Authorities have confirmed a dead squirrel in Aurora has tested positive for bubonic plague. This brings the total number of squirrels in the metro area who've tested positive for the plague to 15. Thirteen of those were found in or near Denver's City Park and another was found in Jefferson County. This is the first new outbreak of plague in tree squirrels in the Denver area since 1968, although cases of plague are relatively common in local prairie dog colonies. Since plague is spread by fleas, health experts are warning pet owners to take extra precautions with their dogs and cats.