are being developed to allow for the quantification of prion burden in a tissue, body fluid, or environmental sample. As of 2015, no commercially feasible diagnostic tests could be used on live animals. As early as 2001 an antemortem test was deemed urgent. Running a bioassay, taking fluids from animals in the deer family suspected of infection and incubating them in transgenic mice that express the cervid prion protein, can be used to determine whether the cervid is infected, but ethical issues exist with this, and it is not scalable. A tonsillar biopsy technique has been a reliable method of testing for CWD in live deer, but it only seems to be effective on mule deer and white-tailed deer, not elk. Biopsies of the rectal mucosa have also been effective at detecting CWD in live mule deer, white-tailed deer, and elk, though detection efficacy may be influenced by numerous factors including animal age, genotype, and disease stage. It is possible for CWD prions to survive sterilization procedures involving an autoclave. Epidemiology North America The disease was first identified in 1967 in a closed herd of captive mule deer in contiguous portions of northeastern Colorado. In 1980, the disease was determined to be a TSE. It was first identified in wild elk and mule deer and white-tailed deer in the early 1980s in Colorado and Wyoming, and in farmed elk in 1997. The disease did not affect Canada until 1996. In May 2001, CWD was also found in free-ranging deer in the southwestern corner of Nebraska (adjacent to Colorado and Wyoming) and later in additional areas in western Nebraska. The limited area of northern Colorado, southern Wyoming, and western Nebraska in which free-ranging deer, moose, and/or elk positive for CWD have been found is referred to as the endemic area. The area in 2006 has expanded to six states, including parts of eastern Utah, southwestern South Dakota, and northwestern Kansas. Also, areas not contiguous (to the endemic area) areas in central Utah and central Nebraska have been found. The limits of the affected areas are not well defined, since the disease is at a low incidence and the amount of sampling may not be adequate to detect it. In 2002, CWD was detected in wild deer in south-central Wisconsin and northern Illinois and in an isolated area of southern New Mexico. In 2005, it was found in wild white-tailed deer in