Mice can pose serious health risks to people because they carry germs and parasites that cause diseases. These health concerns arise not only from direct contact with mice, but also through their urine, droppings, saliva, nesting material, or the fleas and mites that live on them. Infection can happen when people breathe in dust contaminated with mouse waste, touch contaminated surfaces, or eat food the mice have come into contact with.

Key transmission routes:

• Hantavirus — breathing dust from dried droppings/urine (most important to prevent)
• Salmonellosis — eating food contaminated with mouse feces
• Leptospirosis — skin contact with urine-contaminated water or soil
• LCMV — direct contact with mice or their waste

Knowing which activities cause which disease determines the appropriate protective measures.

Diseases Directly Spread by Mice

Mice are well-known carriers of several diseases dangerous for humans. These include:

• Hantavirus Pulmonary Syndrome: This is a serious lung disease. People can get it by breathing in dust from dried mouse urine or droppings, especially in closed or poorly ventilated spaces. (CDC: Hantavirus)
• Salmonellosis: This is food poisoning that causes diarrhea and stomach cramps. Mice can contaminate food, utensils, and surfaces with their feces, spreading salmonella bacteria. (CDC: Salmonellosis)
• Leptospirosis: This disease comes from contact with water or soil contaminated with mouse urine. It can cause flu-like symptoms and, in severe cases, kidney or liver problems. (CDC: Leptospirosis)
• Lymphocytic Choriomeningitis Virus (LCMV): This virus, carried by house mice, can cause fever, headache, and even meningitis (inflammation around the brain and spinal cord). People get it by breathing in contaminated dust or handling materials touched by infected mice. (CDC: LCMV)
• Rat-Bite Fever: Mice bites or scratches — and even contact with surfaces contaminated by mouse droppings — can lead to this disease, which causes fever, rash, and joint pain.

In New Hampshire, the primary disease risk from house mice is Hantavirus Pulmonary Syndrome (HPS). While rare, HPS has been documented in NH and the broader New England region. The CDC notes that HPS has a mortality rate of approximately 38% in confirmed cases — early respiratory symptoms after mouse exposure should prompt immediate medical consultation.

Allergic Reactions and Asthma

A major health issue from mice is the triggering or worsening of allergies and asthma. Mouse urine, droppings, dander (skin flakes), and saliva contain proteins that can cause allergic reactions. When these proteins get into house dust and become airborne, people — especially children — can develop symptoms like sneezing, coughing, itchy eyes, rashes, and asthma attacks.

Indirect Transmission through Parasites

Mice also carry parasites such as fleas, mites, and ticks. These parasites can bite humans, causing irritation and sometimes carrying additional diseases like plague (caused by fleas), typhus, or rickettsialpox. Even if you don't touch a mouse, being in a space where mice have lived can expose you to these biting pests.

Food Contamination

When mice get into pantries, food stores, or kitchens, they contaminate food with their waste, saliva, or fur. This doesn't just cause spoilage — it can directly spread germs that make people sick. Eating even a small amount of food or water that's been contaminated, or using unwashed dishes exposed to mice, may result in infections.

Structural Damage and Fire Risk

Even though this isn't strictly a health issue, it's worth knowing that mice chew through wires, insulation, and wood. Chewed wires can cause electrical fires, putting everyone in the building at risk of injury or death.

Practical Steps to Reduce Mouse-Related Health Risks

• Seal all cracks and gaps in walls, floors, and foundations to keep mice out.
• Store food in airtight containers and clean up crumbs or spills immediately.
• Dispose of garbage regularly and keep bins tightly closed.
• Clean up mouse droppings or nests using gloves and a disinfectant, not by sweeping or vacuuming (which stirs up contaminated dust).
• If you notice signs of mice (droppings, urine smell, gnawed food), deal with it quickly — contact a professional pest control service if necessary.

Key Takeaway

In summary, mice are not just a nuisance — they're a real health hazard. They spread disease, cause allergies, contaminate food and water, and bring parasites into living spaces. Taking steps to keep mice out and cleaning up carefully if they get in is crucial for protecting your health and your family's safety.

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