Spring cleaning caution
By Crystal Thompson
With spring cleaning at the top of many rural Montanan's to-do lists, it is important to be informed about the dangers that exist in old barns, sheds and garages.
In 1993, an outbreak of hantavirus was contained in the four-corners area of the United States. Hantavirus has several strains, but probably the most recognized in our area is the one carried by deer mice. This strain can be contracted by humans who breathe in dust particles that contain feces or urine from contaminated mice.
In late 1993, Dr. Richard Douglas, Professor at Montana Tech, began studying hantavirus by capturing deer mice throughout Montana and taking blood samples from the rodents. In June 1994, scientists in Montana had captured more mice who tested positive for the hantavirus than New Mexican scientists had captured in six years of study. Douglas presented a workshop on hantavirus at a Great Falls Area Safety and Health Workgroup (GASH) on Thursday.
Douglas and his team have been capturing and studying deer mice for eight years, and have performed various experiments to test the behaviors of infected deer mice. Hantavirus does not kill the rodents it infects, however it can be fatal to humans.
Douglas said that mice can live with the hantavirus because it has evolved within their species; however, because the virus is foreign to humans, their ability to fight it is limited. Since 1993 there have been three documented cases of death from hantavirus in Montana; in areas near Cut Bank, Great Falls and Malta.
Douglas' research team began studying deer mice as they entered buildings to prove the theory that indoor mice have a higher hantavirus infection rate. For the experiment, Douglas used three makeshift wooden boxes he called "mouse hotels"; one house had food inside, one had bedding and one was empty. An electronic device was attached near the opening of the house and kept track of mouse activity. The study proved that nearly the same number of mice entered all three housings, but after several days the house with food had more continuous activity.
Douglas theorized that mice enter a shelter regardless of what's inside, however, if food is present, they are more likely to make a home there. Upon his discovery, Douglas went back through documented cases of hantavirus and found that over 90 percent of fatal cases could be directly associated with buildings. He said that mice are likely to enter any building with an opening, including houses and cabins.
Douglas said that exposure to hantavirus increases in rural areas where barns and sheds are deteriorating, and are thereby allowing mice to enter with ease. He said that the only sure way to be protected from hantavirus is to completely mouse-proof all buildings. When cleaning, Douglas said that it is imperative to wear a HEPA-filter mask to keep from breathing dust particles which may contain the virus.
Douglas and his team continue to study mice captured from six sites throughout Montana. He told the GASH group that although the chance of contracting hantavirus remains low, it is easy to lower it by taking precautions when cleaning structures. These precautions include spraying down all areas with a mixture of 30 percent bleach, 70 percent water combination, airing out buildings before cleaning and wearing a HEPA-filter mask when working in high-risk areas like dusty barns or cabins.