MADISON, Wis. (AP) — A vaccine developed in Wisconsin has been shown to protect prairie dogs from plague, a bacterial disease that has sickened three people in New Mexico this year. Researchers reported that prairie dogs that ingested vaccine baits were twice as likely to survive outbreaks of plague as prairie dogs that didn’t get the vaccine. The vaccine was developed at the University of Wisconsin-Madison and the U.S. Geological Survey’s National Wildlife Health Center in Madison. The three-year study involved 58 colonies of the grassland rodents in seven states. Researchers placed vaccine baits flavored with peanut butter in 29 prairie dog colonies in Arizona, Colorado, Montana, South Dakota, Texas, Utah and Wyoming. Scientists are now studying the use of drones and all-terrain vehicles to dispense the baits.