Chronic Wasting Disease in Free-Ranging Wisconsin White-Tailed Deer

Three White-tailed Deer shot within 5 km during the 2001 hunting season in Wisconsin tested positive for chronic wasting disease, a prion disease of cervids.Subsequent sampling within 18 km showed a 3% prevalence (n=476).This discovery represents an important range extension for chronic wasting disease into the eastern United States.C hronic wasting disease (CWD) is degenerative and usually considered to be fatal in White-tailed Deer (Odocoileus virginianus), Mule Deer (O.hemionus), and Elk (Cervus elaphus) associated with the presence of transmissible protease-resistant prion proteins (PrP cwd ) (1,2).Although the transmission route of PrP cwd is unknown, it may be transmitted in deer and elk by direct contact or indirectly from the environment (1,2).In experiments, clinical signs have appeared as early as 15 months after exposure (1) and include weight loss, anorexia, repetitive behaviors, hyperesthesia, and intractability.Signs progress to severe emaciation, extreme behavioral changes, excessive salivation, tremors, and mild ataxia (1,2).CWD was first recognized in captive Mule Deer in Colorado (3) and subsequently described in the free-ranging cervid populations of Colorado and Wyoming (1); prevalence in these disease-endemic areas varies spatially and among the three sympatric cervid species (4).Before its discovery in Wisconsin, CWD was detected in captive cervid farms in Colorado, Nebraska, South Dakota, Oklahoma, Kansas, Montana (USA), as well as Alberta, Saskatchewan (Canada), and South Korea (1).Apart from the contiguous