Guidance for cleaning and disinfecting vehicles with rodent infestations

Rodents, including squirrels, mice, and rats, may build their nests in cars, trucks, campers, and other vehicles. This is more likely if vehicles aren't used often.

Rodent nesting materials can be found in many areas of a vehicle, including:

• The engine compartment, including in engine compartment insulation
• The ducting and air filtration components of a vehicle's heating and air conditioning system
• The trunk of a car, including the spare tire compartment
• The passenger compartment, including the headliner, glovebox, and in or under the seats
• Tool compartments
• Taillight and headlight access areas and enclosures

Some rodents, such as deer mice, can carry hantavirus. Their nesting materials, droppings, and urine may contain hantavirus. People cleaning or riding in the car may be in contact with these infected materials. Infectious virus particles may blow onto passengers through the air vents, creating a risk.

Rodents can enter vehicles through:

• Rust holes
• Wire chases
• Side vents
• Rocker panels
• Ducting

Nesting materials in the air intake system of a vehicle can also cause odors inside the passenger compartment. This could weaken engine performance, prevent the vehicle from starting, or cause it to run poorly. These problems may also be caused by electrical wires and cables that the rodents have chewed on.

Inspecting and removing infectious nesting materials from a vehicle

Engine compartment

While the car is in open air, open the hood to allow the engine compartment to air out for 20 minutes. Also, open vehicle doors and the trunk to air it out. Wearing plastic gloves and a long-sleeve shirt, inspect the engine compartment for evidence of nest building. Nesting materials could be anywhere, but are commonly between the battery and vehicle frame, near the windshield wiper motors. Another common place is underneath air intake ducting or within the air filter.

Areas of the vehicle with evidence of rodent activity should be thoroughly disinfected to reduce any exposure to hantavirus-infected materials. Evidence would be presence of dead rodents, droppings, or nesting materials.

Do not use a vacuum cleaner or sweep rodent urine, droppings, or contaminated surfaces until they have been disinfected. Otherwise, this could cause potentially infectious aerosols. Also, do not use ‘power wash' high-pressure sprayers to soak or dislodge nests or droppings.

Nesting materials within automotive air intake systems

Rodents may move through the vehicle's air intake system. They may build nests on top of accordion-style air filters or in hoses and ducting that leads directly to the passenger compartment. For engine compartment air filters, open the unit to reveal the filter. If you see evidence of rodent activity, spray as above using either a commercially labeled disinfectant or a mixture of 1 part bleach to 9 parts water. Spray the materials until fully soaked and let sit 5 minutes. Or, follow the manufacturer's instructions for dilution and disinfection time. Then, remove both the nesting materials and the air filter and discard in the garbage. Insert the new replacement filter and close the unit.

If the rodent infestation is extensive, you may need to replace hoses, ductwork, filters, fans, or other components of the system. In this case you should have qualified mechanics or automotive professionals do the inspection and clean up. Tell the mechanic of the potential for hantavirus.

Passenger compartment

Rodents can enter the passenger compartment through rusted areas, ducting, areas where cabling passes, and the trunk. A variety of approaches can help seal out holes and cracks where rodents can enter. Do not leave food of any kind in the car, as it can attract rodents.

Trunk

Rodents can enter the trunk from holes in the body, through cable conduits, and from the back seats in certain vehicles. A variety of approaches can help seal out holes and cracks where rodents can enter. Do not leave food of any kind in the car, as it can attract rodents.

After inspection and cleaning

Before removing your gloves: 

• Rinse your gloved hands with disinfectant.
• Empty the remaining disinfectant in the garbage bag with the disposed material.
• Seal the bag.
• Rinse your gloved hands with water, remove your gloves, and finish by washing your hands with soap and water.

Prevention of nesting in vehicles

Regular exterior and interior inspections of a vehicle will help prevent infestations in vehicles. You can do this whether the vehicle is in regular use, abandoned, garaged, or otherwise stationary. Snap traps and poison baits are effective in stopping rodent access into vehicles. When starting a vehicle that has been idle for an extended period, air it out first and inspect the air intake and filters before starting the engine.