Abstract

We investigated evidence for strain variation in the chronic wasting disease (CWD)-associated prion (PrP^CWD) of deer (Odocoileus spp.), as well as the utility of domestic ferrets (Mustela putorius furo) as a common host for such studies. Ferrets (n=3 per group) were inoculated intracerebrally with brain material from single natural cases of CWD from northeastern Colorado that had occurred in a) a captive mule deer (O. hemionus) prior to 1985, b) a captive mule deer in 2000, c) a free-ranging mule deer, d) a captive white-tailed deer (O. virginianus) in 1999, and e) a free-ranging white-tailed deer; two additional groups of ferrets (uninoculated and inoculated with CWD-negative mule deer brain) were maintained as controls. Clinical signs and postmortem findings consistent with CWD in ferrets were observed in four of five groups inoculated with tissue from infected deer, but not in the free-ranging white-tailed deer or control groups. Incidence and incubation periods were consistent among affected groups. Moreover, Western blots (WB) revealed no apparent differences in glycosylation patterns among WB-positive ferrets. No strain variation in PrP^CWD was evident among these representative cases of CWD in captive mule deer and white-tailed deer and free-ranging mule deer from northeastern Colorado; however, no variation was expected among the three groups inoculated with materials from the same captive facility. Based on our experiences, domestic ferrets have limited utility as a laboratory model for studying CWD. Despite our findings, further investigation of potential strain variation among more geographically and epidemiologically distant cases of CWD in deer still appears warranted.