Science Center Objects

Sylvatic plague, caused by Yersinia pestis, is a bacterial disease transmitted by fleas that afflicts many mammalian species, including humans.

Plague is widespread throughout the western U.S. and frequently occurs in wild rodents. All four species of prairie dogs in the U.S. are particularly susceptible to plague, suffering high mortality rates during outbreaks (> 90%) and resulting in local extirpation and population reductions. As a keystone species of grassland ecosystems, prairie dog losses significantly impact numerous other species that depend on them for food or shelter, including endangered black-footed ferrets, burrowing owls, mountain plovers, and several canine and avian predators. Controlling plague is a vital concern for ongoing management and conservation efforts for prairie dogs and black-footed ferrets.

Prairie dog and SPV bait

A Gunnison's prairie dog eats a bait laden with the sylvatic plague vaccine. Prairie dogs in the wild are less likely to succumb to plague after they ingest peanut butter-flavored bait that contains a vaccine against the disease.

(Credit: Tonie Rocke, USGS. Public domain.)

Currently, plague is managed in prairie dogs through manual application of insecticides to burrows to kill the fleas that transmit Y. pestis. However, this process is labor intensive, and recent evidence suggests that fleas can develop resistance to the most frequently used pesticide.  

The USGS National Wildlife Health Center (NWHC), in conjunction with others, has developed and tested a sylvatic plague vaccine (SPV), deliverable to prairie dogs via palatable bait that offers an additional approach for plague management. From 2013-15, NWHC scientists conducted a large, collaborative field study to test the effectiveness of SPV in reducing mortality from plague in four species of prairie dogs in 7 western states. This study involved state, federal, tribal and non-government agencies organized under the Black-footed Ferret Recovery Implementation Team (BFFRIT), a multi-agency effort led by the US Fish and Wildlife Service. The study found that vaccine treatment increased prairie dog abundance and also increased survival at sites with plague outbreaks. However, ongoing research is needed to scale-up SPV use as a management tool and to determine if its use will provide benefits to other species, like black-footed ferrets, or whether it could be used to protect public health. Learn more about NWHC work on vaccines.

Additional Sylvatic Plague Vaccine Resources