Chronic Wasting Disease
Chronic Wasting Disease (CWD), a fatal disease seen in deer, elk and moose, was first recognized in a captive mule deer found in 1967 in a Colorado research herd. CWD is related to scrapie in sheep, “mad cow” in cattle, and Creutzfeldt-Jakob disease in humans, and arises from misfolded prions in the brain, spinal cord, eyes, spleen and lymph nodes that attack the host’s nervous system.
Since its original discovery, CWD has spread widely, carried by saliva, urine, feces, and even contaminated soil. The accompanying map shows its range expansion over the 2000-2016 period. By December of 2016, CWD had been reported in 2 Canadian provinces and 24 states, including Texas.
Concerns about CWD’s arrival in Texas have been high. Herds are big: 4 million wild whitetail deer are estimated to live in the state, in addition to 110,000 or more pen-raised whitetails. Deer hunting is big business in the state: worth $2.2 billion per year, and especially valuable for small towns and rural landowners (hunting income trumps agricultural revenue for many).
To slow CWD’s spread, Texas Parks & Wildlife started testing some roadkill and hunters’ trophies for the disease in 2002, and by 2005, began blocking importation of out-of-state deer. Nevertheless, in 2012, biologists reported a free-ranging mule deer to be the first case of CWD known to Texas, and in 2017, a hunter brought in the first wild whitetail deer found to be carrying CWD in Texas.
Sources:
Eaton, Tim. 2016. “Texas Parks & Wildlife Tightens Rules on Deer Breeders”, in Austin American-Statesman. June 20, 2016.
Hancock, Lee. 2012. “The Bucks Stop Here”, in Texas Monthly. January 2012.
Hargrove, Brantley. 2016. “Chronic Wasting Unease”, in Texas Monthly. January 2016.
Richards, Bryan. 2017. Emerging Disease Coordinator, U.S. Geological Survey National Wildlife Health Center. Personal communications, May and June 2017.
Tomecek, John, Terry Hensley, Walt Cook, Bob Dittmar. 2015. A Guide to Chronic Wasting Disease (CWD) in Texas Cervids. Texas Agricultural Extension Service.