A Colorado man is hospitalized with the rarest and deadliest form of the plague.

Jennifer House, a spokeswoman for the Colorado Department of Public Health, said the man is infected with pneumonic plague and is the first case seen in the state since 2004.  The man’s identity is being kept from the public but officials say he was exposed in Adams County near Denver.

“He’s on treatment long enough to not be transmissible,” House told Bloomberg News.

She said that doctors believe he contracted the disease from his dog.

“We don’t think it’s out in our air,” House said. “We think it’s in our dead animal populations and dead rodent populations.”

Colorado has had 60 cases of plague since 1957 and nine people have died from the disease.  There is no vaccine available for the plague in the U.S.  The most common is bubonic plague, which was known for outbreaks during the middle ages.

“The message we’re trying to get out is that the plague bacteria is present here in Colorado, and to take necessary precautions to avoid getting infected,” House said.