Montana’s first 2015 case of hantavirus was recently discovered in Missoula County. Missoula City County Health Department Director Ellen Leahy says this case is the first diagnosed in Missoula County for over a decade.

Missoula County has not had a confirmed case since 2000, however, the deer mice are ever present and the fact that they could be carrying hantavirus at any time is ever present," Leahy said. "The most recent case was reported to us last week on either the 19th or the 20th."

BHantavirus has a high fatality rate and the recent discovery in Missoula has kicked-off a local investigation for deer mice, a species known for carrying the virus. Officials warn that because of the high rate of hantavirus in deer mice, all should be treated as if they have hantavirus.

"That sends us out into the environment to try to determine what places may have posed a risk, so that they can be dealt with and not pose a further risk," Leahy said. "We are not done investigating. We are on both private and public land and will continue the investigation at least through the end of the week."

Since tracking began in 1993, there has been a hantavirus fatality in Montana just about every three years. So far, there have been 39 diagnosed cases and only a handful of those were in Missoula County.