You’re more likely to get sick if you come in contact with fresh mouse droppings in a poorly ventilated space. The risk and type of infection may also depend on your location.

Rodents such as rats, mice, prairie dogs, and chipmunks are shy animals who usually avoid direct contact with people.

But even without frequent face-to-face contact, if you live near rodents, you’re at risk of developing the diseases that these animals are known to transmit.

Mouse droppings can harbor bacteria and viruses that can cause various kinds of sicknesses in humans. Several of these illnesses may be serious or even deadly for some people.

If you see small, dark droppings about the size and shape of rice grains in your yard, home, vehicle, school, or place of work, there may be a mouse — or many — nearby.

It’s important to carefully clean up mouse droppings and to ensure you remove the mice from your home.

Read on to learn more about your chances of getting a bacterial or viral disease from mouse droppings, and find out how you can take steps to avoid getting sick.

Some types of human infections from mouse droppings are more common than others, and infection rates vary worldwide.

For instance, salmonellosis is a common human infection that affects more than 90 million people worldwide each year and can be acquired from mouse droppings.

Other infections are rare but continue to affect people all over the world.

Rodents are found worldwide, and so are the diseases they carry. Infections often occur in rural areas where people have close contact with wildlife.

In the United States, rodent infections like hantaviruses are most common in the Western states, where rodents tend to live in higher populations than in other areas. This includes California, Arizona, Washington, New Mexico, and Colorado.

However, these illnesses can occur across the country in any place rodents inhabit.

A single mouse produces 50 to 75 droppings per day, so the presence of many mice can produce a large number of droppings.

Mouse droppings often collect in areas near where people reside, as mice are attracted to the warmth of vehicles and buildings and the food we cook, eat, and store.

Mouse and other rodent droppings can easily contaminate food, water, clothing, and bedding. Bacterial and viral diseases can be transmitted from mouse droppings when touched, inhaled, or accidentally ingested by a person.

How long can a virus survive in mouse droppings?

Viruses can remain infectious for varying amounts of time in different substances and on different surfaces.

Viruses like the hantavirus can be infectious in mouse droppings for up to 4 days. Time in the sun may shorten this period, but colder temperatures may lengthen it.

Bacteria like Salmonella can remain alive for many more days or even weeks in mouse droppings.

Illnesses commonly shed by mice in their droppings include:

Arenaviruses

Rodents carrying arenaviruses live across Europe, Asia, Africa, and the Americas. In many cases, arenaviruses can cause severe disease. Some can be transmitted from person to person through contact with items or the bodily fluids of individuals with the virus.

Lassa fever is a prominent illness caused by mouse droppings and urine in mice that live across several West African countries, including Sierra Leone and Nigeria.

Lassa fever can cause severe damage to your body and has a high fatality rate. Symptoms occur over days to weeks, and may include:

Approximately 2 in 10 people with Lassa fever may experience bleeding gums, eyes, or nose.

Other arenaviruses from mouse droppings can cause other illnesses with similar symptoms, including:

  • Chapare hemorrhagic fever
  • Luju hemorrhagic fever
  • Argentine hemorrhagic fever

Hantavirus

Rodents in Europe, Asia, and the Americas transmit hantaviruses. These viruses can cause severe illnesses.

In Europe and Asia, hantaviruses may cause hemorrhagic fever with renal syndrome. This serious condition causes a range of symptoms, such as:

In severe cases, it can lead to acute shock, low blood pressure, vascular leakage, and acute kidney failure.

In the Americas, hantavirus pulmonary syndrome (HPS) is a dangerous and sometimes deadly respiratory disease that you can get from mouse droppings. HPS can cause symptoms that progressively worsen over time, including:

  • muscle aches
  • fever
  • fatigue
  • headaches
  • dizziness
  • chills
  • abdominal issues (nausea, vomiting, diarrhea, and pain)

Later, people with HPS experience coughing and shortness of breath. In some cases, HPS is deadly.

In the United States, the most dangerous type of HPS comes from deer mice that carry the Sin Nombre virus. Other sources in the United States include the cotton rat, rice rat, and white-footed mouse.

