Got Mice?

Learn the risks of hantavirus and how to protect yourself

It’s a glorious day. You decide you want to do some yard work or cleaning outside. You head out to get your tools; you’re ready to go! But wait, is that a mouse nest?

In Washington, deer mice can carry hantavirus, which can cause Hantavirus Pulmonary Syndrome (HPS) in humans. HPS is a severe, sometimes fatal respiratory disease. We get reports of 1 to 5 cases of HPS each year in Washington. People can develop HPS by breathing in air that carries the virus; through contact with mouse saliva, urine, droppings, or nesting material; or from a mouse bite.

If you disturb mouse nests, droppings, urine, or saliva, this can create small particles that contain the virus. These particles travel through the air and can be harmful to breathe in. You can prevent those particles from getting into the air by using “wet cleaning methods.” This is a vital step in reducing the risk of infection when you’re cleaning up after mice or other rodents, like rats.

6 wet-cleaning steps to reduce the risk of infection

It’s important to eliminate or minimize contact with mice. When you’re cleaning mouse-infested areas, use these steps to reduce the risk of infection:

1. Wear rubber, latex, vinyl, or nitrile (synthetic rubber) gloves.

2. Ventilate the space before cleaning by opening doors and windows for at least 30 minutes.

3. Avoid stirring up dust; don’t vacuum, sweep, or use cleaning methods such as dry dusting.

4. Thoroughly wet the contaminated areas — including trapped mice, droppings, and nests — with a 10% bleach solution. Here’s how to do it.

• Mix 1½ cups of household bleach in 1 gallon of water (or 1 part bleach to 9 parts water).
• Let everything soak for 10 minutes.
• Remove all the nest material, mice, and/or droppings with a damp towel.
• Then mop or sponge the area with the bleach solution.

5. Double-bag the waste before you throw it away, preferably in yard waste.

6. Wash gloves with disinfectant or soap and water before removing them, then wash your hands with soap and water after removing your gloves.

Keep mice and other rodents out of your home

• Seal cracks and gaps larger than ¼ inch in buildings, including around window and door sills, under sinks around the pipes, and in foundations, attics and any potential rodent entry point.
• Trap indoor rats and mice with snap traps.
• Keep food, including pet food, in mouse-proof containers.

Hantavirus cannot spread from person to person. If you think you were exposed to deer mice or mouse nests, watch for symptoms such as fever, muscle aches, and shortness of breath for up to eight weeks after exposure. If you have symptoms, see your health care provider and mention your exposure to deer mice.

For more information

In this video Dr. Scott Lindquist, MD, MPH, state epidemiologist for communicable diseases, provides tips on protecting you and your family from hantavirus.

Our Rodents webpage explains how to avoid attracting rodents, seal your home, trap rodents, and clean up after rodents.

CDC offers guidance on cleaning and disinfecting vehicles with rodent infestations. Rodents may build nests in cars, trucks, campers, and other vehicles that are not used often. Virus particles can blow onto passengers through the air vents and may pose a risk to people who use the vehicle.

More Information

Information in this blog changes rapidly. Sign up to be notified whenever we post new articles. For more information from the Washington State Department of Health, visit doh.wa.gov.

Questions about COVID-19? Visit our COVID-19 website to learn more about vaccines and booster doses, testing, WA Notify, and more. You can also contact the Department of Health call center at 1–800–525–0127 and press # from 6 a.m. to 10 p.m. Monday, and 6 a.m. to 6 p.m. Tuesday — Sunday and observed state holidays. Language assistance is available.