RML Does A Tick-check and A Mouse Field Study
We've heard of hanta virus and Colorado tick fever - one spread by mice and other from tick bites. Two Rocky Mountain Laboratories field studies showed evidence of both viruses in the Bitterroot Valley. A field survey conducted by the Laboratory of Zoonotoic Pathogens showed an overall rate of 6.6 percent of ticks infected with Colorado tick fever. At a recent meeting of the RML Community Liaison Group, Microbiologist Brandi Williamson said that in 2012, ticks were collected from areas that were previously studied in the 1960s. After collecting 958 ticks, an average of 6.6 percent of the ticks had the virus that causes Colorado tick fever. There were areas where the infection rate was higher, such as Blodgett and Mill Creek. Historically, the results were nearly identical to field research done in 1959-60 and 1961-63. By the way, this is tick season in the Bitterroot. Remember, hikers, to check your body after your trip for ticks that might have hitched a ride on your clothing.
Williamson, from the RML Laboratory of Virology, also said a two-year field study to check the prevalence of Hanta virus in rodents showed evidence of that virus in the Bitterroot Valley. After live-trapping rodents on rental cabins in three areas of the valley in 2017 and 2018, researchers found evidence of Sin Nombre Hanta (SNV) virus in about 10 percent of the deer mice. That compares to a nearby survey that showed about 20 percent of SNV infected rodents in the Big Hole Valley and near Anaconda. The highest Bitterroot percentage was in the Alta area at the south end of the valley. With only 44 cases of human infection of SNV in the state since 1995, Montana still has one of the highest rates in the nation. Williamson emphasized that the virus is spread through the air. People should follow the well-publicized tips of cleaning out areas where field mice have nested. DON'T sweep the refuse out. That will only spread the virus into the air and into your lungs. Instead, spray the area first with a water and 10% bleach combination and clean up with a mop or sponge, then dispose of the cleaning material.