The term “sac mice” is an informal label for rodents like deer mice or white-footed mice found nesting in enclosed, undisturbed locations like storage bins or vehicle engines. Finding a mouse in such a space requires a careful approach, as certain wild mice can carry viruses that pose human health risks. Understanding the specific type of mouse and the associated risks is the first step in addressing the situation safely.
Identifying Deer Mice and Associated Risks
Distinguishing a deer mouse from a common house mouse is a direct way to assess potential health concerns. Deer mice have large black eyes and prominent ears. A defining feature is their bicolored fur; their bodies are a brownish or grayish color on top with a sharply defined white underbelly and feet. Their tails are also dark on top and light on the bottom, unlike the uniformly gray house mouse, which has a scaly, almost hairless tail.
The primary health concern with the deer mouse (Peromyscus maniculatus) is its role as a carrier of the Sin Nombre virus, which causes Hantavirus Pulmonary Syndrome (HPS), a severe respiratory illness. The virus is present in the mouse’s urine, droppings, and saliva. It is transmitted to humans when nesting materials are disturbed, causing microscopic particles to become airborne and be inhaled. Infection can also occur through direct contact with contaminated materials or from a bite.
Safe Cleanup Procedures
When dealing with a dead mouse or its droppings, avoid actions that could create airborne dust. Never sweep or vacuum rodent nests or waste materials. Instead, follow these steps for safe cleanup:
- First, ventilate the enclosed space by opening doors and windows for at least 30 minutes to allow air to circulate.
- Before beginning the cleanup, wear rubber or vinyl gloves and a well-fitting N95-type mask.
- Thoroughly soak the dead mouse, droppings, and any nesting materials with a disinfectant. A solution of one part household bleach to ten parts water is effective. Let the materials soak for a minimum of five minutes to neutralize the virus.
- Once disinfected, use paper towels to pick up the materials and place them into a plastic bag. Seal this bag, and then place it inside a second plastic bag before disposing of it in an outdoor trash receptacle.
- After the waste is removed, mop or sponge the entire area, including surrounding hard surfaces, with the bleach solution.
- Finally, disinfect your gloved hands before removing the gloves, and then wash your hands thoroughly with soap and water.
Preventing Infestations
Long-term prevention focuses on making your home and property less accessible and attractive to rodents. The first measure is to seal potential entry points. Inspect your home’s foundation, siding, and roofline for any cracks or holes larger than a dime, paying special attention to areas where utility lines enter the structure. Fill these gaps to deny entry.
Coarse steel wool is a useful material for plugging holes because mice cannot easily chew through it; secure it in place with caulk for a permanent seal. Applying weatherstripping to the bottom of doors, including the one leading from an attached garage into the house, can also close a common entry route.
Removing sources of food and shelter is another part of prevention. Store all food items, including pet food and birdseed, in airtight, rodent-proof containers. Reduce clutter around your home’s foundation, such as woodpiles or dense shrubbery, as these provide hiding places for mice. For mice already present, setting traps can be an effective control measure.