The Dangers of Mouse Droppings in Your Home

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the dangers of mouse droppings in your home

Mouse droppings in your home are more than just an unsightly nuisance; they pose significant health risks that can affect your entire household. Mice are common invaders, especially in colder months, and their droppings can harbor dangerous pathogens.

Understanding the potential dangers of mouse droppings is crucial for maintaining a safe and healthy living environment. By recognizing the health risks, identifying and safely cleaning up droppings, and implementing effective prevention strategies, you can protect your home and family from the serious threats posed by these small but hazardous invaders.

Common Places Mouse Droppings Are Found


Mice often enter attics through small gaps and cracks in the roofline, vents, and eaves. They are excellent climbers and can scale walls to access these high points.

Mouse droppings in attics typically look like small, black grains of rice, about 1/8-1/4 inches long, with pointed ends. Fresh droppings are dark and moist, while older ones turn gray and dry out over time.


Basements offer easy access through foundation cracks, gaps around utility pipes, and poorly sealed windows and doors.

Droppings are often found along baseboards, near storage areas, and in dark corners. They are similar in appearance to those in attics but can be found in larger quantities due to their proximity to the ground and potential food sources.

Kitchens and Pantries

Mice are attracted to kitchens and pantries because of the abundant food sources. They can enter through small holes in walls, gaps under doors, and utility lines.

Mouse droppings in kitchens and pantries are commonly found inside cabinets, behind appliances, and around countertops’ edges. When fresh, they are usually black or dark brown and shiny, and moist. You might also notice gnaw marks on food packages.


Garages provide easy access through open doors, gaps under doors, and cracks in the foundation.

In garages, mouse droppings are often found near stored items, along walls, and in corners. They look similar to those found in other parts of the house, and you might also see signs of nesting materials like shredded paper or fabric.

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What Kind of Rodents Should I Be Aware of?

Rodent Location Diseases Carried
House Mouse Southern California


Hantavirus, Salmonellosis, Lymphocytic Choriomeningitis (LCM)
Norway Rat Southern California


Leptospirosis, Rat-Bite Fever, Hantavirus, Salmonellosis
Roof Rat Southern California


Leptospirosis, Murine Typhus, Rat-Bite Fever, Salmonellosis
Deer Mouse Southern California


Hantavirus, Lyme Disease
Western Harvest Mouse Southern California Hantavirus
California Vole Southern California Pague, Tularemia
Dusky-Footed Woodrat Southern California Hantavirus
Townsend’s Vole Seattle Pague, Tularemia
Pacific Jumping Mouse Seattle Hantavirus

Chances of Getting Sick From Mouse Droppings

You can get sick from mouse droppings. Even if you don’t see or touch the droppings, they are still a health risk. Mouse droppings can contaminate your home’s air, surfaces, and food, leading to various diseases.

Mouse droppings can carry a variety of harmful pathogens that can become airborne or contaminate surfaces and food. These pathogens can cause illnesses when inhaled, ingested, or contacted indirectly. The risk of disease transmission is not limited to direct contact with the droppings; simply being in an environment where droppings are present can be enough to make you sick.

Invisible Threats: How Rodent Droppings Spread Illness Indirectly

  • Airborne Particles: As mouse or other rodent droppings dry out, their molecular structure starts to break apart and release particles into the air. Inhaling these particles can lead to respiratory infections and other illnesses.
  • Contaminated Surfaces: Mice often defecate as they move, spreading droppings across various surfaces. Touching these surfaces and touching your face, food, or mouth can lead to ingesting harmful pathogens.
  • Food Contamination: Mice droppings can contaminate food and food preparation areas. Consuming contaminated food can result in gastrointestinal diseases.

Hantavirus Pulmonary Syndrome (HPS)

Hantavirus Pulmonary Syndrome (HPS) is a serious respiratory disease that affects humans infected with hantaviruses. It sometimes proves fatal, with a 38% mortality rate. People who have been in contact with rodents carrying hantaviruses or have come in contact with their saliva, urine, or feces are at risk for HPS.

Unlike other diseases that only affect the elderly or infirm, HPS can infect healthy people of any age. Some of the most common ways people become infected with HPS include:

  • Airborne Transmission: Stirring up rodent urine, feces, or nesting materials can cause particles or droplets to enter the air you breathe.
  • Contact: Touching mouse poop, urine, or saliva before touching your mouth or nose is another way scientists think many people contract the disease.
  • Contaminated Food: Eating food contaminated with the feces, saliva, or urine of an infected mouse or rat can cause someone to become sick.
  • Biting: Although rare, an infected rodent that bites someone will put them at risk for HPS.


Symptoms of HPS can develop anywhere between one and eight weeks after exposure to hantaviruses. The early signs of HPS that seem to be universal for infected people include:

  • Fever
  • Fatigue
  • Muscle aches

Some people experience some additional issues in the early stages of HPS, including:

  • Dizziness
  • Chills
  • Headaches
  • Nausea
  • Diarrhea
  • Vomiting
  • Abdominal pain

The late symptoms of HPS, coughing and difficulty breathing, indicate the disease is attacking the respiratory system. Those experiencing late-stage symptoms of HPS need to get to a hospital immediately. The earlier treatment begins, the more likely it will be successful.

