Rodent Droppings and Hantavirus: Don't Sweep or Vacuum

Mouse and rat droppings turn up in attics, garages, sheds, cabins, crawlspaces, storage rooms and vehicles, especially after they have been closed up for a while. The natural reaction is to grab a broom or vacuum. CDC specifically warns against that. This guide explains why and what to do instead.

What hantavirus is and how it spreads

Hantaviruses are a group of viruses carried by certain wild rodents. In the United States, the deer mouse is one of the most familiar carriers, along with some other species. Infected rodents shed the virus in their urine, droppings and saliva. According to CDC, people most commonly become infected when fresh urine, droppings or nesting materials are stirred up, releasing tiny droplets containing the virus into the air, where they are breathed in. Infection can also happen through bites, though this is less common.

Hantavirus infection can cause hantavirus pulmonary syndrome, a serious respiratory illness. It is uncommon, but because it can be severe, prevention matters. Rodent droppings can also carry other diseases, which is another reason to avoid stirring them up.

Why sweeping and vacuuming are a problem

CDC's cleanup guidance says plainly: do not vacuum or sweep rodent urine, droppings or nesting materials. Both actions can send virus-containing particles into the air. A household vacuum also pushes air out of its exhaust, spreading fine particles around the room, and can leave contamination inside the machine. Using a leaf blower or compressed air in a garage or shed has the same problem on a larger scale.

Air it out first

CDC recommends that before cleaning a home, cabin, shed or barn that has been closed up with signs of rodents, you open all doors and windows and leave the space for 30 minutes to let fresh air in. For vehicles, CDC recommends opening the hood, doors and trunk for 20 minutes. Stay out of the space while it airs out.

Light versus heavy contamination

CDC provides step-by-step guidance for homeowners dealing with light contamination, such as a few droppings in a kitchen drawer. It recommends wearing rubber or plastic gloves and using a wet cleaning method with disinfectant rather than dry methods. If you are handling a small amount yourself, follow CDC's current instructions directly rather than improvising.

Heavy infestations are different. CDC notes that heavy infestations call for special precautions, including full protective equipment such as coveralls, goggles and a respirator, and that workers hired to clean them should contact their local or state health department and occupational safety authorities. Signs of heavy contamination include:

• Droppings across large areas, in thick layers or in multiple rooms
• Many nests, or nests in insulation
• Strong urine odor
• Dead rodents
• Contamination in attics, crawlspaces, wall cavities or ductwork
• Buildings closed up for long periods, such as cabins, barns and vacant houses

What not to do

• Do not sweep, vacuum, dust or use a leaf blower on droppings or nests.
• Do not touch droppings, nests or dead rodents with bare hands.
• Do not start cleaning a closed-up space without airing it out first.
• Do not run heating or cooling systems that may have rodent contamination in the ducts before they are checked.
• Do not let children or pets play in affected areas.

Special locations

HVAC and ductwork

CDC advises contacting a professional pest control service if rodents have gotten into heating or cooling systems. Running a contaminated system can spread particles through the building.

Vehicles

Rodents often nest in engine compartments and cabin air filters of vehicles that sit unused. CDC recommends consulting a qualified mechanic for help with vehicle contamination after airing the vehicle out. See our guide on vehicle contamination.

Attics and insulation

Contaminated insulation is usually removed and replaced rather than cleaned. This is dusty work that calls for respiratory protection and containment.

Bird droppings

Accumulated bird and bat droppings in attics, barns, steeples and under bridges raise similar concerns about stirring up dust. Large accumulations can harbor fungi that cause respiratory illness when disturbed. The same principles apply: avoid dry sweeping, limit dust, use appropriate respiratory protection, and consider professional help for large accumulations.

Preventing a return

Cleanup without exclusion means the rodents come back. Seal gaps and holes where rodents enter, remove food sources, store food in sealed containers, keep woodpiles and clutter away from the building, and consider trapping. A pest control professional can help with exclusion.

Know the symptoms

If you develop flu-like symptoms such as fever and muscle aches, particularly if followed by coughing or shortness of breath, in the weeks after contact with rodents or their droppings, see a health care provider and tell them about the rodent exposure. CDC advises talking with a provider if you think a recent illness may be related to a rodent-borne disease.

After cleanup

Once droppings and nesting materials are removed and surfaces disinfected, items stored in the affected area may need attention. Hard items can be cleaned. Cardboard boxes, fabric and paper that rodents nested in or soiled are usually discarded. Replace any contaminated insulation, and check that entry points have been sealed before restocking the space.

Landlords, employers and agencies

Property managers and employers should not ask staff to clear heavy rodent contamination without appropriate training and protection. Respirator use at work falls under OSHA's Respiratory Protection standard, which requires a written program, medical evaluation, fit testing and training. Many organizations use a professional for heavy infestations.

When to call a professional

Call a professional for heavy or widespread droppings, nests in insulation or ductwork, dead rodents, strong odor, or any situation you are not comfortable handling with CDC's guidance. To discuss a situation, contact New Dawn Bio Restoration or call 615-914-0790, and please confirm availability for your location.

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