Do House Mice Carry Diseases?

Developed in consultation with Dr. Jorge Parada, Medical Advisor for the National Pest Management Association

One of the most shriek-inducing pests you will find in the home is a rodent. House mice, specifically, are the most encountered. Not only are they a nuisance, but house mice also carry diseases.

The bacteria and diseases carried by mice in the house can be harmful to humans. These small pests are expert contortionists, capable of squeezing through openings the size of a dime, meaning vigilant prevention is key to avoiding any infestations.

How Do House Mice Spread Diseases?

Diseases from house mice can be spread to humans by:

• Handling live or dead house mice.
• Direct contact or inhalation of dust contaminated with house mice feces, urine, or saliva.
• Getting bitten by house mice.
• What Diseases Do House Mice Carry?

House mice do carry many diseases including salmonella, rat bite fever, hantavirus, and lymphocytic choriomeningitis. Knowing how you can catch these diseases from house mice and what symptoms they bring can help protect you and your family. However, if you suspect an infestation, professional for help. 

1. Salmonella

Found in many places, including raw food and animal droppings, salmonella is the bacteria that causes salmonellosis. House mice can spread salmonella from their droppings and by contaminating items in your home just by touching them.

Humans that develop salmonellosis will experience digestive issues such as cramping, fever and diarrhea. These symptoms should only last a couple of days, but the elderly, young children, and those with weakened immune systems may require additional treatment.

For most, the illness is not treated with antibiotics and will need to be waited out. Unfortunately, in extreme cases, salmonellosis can cause sepsis and become a life-threatening illness.

2. Rat Bite Fever (RBF)

House mice also carry rat-bite fever, also known as RBF or Haverhill fever. This is an infectious disease caused by two bacteria strains: Streptobacillus moniliformis (found in the U.S.) and Spirillum minus (found in Asia).

Most people become infected after handling rodents like house mice that carry the disease or by consuming food or water contaminated with the bacteria. It is particularly important to watch out for any symptoms if you have been scratched or bitten by a house mouse. Early diagnosis and proper treatment are crucial as this disease can be fatal.

Common symptoms of streptobacillary RBF include fever, vomiting, headache, joint pain, and rash. The rash, appearing as a flat, reddened area with bumps, may appear on the hands and feet days after becoming infected. Antibiotics are the only treatment for this illness and can be effective at curing the disease.

3. Hantavirus

First recognized in 1993 in the southwestern United States, Sin Nombre Hantavirus Centers for Disease Control and Prevention, some hantaviruses can cause a rare but deadly disease called Hantavirus Pulmonary Syndrome (HPS).

In the U.S., Hantavirus is most commonly carried by deer mice. But white-footed mice, cotton rats, rice rats, and house mice are known carriers of Hantaviruses causing HPS. The virus is usually transmitted when rodent urine, droppings or nesting materials are stirred up, becoming airborne (often while cleaning a cabin, garage or home) and are inhaled by people.

Symptoms of Hantavirus include fatigue, fever and muscle aches and they usually appear 1-5 weeks after exposure. Four to 10 days after the initial phase of the illness is when late symptoms of Hantavirus may develop, including coughing, difficulty breathing, low blood pressure, and irregular heart rate. Confirmation of infection is achieved by a blood test. There is no curative directed therapy for this virus, but with early recognition and supportive treatments, prognosis for the patient improves.

4. Lymphocytic Choriomeningitis (LCM)

LCM is an infectious disease that house mice carry that is caused by the lymphocytic choriomeningitis virus (LCMV). House mice are the main host of this disease, with an estimated 5 percent of house mice carrying and transmitting it.

As with Hantavirus, this virus can be transmitted after exposure to rodent droppings or nesting materials. Physical contact with an infected rodent, especially from bites or scratches, can lead to infection. Additionally, pregnant persons can transmit LCM to their offspring causing birth defects or even miscarriage.

There are two phases of this infection: non-specific, flu-like symptoms and neurologic disease. The first phase has symptoms such as fever, lack of appetite, muscle aches and headaches. The second phase, according to the CDC, includes symptoms like meningitis (stiff neck, headache, etc.), encephalitis (sensory disturbances, motor abnormalities, drowsiness, etc.) and meningoencephalitis. Most who develop neurological disease related to LCMV survive but often require hospitalization and supportive care.

How to Prevent Diseases Carried by Mice in the House

Now that we know house mice do carry diseases, it’s important to prevent rodents like them from infecting you and your family. The best method of prevention is avoiding contact with rodents and keeping up with cleanliness and best hygienic practices. House mice can reproduce quickly, making it difficult to control an infestation. There are many ways to spot house mice in your home, such as droppings, gnaw marks, nests, and more.

By the time an infestation is noticed, mice have likely contaminated several items in your home, such as countertops, your food, and even your toothbrush. Therefore, it is important to work with a pest control professional if you spot a mouse in your house because it is essential to quickly get ahead of the problem.

If mice have infested an area of the home, cleanup is critical. Be sure to wear proper protective gear such as gloves and masks to protect you from coming into contact with destroyed items and nesting material that could be soaked in urine and feces.