Illinois and Chronic Wasting Disease (CWD)
Land ecology and its effects on the prevalence of Chronic Wasting Disease in Illinois deer populations.
CWD
Chronic Wasting Disease Among Free-Ranging Cervids by County, United States, August 2021 URL: https://www.cdc.gov/prions/cwd/images/cwd-map.jpg?_=24416
CWD has been detected in 26 US states and 3 Canadian provinces as of July 2020 (USGS, 2020). So far 19 counties in Illinois have reported CWD: Boone, Carroll, Cook, Dekalb, DuPage, Grundy, Jo Daviess, Kane, Kankakee, Kendall, Lake, LaSalle, Lee, Livingston, McHenry, Ogle, Stephenson, Will, and Winnebago (Map 1). All listed Illinois counties can be found in the northern part of the state, no reports have been found in Sangamon County or central and southern Illinois (CDC, 2021). There are counties in Missouri with CWD, but it is possible the Mississippi River creates a natural barrier preventing the spread of CWD into southern Illinois (CDC, 2021).
Map1. Map of Illinois counties with CWD.
Land Ecology and Usage
Illinois ranks third nationally in the export of agricultural commodities with $8.2 billion worth of goods shipped to other countries. (Illinois Department of Agriculture)
Project
Goal: Determine the landscape ecology of Illinois where CWD is present.
Results
Map 2 shows that there are three distinct areas where the frequency of CWD is great. The third area south of the two northern areas has lowest frequency of three but is possibly an area of interest for future analysis.
Map 2. The basemap with state boundary and county borders where CWD is present.
Map 3 shows the Cropland 2020 layer applied for the state of Illinois with the same heat map data used in Map 2. To show CWD data point location with landcover data.
Map 3. The Cropland 2020 layer with state boundary, county borders where CWD is present, and streams/rivers.
Map 4. The Cropland layer with state boundary and county borders where CWD is present with Cropland legend. Majority of the state is Corn (yellow) and Soybeans (pink).
Figure 2 displays the overall landcover area for the CWD data points from Map 3. Deciduous forest was the highest landcover area for CWD data, while corn was the second highest. Deciduous forest can be found in every county throughout the state of Illinois (Illinois DNR, n.d.).
Figure 2. Type of landcover CWD positive deer data points were located.
Conclusion
There were more male deer positive for CWD collected than female. Hunting was the most common death among the CWD positive deer collected (Figure 1). CWD appears to be related to the landscape ecology, with a high proportion of the CWD positive cases in deer being located within deciduous forest (Figure 2). Also, a high proportion was found within corn as well. Corn is in higher abundance of landcover than deciduous forest within the state of Illinois. Deciduous forests and corn tend to be preferred environments for hunters to station during the hunting season. Developed areas that are open space and have low intensity had similar amounts of data (Figure 2). Developed areas that are open space and have low intensity are rural areas, such as small towns or communities within Illinois with low density of people.
From a visual comparison, it appears there may be some association with CWD positive deer and streams/rivers this can be used in future research to consider. A limitation was not having an exact location of where the deer was found, location data was an estimate centralized within Township/Range/Section; therefore, the landscape where the point is within may not be accurate if more than one landscape is within the area.
Hunting has the risk of increased exposure of zoonotic CWD to human populations, over time frequent exposure could give opportunity for the disease to adapt to be transmissible to humans causing CWD cases within humans. Northern Illinois landscape is not very different from central or southern Illinois landscape. Over time majority of areas with corn and deciduous forest may experiences cases of CWD within the deer populations. Corn has a high prevalence throughout the stat. Deciduous forest are mainly located by streams/rivers, areas not touched by agriculture thus creating wildlife corridors for deer to travel. In conclusion, CWD will be found in central and southern Illinois deer populations over time.
References
Center for Disease Control and Prevention (CDC). (2019). Chronic Wasting Disease. URL: https://www.cdc.gov/prions/cwd/index.html
Center for Disease Control and Prevention (CDC). (2021). Chronic Wasting Disease: Occurrence. URL: https://www.cdc.gov/prions/cwd/occurrence.html
Department of Natural Resources (DNR) (Cartographer). (2004). Illinois Land Cover [map]. URL: https://files.isgs.illinois.edu/sites/default/files/maps/statewide/imap12.pdf
Illinois Department of Agriculture (IDOA). (n.d.). Facts About Illinois Agriculture. URL: https://www2.illinois.gov/sites/agr/About/Pages/Facts-About-Illinois-Agriculture.aspx#:~:text=Illinois%20farmland%20covers%2027%20million%20acres%20--%20about,about%20what%20it%20means%20to%20farm%20in%20Illinois.
Illinois Department of Natural Resources (IDNR). (n.d.) Upland Deciduous Forest. URL: https://www2.illinois.gov/dnr/education/Pages/CDHabitatUplandDeciduousForest.aspx#:~:text=In%20Illinois%2C%20there%20are%20nearly%203.6%20million%20acres,forests%20may%20be%20found%20in%20all%20Illinois%20counties.
Illinois Department of Natural Resources (IDNR). (n.d.). Getting Started-Hunting. URL: https://www2.illinois.gov/dnr/hunting/Pages/GettingStarted.aspx
McGarigal, Kevin. (n.d.). Introduction to Landscape Ecology. URL: https://www.umass.edu/landeco/about/landeco.pdf
United States Department of Agriculture (USDA). (n.d.). National Agricultural Statistics Service: Census of Agriculture. URL: https://www.nass.usda.gov/Publications/AgCensus/2017/Full_Report/Volume_1,_Chapter_1_State_Level/Illinois/st17_1_0007_0008.pdf
United States Geological Survey (USGS). (December 28, 2020). Chronic Wasting Disease: Can Science Save Our Dear Deer?. URL: https://www.usgs.gov/news/chronic-wasting-disease-can-science-save-our-dear-deer?qt-news_science_products=1#qt-news_science_products
Data Sources
Compiled CWD-POSITIVES 2002-2021 (2021) [excel file]. Daniel J. Skinner, Forest Wildlife Program Manager, Illinois Department of Natural Resources. [November 17, 2021]
Illinois County Boundaries (2003) [downloaded file]. Illinois State Geological Survey, Champaign, Illinois. URL: http://www.isgs.illinois.edu/ [November 2021]
USA Rivers and Streams (2014) [Feature Layer]. Esri on ArcGIS Online. URL: https://www.arcgis.com/home/item.html?id=0baca6c9ffd6499fb8e5fad50174c4e0 [November 2021]
U.S. States (Generalized) (2013) [Feature layer]. Esri on ArcGIS Online. URL: https://www.arcgis.com/home/item.html?id=99fd67933e754a1181cc755146be21ca [November 2021]
2020 Illinois Cropland Data Layer | NASS/USDA (2021) [downloaded file]. United States Department of Agriculture (USDA), National Agricultural Statistics Service (NASS), USDA, NASS Marketing and Information Services Office, Washington, D.C. URL: https://nassgeodata.gmu.edu/CropScape/ [November 2021]