Bubonic Plague

The bubonic plague, also known as the Black Death, was the disease responsible for wiping out nearly a third of Europe’s population between 1346 and 1352. While many commonly associate the disease with rats, mice can also carry and spread it since it transmits to humans through the bites of rodent fleas.

Many assume that the bubonic plague was wiped out and no longer exists. It’s nowhere near as prevalent as it was in the 1300s, but those who come in contact with wild rodents can still be at risk of exposure.


Within two to eight days after exposure to bubonic plague, those infected will experience the following symptoms:

  • Chills
  • Headache
  • Fever
  • Muscle ache
  • Fatigue
  • Swollen lymph nodes in the neck, groin, or armpit

Although the chances of contracting bubonic plague remain low today, the infection can still be fatal. Those with plague symptoms receive antibiotic treatment to reverse the effects.

Leptospirosis (Weil’s Disease)

Leptospirosis, called Weil’s disease, refers to a bacterial infection carried by rats, mice, cattle, dogs, and pigs. While you cannot contract leptospirosis through rodent droppings, the urine you may come in contact with while cleaning or sweeping droppings contains the disease.

People get Weil’s disease through contact with infected urine after being exposed to cuts or abrasions on their bodies. This bacterial infection can also enter the body through the eyes, nose, and mouth, so simply touching your face after touching rodent urine may cause the infection.


The signs of leptospirosis arrive shortly after infection and include the following:

  • Chills
  • High fever
  • Conjunctivitis
  • Headache
  • Joint pain
  • Muscle ache
  • Abdominal pain
  • Vomiting
  • Nausea
  • Diarrhea
  • Red eyes
  • Loss of appetite

Those contracting Weil’s disease receive antibiotics to kill the infection and pain medication for muscle aches, pains, or fever. Patients suffering from leptospirosis generally recover within one or two weeks.

Lymphocytic Choriomeningitis

Lymphocytic Choriomeningitis (LCM) is a disease spread through infection of the lymphocytic choriomeningitis virus (LCMV). This rodent-borne illness spreads primarily through infected house mice, with cases of LCMV reported throughout Europe, Australia, North America, South America, and Japan.

LCM transmission occurs when someone with exposed cuts or scrapes comes in contact with infected rodent urine, poop, or saliva. LCMV can also enter the body through the nose, mouth, or ocular cavities.


People infected with LCM usually experience an onset of symptoms between eight and thirteen days following exposure. The most common early-stage symptoms last about a week and include:

  • Headache
  • Muscle ache
  • Fever
  • Malaise
  • Nausea
  • Vomiting
  • Loss of appetite

Some less frequent symptoms experienced in the initial phase of LCM are:

  • Cough
  • Sore throat
  • Chest pain
  • Joint pain
  • Salivary gland pain
  • Testicular pain

After a brief recovery period, many people experience a second wave of illness, such as:

  • Meningitis: Severe headache, high fever, confusion, seizures, stiff neck, and light sensitivity
  • Encephalitis: Difficulty speaking, disorientation, seizures, personality changes, paralysis, loss of consciousness, and sensory issues
  • Meningoencephalitis: Inflammation of the brain and the membranes surrounding the brain and spinal cord

LCM is not a permanent ailment. Those infected receive treatment with anti-inflammatory medication like corticosteroids until the virus leaves the body. LCMV has caused an increase in fluid around the brain for some who contract the virus, requiring surgical draining to relieve pressure.

Salmonellosis (Salmonella)

Most people recognize salmonella as a food poisoning, but you can find the bacteria that causes it in mouse and rat feces. Most salmonella cases in the U.S. occur due to household rodent infestation. Humans contract salmonella after ingesting food or drinks contaminated with feces from an infected animal.


Those infected with salmonella begin to experience symptoms anywhere from six hours to six days following infection. The most common symptoms include:

  • Abdominal pain
  • Diarrhea
  • Fever
  • Chills
  • Dehydration
  • Loss of appetite.

Salmonella is not fatal, but the initial symptoms can become severe. Most symptoms will pass after a few hours, while it may take four to seven days to recover completely. Those suffering the effects of salmonella should drink plenty of fluids until symptoms dissipate.

Identifying Mouse Droppings

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Mouse droppings are small, dark, rice-shaped pellets. They measure about 1/8 to 1/4 inch long and typically have pointed ends. Fresh droppings are usually black and shiny, while older droppings turn gray and dry out over time.

To accurately identify mouse droppings, it is important to compare them with droppings from other common pests:

  1. Cockroach Droppings:
    1. Appearance: Cockroach droppings are smaller than mouse droppings, usually about 1/8 inch long, and have ridges running along their length. They resemble ground pepper or coffee grounds.
    2. Location: Often found near food sources, in kitchen cabinets, and behind appliances.
  2. Rat Droppings:
    1. Appearance: Rat droppings are larger than mouse droppings, about 3/4 inch long, and have a more oblong shape with blunt ends.
    2. Location: Found in basements, attics, and other areas where rats are active.
  3. Squirrel Droppings:
    1. Appearance: Similar in shape to mouse droppings but larger, usually about 3/8 inch long. They are also more oval-shaped and thicker.
    2. Location: Often found in attics, around bird feeders, and near trees.

