida and How Florida Law is Trying to Prevent its Spread into the State. Florida Bar Journal, 95(6), 44–47. PGC. (n.d.). Chronic Wasting Disease. Pennsylvania Game Commission. https://www.pgc.pa.gov/Wildlife/Wildlife-RelatedDiseases/Pages/ChronicWastingDisease.aspx
Texas Parks and Wildlife Department. Chronic Wasting Disease Fact Sheet. (2018, October). https://tpwd.texas.gov/documents/262/CWD-fact-sheet-pwd_lf_w7000_0859b.pdf