(Cheyenne, Wyo.) – A Wyoming Department of Health representative says hantavirus infection remains a potential health threat when mice get into closed locations and leave their droppings behind.

Eleven human hantavirus cases, including six that resulted in death, have been reported in Wyoming since 1999.

Infected rodents can infest garages, campers, cabins and barns and shed hantavirus through urine, droppings and saliva.  People can become seriously ill if they breathe in the infectious aerosols that are created when contaminated, dried materials are disturbed. Infection is also possible when the virus touches broken skin or mucous membranes, if it is swallowed or after bites.

“Hantavirus remains dangerous and is sometimes fatal in the cases we see,” said Clay Van Houten, Infectious Disease Epidemiology Unit manager with the Wyoming Department of Health. “We want people to be aware of the threat and be cautious, especially if they are going into places that have been closed for a while.”

If a building has been closed and unoccupied for a long time, doors and windows should be opened for ventilation at least 30 minutes before cleanup work begins. When working in places that are especially dirty, dusty or infested with mice, extra protective clothing or equipment should be worn such as coveralls, shoe covers and special face masks known as respirators.

Van Houten recommended several basic cleanup guidelines:

  • During cleaning, wear rubber, latex, vinyl, or nitrile gloves.
  • Spray rodent urine and droppings with a disinfectant or bleach solution until thoroughly soaked.  Combining 1 ½ cups of household bleach with 1 gallon of water is a good choice.
  • Do not vacuum or sweep urine, droppings, nesting materials or contaminated surfaces until they have been disinfected.
  • Use a paper towel (while wearing gloves) to pick up urine and droppings.
  • After the droppings and urine have been removed, disinfect items that might have been contaminated.

– Wyoming Department of Health