Do Mice Actually Carry Diseases? What Montreal Residents Should Know
When someone tells you "it is just a mouse," they are wrong. Mice are not just a nuisance. They are a documented public health risk.
Here are the specific diseases associated with house mice in Canada — not hypotheticals, but real health risks backed by Health Canada and the Public Health Agency of Canada.
Diseases Carried by House Mice
Hantavirus
What it is: A viral infection transmitted through inhalation of dust contaminated with mouse droppings, urine, or nesting material. Severity: Hantavirus Pulmonary Syndrome (HPS) has a fatality rate of approximately 30-40% according to the Centers for Disease Control and Prevention. This is not a minor illness. Risk in Montreal: The deer mouse (Peromyscus maniculatus) is the primary carrier. White-footed mice, found in Quebec, can also carry hantavirus. The risk is highest when cleaning enclosed areas with heavy mouse contamination — attics, cabins, sheds, crawl spaces. Prevention: Never sweep or dry-vacuum mouse droppings. Wet them with a bleach solution (1 part bleach to 10 parts water) first. Wear gloves and an N95 mask when cleaning contaminated areas.Salmonellosis
What it is: A bacterial infection (Salmonella) transmitted when mice walk across food preparation surfaces or contaminate stored food. Severity: Causes diarrhea, fever, and abdominal cramps lasting 4-7 days. Usually resolves without treatment in healthy adults. Can be serious for young children, elderly, and immunocompromised individuals. Risk in Montreal: Present wherever mice access kitchen surfaces and food storage. The risk is year-round in infested dwellings. Prevention: Store all food in sealed containers. Clean countertops and surfaces with disinfectant. Never leave food out overnight.Leptospirosis
What it is: A bacterial infection transmitted through contact with water or surfaces contaminated with mouse urine. Severity: Ranges from mild flu-like symptoms to severe liver and kidney damage. Severe cases (Weil's disease) can be fatal without treatment. Risk in Montreal: Present in urban areas where rodent urine contaminates water sources, basement floors, and crawl spaces. Risk increases after flooding events. Prevention: Wear gloves when cleaning areas with rodent activity. Avoid contact with standing water in basements where mice are present.Lymphocytic Choriomeningitis (LCM)
What it is: A viral infection transmitted through exposure to fresh mouse urine, droppings, saliva, or nesting material. Severity: Usually causes a mild flu-like illness. In rare cases, can cause meningitis or encephalitis. Particularly dangerous during pregnancy — can cause birth defects. Risk in Montreal: The common house mouse is the primary reservoir. Risk is highest in homes with active infestations. Prevention: Pregnant women should avoid all contact with mice and mouse-contaminated areas. Do not clean mouse-contaminated areas during pregnancy.Mouse Allergens — The Hidden Health Risk
Beyond diseases, mouse allergens are a major health concern that receives less attention.
Mouse urine proteins are one of the most potent indoor allergens identified. According to research published in the Journal of Allergy and Clinical Immunology, mouse allergen exposure is associated with:
- Increased asthma symptoms in sensitized individuals
- Higher rates of childhood asthma in urban environments with rodent infestations
- Allergic rhinitis (chronic nasal congestion, sneezing, itchy eyes)
Who Is Most at Risk
| Group | Primary Risk | Action | |---|---|---| | Children under 5 | Mouse allergens triggering asthma | Professional cleaning of contaminated areas after extermination | | Pregnant women | LCM virus risk to fetus | Avoid all contact with mouse-contaminated areas | | Immunocompromised | All diseases — higher severity | Prioritize rapid extermination and professional decontamination | | Elderly | Salmonellosis, leptospirosis complications | Food safety precautions, avoid basement areas with activity | | People with asthma | Mouse allergen exacerbation | Reduce allergen exposure through cleaning and HEPA filtration |
Safe Cleanup After Mouse Infestation
1. Ventilate the area for 30 minutes before cleaning (open windows and doors) 2. Wear gloves (rubber or latex) and an N95 mask 3. Do NOT sweep or vacuum dry droppings — this aerosolizes hantavirus particles 4. Spray droppings and nesting material with a bleach solution (1:10) and let soak for 5 minutes 5. Wipe up with paper towels and dispose in a sealed plastic bag 6. Mop hard floors with bleach solution 7. Steam clean carpets and upholstered furniture if contamination was extensive 8. Wash hands thoroughly with soap and hot water after cleanup 9. Wash clothing worn during cleanup in hot water
For severe contamination (heavy droppings in an attic, crawl space, or enclosed area), consider professional decontamination. The cost ($300-$800) is justified by the health risk reduction.
Frequently Asked Questions
Can I get sick from just seeing a mouse?
No. Disease transmission requires contact with mouse droppings, urine, saliva, or nesting material — or inhalation of contaminated dust. Seeing a mouse run across the floor is not a disease exposure. The risk comes from the contamination they leave behind in areas you may not see.How soon should I exterminate if I have children?
Immediately. Children are the most vulnerable population for mouse allergen exposure and disease transmission. If you have children and confirm mouse activity, treat it as urgent — not something to "wait and see" about.Got a pest problem?
Extermination DMP serves Montreal, the South Shore, Laval & the West Island — 24/7.
Call 438-879-5706