Abstract

Plague appears to be a significant obstacle to successful reestablishment of lynx (Lynx canadensis) in Colorado. Yersinia pestis infections have been confirmed in six Canadian lynx reintroduced into Colorado as part of an ongoing species recovery program. Since 1999, plague was the primary cause in four of fifteen natural deaths, possibly contributed to one of six hit-by-vehicle deaths, and killed at least one kitten. In an attempt to minimize these impacts in future restoration efforts, we evaluated a recombinant capsular F1-V fusion protein vaccine that is safe and effective in black-footed ferrets. During January-April 2004, we vaccinated and serially bled 10 captive female lynx held in southwestern Colorado prior to their release in April 2004; 10 unvaccinated lynx served as controls. We observed no adverse effects of either the primary vaccine or booster doses on captive lynx. As of 15 March 2004, our study is still underway and serology results are pending. Based on observations to date, F1-V vaccine appears to be a safe vaccine in lynx; serologic responses and efficacy in reducing plague-related mortality remain to be determined.