If you’ve been around summer cabins, barns or garden storage sheds, you’ve probably run across mice or mouse droppings. In much of rural Montana, mice are so pervasive you may have become fairly laid back about seeing them.
But rodents, particularly deer mice, can carry the virus that causes hantavirus pulmonary syndrome, a potentially deadly disease. When rodent droppings, urine, salvia or nesting materials are disturbed, the air may become contaminated with the virus. People get hantavirus from breathing the contaminated air.
Two confirmed cases of hantavirus in Montana this spring should give everyone pause to think about how they handle rodent infestations. Since 1993, when the first cases were recognized in the Four Corners area of New Mexico, 37 cases of hantavirus have been reported in Montana. Only New Mexico has had more cases of hantavirus per capita.
While hantavirus can occur in any season, it’s more likely when people are cleaning out cabins, sheds or other outbuildings.
The best way to prevent the virus is to eliminate or control rodents around where you live or work. Prevention guidelines developed by the Centers for Disease Control and Prevention boil down to three main steps: Seal, trap and clean.
Seal gaps and holes inside and outside homes. Mice can squeeze into holes the size of a nickel. Plug gaps around vents and plumbing, foundations, attics and crawl spaces. Check the border between floors and walls. Fill small holes with steel wool and caulk. Use lath screen or lath metal, cement, hardware cloth or metal sheeting to fix large holes. Fix gaps in trailer skirting and use flashing around the base of the house.
Reduce rodent shelter and food sources, such as hay or wood piles, near your home. Keep grass cut short and brush trimmed. Keep grains and animal feed, including pet food and bird seed, in rodent-proof metal or thick plastic containers with tight-fitting lids. Store garbage and trash in rodent-proof containers.
Trap mice with spring-loaded traps and follow the manufacturer’s instructions.
When you’re cleaning, take the following precautions:
Do not stir up dust by sweeping or vacuuming up droppings, urine or nesting materials.
Wear rubber, latex, or vinyl gloves.
Spray rodent urine and droppings with a disinfectant, or mixture of bleach and water. Let soak five minutes. The recommended concentration of bleach is one part bleach to 10 parts water.
Use a paper towel to pick up urine and droppings. Dispose of the waste in the garbage.
After removing droppings and urine, disinfect items that might have been contaminated. Then clean the whole area. Mop floors with a disinfectant. Disinfect countertops, cabinets, drawers and other surfaces. Steam-clean or shampoo rugs and upholstered furniture. Wash contaminated clothing in hot water with laundry detergent.
Before taking off your gloves, disinfect them. After removing your gloves, wash your hands thoroughly with soap and warm water.
Although hantavirus is rare, the disease cannot be taken lightly. Early symptoms of the illness usually seem flu-like. See your health care provider immediately if you have been exposed to rodents or rodent infestations and have symptoms including fever, deep muscle and body aches, chills, vomiting, diarrhea and fatigue. Be sure to tell your provider you may have been exposed to rodents. As the illness progresses, other symptoms appear, including a severe shortness of breath and the feeling of suffocation as lungs fill with fluid.
For further information, check the Centers for Disease Control and Prevention’s website www.cdc.gov/hantavirus.
Josh Juarez is the lead registered sanitarian with Environmental Health Services at RiverStone Health. He can be reached at 406-651-6548 or firstname.lastname@example.org.