Author(s): Jerry L. Godbey, Dean E. Biggins, and Della Garelle
Abstract: Plague, a disease caused by the bacterium Yersinia pestis, was introduced into North America ca. 1900 and is now common within the ranges of three species of prairie dogs (Cynomys spp.) that collectively composed the former range of the highly endangered black-footed ferret (Mustela nigripes). An experimental population of black-footed ferrets living in quasi-natural outdoor pens suffered 90 percent mortality after they ate prairie dogs infected with Y. pestis. Lethal and sublethal exposure of Siberian polecats (Mustela eversmannii) subsequently released into those pens suggested that live Y. pestis can be maintained in animal tissues within burrow systems for at least 2 months. A combination of low levels of prairie dog mortality and persistence of Y. pestis in dead hosts may pose a chronic hazard for free-ranging black-footed ferrets in areas where plague is enzootic.