How To Safely Cleanup Mouse Droppings

Proper cleanup of mouse droppings is crucial to avoid spreading diseases. Here are the safety precautions and a step-by-step guide for safely cleaning up mouse droppings:

Safety Precautions

  • Wear Gloves and Masks: Always wear rubber, latex, or vinyl gloves and a mask or respirator to avoid direct contact with droppings and to prevent inhaling harmful particles.
  • Use Disinfectants: Have a disinfectant spray or a bleach solution (1 part bleach to 10 parts water) ready for use.

Step-by-Step Cleanup Guide

  1. Ventilate the Area: Open windows and doors to ventilate the area for at least 30 minutes before starting the cleanup. This helps disperse any airborne particles and reduces the concentration of contaminants.
  2. Spray Droppings with Disinfectant: Thoroughly spray the droppings and the surrounding area with a disinfectant. Let the disinfectant sit for at least 5 minutes to kill any pathogens.
  3. Remove Droppings with Paper Towels: Use paper towels or disposable rags to pick up the droppings. Avoid sweeping or vacuuming, as this can cause particles to become airborne.
  4. Dispose of Droppings in a Sealed Plastic Bag: Place the used paper towels and droppings in a plastic bag and seal it tightly. Then, immediately dispose of the sealed bag in an outdoor trash can.
  5. Clean the Area with Disinfectant: After removing the droppings, clean the entire area with disinfectant to eliminate all contaminants.
  6. Wash Hands Thoroughly: After removing gloves, wash your hands thoroughly with soap and water to remove residual bacteria or viruses.

Professional Assistance

While these steps can help you safely clean up small amounts of mouse droppings, a professional pest control service should be contacted for larger infestations. Professionals can ensure proper cleaning and disposal of contaminated materials without spreading diseases.

Preventing Mouse Infestations

To effectively prevent mouse infestations, focusing on sealing entry points, proper food storage, and regular inspections and maintenance is essential.

Sealing Entry Points

Mice can squeeze through incredibly small openings, so it’s crucial to seal any gaps and holes in your home’s structure.

  • Inspect and Close Gaps: Examine walls, floors, and foundations for cracks or holes. Seal small holes with steel wool and caulk, and use lath screen, lath metal, cement, or hardware cloth for larger gaps.
  • Doors and Windows: Install door sweeps on exterior doors and repair damaged window screens.
  • Utility Lines and Vents: Ensure all vents, pipes, and utility lines entering your home are properly sealed. Use mesh screens to cover vents and gaps around pipes.

Proper Food Storage

Mice are attracted to easily accessible food sources. Proper food storage is essential to keep them at bay.

  • Sealed Containers: Store all food, including pet food, in airtight containers made of metal, glass, or thick plastic.
  • Regular Disposal: Dispose of garbage regularly and use trash cans with tight-fitting lids.
  • Cleanliness: Keep kitchen counters, floors, and food preparation areas clean. Immediately clean up spills and crumbs to avoid attracting mice.

Regular Inspections and Maintenance

Regular inspections and prompt maintenance can help detect early signs of rodent activity and prevent infestations.

  • Routine Inspections: Check for signs of mice, such as droppings, gnaw marks, and nesting materials. Pay special attention to attics, basements, kitchens, and garages.
  • Prompt Repairs: Address structural issues immediately, such as fixing holes, repairing damaged screens, and sealing gaps.
  • Professional Pest Control: Consider scheduling regular inspections with a professional pest control service, especially if you live in an area prone to rodent infestations.

Contact Attic Projects Today if You Suspect You Have a Mouse Infestation

If you suspect you have a mouse infestation, acting quickly to avoid health risks and structural damage to your home is crucial. Attic Projects offers comprehensive services to eliminate rodents, clean up droppings, and rodent-proof your attic and crawl spaces. Here’s how they can help:

  • Rodent Removal: Professional and humane removal of mice from your home.
  • Dropping Cleanup: Safe and thorough cleanup of mouse droppings to prevent the spread of diseases.
  • Inspection Services: Detailed inspection of your attic and crawl spaces to identify entry points and signs of infestation.
  • Rodent Proofing involves sealing gaps and holes, installing barriers, and taking preventive measures to ensure your attic and crawl spaces remain rodent-free.

Ensure your home is safe and healthy with professional rodent control and prevention services from Attic Projects.


  1. “Hantavirus Pulmonary Syndrome.” Mayo Clinic, Mayo Foundation for Medical Education and Research, Accessed 24 May 2024.
  2. “Plague.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 20 Apr. 2023, Accessed 24 May 2024.
  3. Accessed 24 May 2024.
  4. NHS Choices, NHS, Accessed 24 May 2024.
  5. “Salmonella Infection.” Mayo Clinic, Mayo Foundation for Medical Education and Research, Accessed 24 May 2024.
  6. “Preventing Hantavirus.” Centers for Disease Control and Prevention, Accessed 24 May 2024.

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