roosting site for one winter season ranged from 391,552 to 599,032 kg. CWD prions adhere so tightly to soil surface particles that the ground becomes a source of infection and may be a major route of transmission due to frequent ground contact when animals in the deer family graze. Alternative Etiologies The prion theory of CWD and spongiform encephalopathies in general has been challenged, most prominently by Dr. Frank Bastien of Louisiana State University. He argues the disease may be caused by a bacterium known as a spiroplasma. Additional theories include exposure to new industrial chemicals causing progressive brain damage. Prevention By 2012, a voluntary system of control was published by APHIS in the US Federal Register. It depended on voluntary minimum standards methodology, and herd certification programs to avoid interstate movement of the disease vector. It was based on a risk management framework. As of August 2019, APHIS law in 9 CFR Part 55 - CONTROL OF CHRONIC WASTING DISEASE dealt with this problem. Introduced for the 2019 Minnesota hunting season, a no-cost deer carcass-incineration program was rolled out by Crow Wing County officials hoping to stem the spread of CWD in the region. CWD was found among wild deer in Crow Wing County for the first time in January 2019. The voluntary program encourages both residents and visiting hunters to bring harvested deer carcasses to the county landfill east of Brainerd, Minnesota for incineration and disposal. Diagnosis Diagnosis is based on post mortem examination (necropsy) and testing; examination of the dead body is not definitive, as many animals die early in the course of the disease and conditions found are nonspecific; general signs of poor health and aspiration pneumonia, which may be the actual cause of death, are common. On microscopic examination, lesions of CWD in the CNS resemble those of other TSEs. In addition, scientists use immunohistochemistry to test brain, lymph, and neuroendocrine tissues for the presence of the abnormal prion protein to diagnose CWD; positive IHC findings in the obex is considered the gold standard. Conventional CWD diagnostic strategies and seeded amplification methods for amplifying CWD prions in vitro include: immunohistochemistry (IHC), western blotting (WB), enzyme immunoassay (EIA), protein misfolding cyclic amplification (PMCA), and real time quaking-induced conversion (RT-QuIC). Available tests, as of July 2019, at the CFIA were not sensitive enough to detect the prion in specimens from animals younger than a year old. Strategies