Be careful about hantavirus

Montana Living

State health officials remind Montanans to take precautions to avoid hantavirus this spring


The Department of Public Health and Human Services (DPHHS) and local public health agencies remind Montanans and visitors to the state to be aware of the risk of hantavirus and to take precautions to avoid rodent exposures.


“Although hantavirus infection can occur during any month, the risk of exposure is increased in the spring and summer as people clean cabins and sheds, and spend more time outside in the vicinity of rodents,” said DPHHS epidemiologist Rachel Hinnenkamp.


With 43 cases of hantavirus reported since its recognition in 1993, Montana has one of the highest rates of infection in the United States. Early symptoms include fatigue, fever and muscle aches with progression include coughing and extreme shortness of breath. Hantavirus infection can cause severe illness; about 25 percent of Montana’s cases have resulted in death. Supportive medical care is essential to survival and, if diagnosed early, specific antiviral medications may help with recovery. 


Studies have shown that deer mice (Peromyscus maniculatus) are the most common host of the virus, and are well dispersed throughout Montana. People can become infected with hantavirus when saliva, urine, or droppings from an infected deer mouse are stirred up and inhaled. It is important to avoid activities that raise dust, such as sweeping or vacuuming, if there are signs of rodents in the area.


The best way to protect yourself from hantavirus is to control rodent populations in the places you live and work by sealing up holes to prevent entry and using snap traps to eliminate any mice indoors. You can also reduce rodent populations near dwellings by keeping grass and shrubbery near the home well-trimmed, and moving woodpiles at least 100 feet from the dwelling and raising them at least one foot off the ground.


You can protect yourself while cleaning areas contaminated by rodent droppings by taking the following precautions:

  • If cleaning an area such as a cabin, camper or outbuilding, open windows and doors and air-out the space for 30 minutes prior to cleaning.
  • Wear rubber or plastic gloves.
  • Thoroughly spray or soak the area with a disinfectant or a mixture of bleach and water to reduce dust. Let soak for 5 minutes.
  • Wipe up the droppings with a sponge or paper towel, and discard after use.
  • Clean and disinfect the entire area with disinfectant or bleach solution.
  • Wash hands thoroughly with soap and warm water after removing and discarding the gloves.
  • Avoid sweeping or vacuuming areas with rodent droppings and urine, as the action can stir up dust and aerosolize the droppings.

More information on hantavirus and its prevention can be found on the DPHHS website at

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