Wild prairie dogs are less likely to contract the plague after they ingest peanut-butter-flavored bait that contains a vaccine against the disease, a study published by the U.S. Geological Survey has found.
The vaccine, developed specifically for prairie dogs by scientists at the USGS National Wildlife Health Center and the University of Wisconsin, elicits a protective immune response that can help them fight off infection after exposure to the disease.
It may also help save the endangered black-footed ferret.
“Plague is devastating to prairie dogs, a keystone species of grassland ecosystems,” said Tonie Rocke, a USGS scientist and the project lead. “Our goal in developing an oral plague vaccine is to provide another tool for land managers to reduce the effects of plague outbreaks on prairie dog colonies.”
In an effort to increase populations of endangered black-footed ferrets and conserve the prairie dogs they rely on for survival, Rocke said it’s essential for land managers to control outbreaks of the plague.
Once thought to be extinct, the black-footed ferret is now one of the most endangered mammals in North America, and plague is a major impediment to its recovery. Both ferrets and prairie dogs are highly susceptible to the disease.
“This (plague) reduction could have positive impacts on conservation of the threatened Utah prairie dog and survival of the endangered black-footed ferret – a prairie dog-dependent species,” Rocke said.
The current method for controlling plague consists of dusting prairie dog colonies with insecticide to kill fleas that transmit the pathogen. Although dusting has been effective in controlling the spread of plague, Rocke said it’s labor-intensive, and some flea species may develop resistance to the pesticide.
From 2013 to 2015, a consortium of 14 federal, state, tribal and non-governmental agencies worked together to field test the plague vaccine in all four prairie dog species present across seven western states, including Montana, Arizona, Colorado, South Dakota, Texas, Utah and Wyoming.
The study was organized under the Black-footed Ferret Recovery Implementation Team, a multi-agency effort led by the U.S. Fish and Wildlife Service. The study found that prairie dog survival rates were higher on vaccine-treated plots during plague outbreaks compared to plots that received placebo baits, suggesting that consumption of vaccine baits provided protection for prairie dogs.
Researchers anticipate that application of vaccine baits to larger prairie dog complexes on an annual basis will enhance protection against plague.
“Wildlife managers have struggled to recover ferrets and manage prairie dog colonies due to the devastating effects of plague,” said Dan Tripp, a Colorado Parks and Wildlife scientist and co-author on the USGS study. “It is our hope that use of the sylvatic plague vaccine in select areas, with the support of willing landowners, will help to limit the impact of plague to wildlife.”
The report was published this week in the journal EcoHealth.
For more information about USGS wildlife disease research, please visit the USGS National Wildlife Health Center website.