Chronic wasting disease (CWD) is an evolving prion disease of cervids (deer, elk 
and moose) that has been recognized in North America and Korea. Infection of 
non-cervid reservoir or transport species in nature is not reported. However, 
the ferret (Mustela putorius furo) is susceptible to CWD after experimental 
inoculation. Here, we report that infection of ferrets with either of two ferret 
CWD isolates by various routes of exposure has revealed biologically distinct 
strain-like properties distinguished by different clinical progression and 
survival period. The isolates of ferret CWD were also differentiated by the 
distribution of the infectious prion protein (PrP(CWD)) in the brain and 
periphery, and by the proteinase K sensitivity of PrP(CWD). These findings 
suggest that diversity in prion conformers exists in CWD-infected cervids.