What Diseases Can Mice Transmit to Humans?

Mice: An Often Underestimated Disease Vector

In Montreal, house mice (Mus musculus) are among the most common rodents found in homes. While their small size may seem harmless, these animals carry numerous potentially serious diseases. Their droppings, urine, and saliva can contaminate surfaces, food, and even the air you breathe.

Hantavirus: A Serious Respiratory Danger

Hantavirus is one of the most dangerous diseases transmitted by mice. It spreads primarily through inhalation of particles from dried mouse droppings, urine, or nests. Initial symptoms resemble a severe flu, but it can progress to Hantavirus Pulmonary Syndrome (HPS), a potentially fatal condition with a mortality rate of approximately 38%. Never sweep or vacuum mouse droppings dry, as this disperses viral particles into the air.

Salmonellosis: Food Contamination

Mice frequently carry Salmonella bacteria. They contaminate food and preparation surfaces with their droppings and urine. A single mouse can produce 50 to 75 droppings per day.

• Symptoms: diarrhea, abdominal cramps, fever, nausea, vomiting
• Duration: typically 4 to 7 days
• At-risk populations: children, elderly, immunocompromised individuals

Leptospirosis: A Dangerous Bacterial Infection

Leptospirosis is caused by Leptospira bacteria found in rodent urine. Transmission occurs through contact with contaminated water or surfaces. Severe cases can lead to kidney or liver failure. Montreal's spring thaw and flooding episodes can promote bacterial spread in damp basements.

Allergies and Asthma: A Chronic Risk

Mouse droppings, urine, and skin dander contain allergenic proteins that trigger allergic reactions and asthma attacks. Studies show up to 82% of urban homes have detectable mouse allergens. Children are particularly vulnerable, with chronic exposure linked to increased childhood asthma risk.

Lymphocytic Choriomeningitis (LCM)

The LCM virus is transmitted by common house mice through inhalation of contaminated particles. It is particularly dangerous for pregnant women, as it can cause birth defects or miscarriage. Symptoms range from fever and headache to meningitis in severe cases.

How to Protect Yourself

• Seal entry points: mice can squeeze through openings as small as a dime
• Store food properly: use airtight glass or metal containers
• Clean safely: wear gloves and a mask; dampen droppings with bleach solution before collection
• Eliminate water sources: fix leaks and remove standing water

When to Call a Professional

If you notice signs of a mouse infestation -- droppings, wall noises, gnaw marks -- act quickly. A female mouse can have up to 10 litters per year. At 514 Extermination, our certified technicians use safe and effective methods. Visit our rodent extermination service for rapid intervention across greater Montreal.