Origins
The precise location and mode of CWD development is not known. The condition was first noted in 1967 in research mule deer herds in Colorado, but not confirmed as a TSE until the 1970s. By the late 1970s, CWD was recognized in captive facilities in Colorado and Wyoming in mule deer, black-tailed deer, and elk. In 1981, the disease was identified first in the wild in elk in Colorado, followed shortly by mule deer in 1985 in both Colorado and Wyoming. At that time, an endemic zone for the disease was established in those states. CWD, however, spread to captive herds in Saskatchewan, Canada in the mid-1990s, and to Oklahoma and Nebraska, and wild cervids in Saskatchewan by the year 2000.
It was not until 2001 that CWD was identified in white-tailed deer, in South Dakota wild herds, and in a captive herd in Nebraska. In the following years, CWD spread to Minnesota, Wisconsin, New Mexico, Utah, Illinois, Kansas, Virginia, North Dakota, Iowa, Pennsylvania, Texas in 2012, and finally Ohio in 2014. In 2015, Michigan confirmed the first case of CWD in wild white-tailed deer. Currently 21 states and 2 Canadian provinces have CWD.
While CWD was first detected in captive mule deer, it has long-since spread to other cervids. Early reports indicated that transmission outside of mule deer was not possible, followed shortly by infection detected in elk. Eventually, infections in white-tailed deer, moose, and black-tailed deer (sub-species of mule deer) were detected. More recently, red deer were determined susceptible to infection in a research facility.
Current Status
Credit: Chronic Wasting Disease Alliance