Interspecific comparisons of sylvatic plague in prairie dogs

Of the 3 major factors (habitat loss, poisoning, and disease) that limit ab undance of prairie dogs today, sylvatic plague caused by Yersinia pestis is the I factor that is beyond human control. Plague epizootics frequently ki ll > 99% of prairie dogs in infected colonies. Although epizootics of sylva tic plague occur throughout most of the range of prairie dogs in the United States and are well described, long-term maintenance of plague in enzootic rodent species is not well documented or understood. We review dynamics of plague in white-tailed (Cynomys leucurus), Gunnison's (C gunnisoni), and b lack-tailed (C ludovicianus) prairie dogs, and their rodent and flea associ ates. We use epidemiologic concepts to support an enzootic hypothesis in wh ich the disease is maintained in a dynamic state, which requires transmissi on of Y. pestis to be slower than recruitment of new susceptible mammal hos ts. Major effects of plague are to reduce colony size of black-tailed prair ie dogs and increase intercolony distances within colony complexes. In the presence of plague, black-tailed prairie dogs will probably survive in comp lexes of small colonies that are usually >3 km from their nearest neighbor colonies.