Salmonellosis

Salmonellosis is a type of bacterial infection caused by Salmonella bacteria. These bacteria can live in the intestines of many animals, including rodents. Most commonly, salmonellosis causes:

  • diarrhea
  • stomach cramps
  • abdominal pain
  • fever

Symptoms last for 4 to 7 days.

Some people with Salmonella infection show no symptoms. Mild cases of salmonellosis tend to resolve on their own, but severe cases can be fatal if you don’t receive timely treatment.

Omsk hemorrhagic fever

People who live in Western Siberia, Kazakhstan, and Russia are at risk of contracting Omsk hemorrhagic fever from rodents and tick bites. Symptoms of this viral infection mimic the flu and include:

  • fever
  • headache
  • nausea
  • muscle pain
  • cough

Bleeding, rash, skin sensitivity, and encephalitis may also develop in the later stages.

The fatality rate of Omsk hemorrhagic fever is low compared with some other similar rodent-borne diseases. Still, Omsk hemorrhagic fever can cause long-term body changes, including:

Rat-bite fever and Haverhill fever

Some rodents across North America and Asia may carry bacteria that cause rat-bite fever and Haverhill fever. You can also get rat bite fever from the rodent’s urine or through bites or scratches.

Rat-bite fever can cause severe disease and organ system damage. Without timely treatment, it can be fatal in 10% of cases.

Symptoms usually appear within 3 to 10 days of contact with the bacteria. They include:

If you feel unwell or experience symptoms of fever, unusual bleeding, or weakness, contact a doctor. It’s especially urgent to get medical help if you’ve had recent interactions with rodents and their droppings.

A doctor will perform a physical examination, take your medical history, and probably perform various tests. Blood, urine, and other tests can help them arrive at a diagnosis and develop a treatment plan.

The best way to avoid illness from mouse droppings is to prevent mice and other rodents from entering your home, vehicle, or other space. You can do this by making sure these spaces are well sealed.

At home, keep your food and garbage contained. Make sure any potential rodent entryways are sealed. Regularly check under the hood of your vehicle for signs of rodent infestations, since that’s a common entry point.

If you notice rodent droppings in your home or vehicle, it’s important to clean them up right away. Start by opening doors and windows to ventilate the space.

Contaminated air is most likely to cause disease. Before you grab a broom and sweep up or vacuum the droppings, there are additional steps you need to take to stay safe.

Follow these steps to keep safe while cleaning up rodent urine and droppings:

  1. Put on a pair of rubber or plastic gloves and a face mask.
  2. Open windows and doors and let the air out for 30 minutes.
  3. Spray the droppings with a bleach solution or disinfectant until they appear very wet. Allow them to soak and sit for 5 minutes.
  4. Use paper towels to wipe up the droppings and cleaning products.
  5. Throw the paper towels away in a plastic bag within your trash can, and make sure the trash is disposed of quickly.
  6. Mop or sponge the area where you found the droppings with a disinfectant product. Clean all nearby hard surfaces, such as floors, countertops, drawers, and cabinets. For rugs and upholstery, use a commercial disinfectant, ideally with a commercial-grade steam cleaner or shampoo.
  7. Wash contaminated bedding, clothing, or stuffed animals with hot water and detergent. Dry them in the sun or on high in the dryer.
  8. For any contaminated items you can’t clean with a liquid disinfectant (such as books or papers), place them outdoors in sunlight for several hours. You may also place them in an indoor area free of rodents for at least 3 weeks.
  9. Set out traps to catch any rodents that may be living in your space. You can reuse snap traps, but take similar caution when handling dead rodents. Spray dead mice, rats, nesting materials, the trap, and the surrounding area with disinfectant before handling them with gloves. Dispose of them in a separate plastic bag in your trash.

Removing rodent droppings from within air ducts, walls, or other structural areas of your home is more complex. It’s also very challenging (and can be dangerous) to tackle a severe rodent infestation.

For these jobs, it’s best to hire a professional who has the proper protective equipment.

Rodents such as mice often seek out vehicles, buildings, yards, and other human spaces to stay warm, sheltered, and fed. Their proximity to humans puts us at risk of developing serious and potentially fatal illnesses.

If you find mouse droppings, it’s important to clean them properly and carefully. You can also prepare by guarding against future mouse visits or infestations.

If you suspect you’ve contracted a rodent-borne disease, call a doctor and schedule an appointment right away.