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Cabins, RVs and seasonal homes

Deer mice, the main U.S. carrier of hantavirus, often move into vacant cabins and outbuildings, so a place that has been closed up needs to be ventilated and cleaned the safe way before you use it.[3][4][6][12]

The short answer

  • A cabin, RV or seasonal home that sits empty is an easy place for mice to nest, and wasps, cluster flies and other insects move into its walls and eaves. Before you leave, seal gaps larger than 1/4 inch and take the food out. When you come back, air the place out before you clean, wet droppings with disinfectant instead of sweeping them, look for wasp nests before working near eaves and sheds, and check the beds for bed bugs if guests or renters have stayed there.[1][9][6][3][19][20][8][13]
  • Before closing up, seal every gap larger than 1/4 inch with steel wool, metal or concrete, and remove all food.[1][2][9]
  • When you return, open all doors and windows for 30 minutes before cleaning.[6][3]
  • Spray droppings and nests with 1 part bleach to 9 parts water and let them soak 5 minutes before wiping up; never sweep or vacuum them.[6][12][3]
  • See a doctor if you get fever, fatigue and muscle aches within 1 to 8 weeks of rodent contact, and mention the exposure.[4]

If someone may be poisoned

  • Hantavirus: see a doctor right away if you get fever, fatigue and muscle aches 1 to 8 weeks after cleaning up after rodents, and say you were exposed to rodents. Four to 10 days after the first symptoms, coughing and shortness of breath can follow. CDC says thirty-eight percent of people who develop breathing symptoms may die.[4]
  • Stings: hives or widespread itching, trouble breathing or swallowing, swelling of the face, throat or mouth, dizziness or a rapid pulse after a sting call for medical help immediately; don't wait to see if the symptoms go away.[18][17]

Pests of seasonal homes

Deer mouse showing its white belly and feet Deer Mouse Peromyscus species (shown: P. maniculatus) The deer mouse is a wild mouse with a white belly and a furred, two-toned tail that sometimes moves into cabins, sheds and homes. In the United States it spreads the most common hantavirus that causes hantavirus pulmonary syndrome (HPS), a severe and potentially deadly lung disease, so the droppings and nests it leaves need careful cleanup. House mouse on a rug, small and gray-brown with large ears House Mouse Mus musculus The house mouse is a small, adaptable rodent that lives close to people in homes, schools and food businesses, eating and contaminating food, gnawing wiring and carrying disease. Norway rats, stocky brown rats, at the edge of water Norway Rat Rattus norvegicus The Norway rat, also called the brown or sewer rat, is a large, burrowing rat found throughout the contiguous United States wherever people live. European paper wasp, a slender black-and-yellow wasp with orange-tipped antennae European Paper Wasp Polistes dominula Paper wasps hang open, umbrella-shaped paper nests under eaves and in sheltered spots; they are much less defensive than yellowjackets and rarely sting unless a nest is disturbed. Eastern yellowjacket worker, black with yellow bands, resting on white fabric Eastern Yellowjacket Vespula maculifrons The eastern yellowjacket is a native, ground-nesting yellowjacket common across the eastern US in lawns, woodlands, pastures and parks; it defends its nest aggressively and can sting repeatedly. German yellowjacket on small flowers, showing black spots along the sides of its yellow abdomen German Yellowjacket Vespula germanica The German yellowjacket is an invasive wasp from Eurasia that has spread across the northern US, displaces native yellowjackets and often nests in buildings. Cluster fly seen from above, showing golden hairs on the thorax Cluster Fly Pollenia species (e.g., P. rudis) Cluster flies gather on the sunny sides of buildings in fall to find places to overwinter and then appear indoors, often in large numbers, on warm days through winter and spring. They do not breed indoors. Multicolored Asian lady beetle, orange-red with black spots Multicolored Asian Lady Beetle Harmonia axyridis The multicolored Asian lady beetle is a beneficial aphid predator outdoors but becomes a nuisance when it flies to buildings in fall to overwinter and ends up indoors. Clemson and Colorado State extension both describe it as a valuable aphid predator on crops, trees and shrubs. Adult boxelder bug, black with red-orange lines, on a leaf Boxelder Bug Boisea trivittata Boxelder bugs feed mainly on the seeds of female boxelder trees and become a nuisance in fall, when large numbers gather on and around homes looking for a place to spend the winter. Indoors they can stain fabrics and smell when crushed, but they don't damage the structure and don't breed inside. Adult bed bug after a blood meal, seen from above Bed Bug Cimex lectularius Bed bugs are wingless, blood-feeding insects that feed on sleeping or resting people, mostly at night; they have resurged worldwide and now turn up even in the finest hotels. CDC says they turn up in five-star hotels and resorts, and how clean a place is does not determine whether bed bugs are present.

Closing up for the season

Deer mice often move into vacated homes, cabins and other buildings, where they nest, store food and damage upholstered furniture, mattresses, clothing and paper. They aren't common in towns unless large parks or fields are nearby, which is why rural cabins and outbuildings get them.[3]

CDC's checklist covers the places mice usually get in. Mice can fit through a hole the width of a pencil (1/4 inch).[9][1]

  • Sealing small gaps and cracks is the most effective protection against deer mice in houses, cabins and outbuildings.[3][5][9]
  • House mice squeeze under 1/4-inch gaps and through 3/8-inch openings; steel wool makes a good temporary plug but can rust, so use metal or concrete around pipes, vents and cables.[1]
  • Inside, look under and behind kitchen cabinets, in closet corners, around the fireplace, windows and doors, around pipes under sinks and to the water heater and furnace, around floor and dryer vents, and in the attic, basement or crawl space. Outside, look among the rafters, gables, eaves and soffits, at attic and crawl-space vents, and where electric, plumbing, cable and gas lines enter.[9]
  • Fill small holes with steel wool held in place with caulk or spray foam, and use hardware cloth, metal sheeting or cement for larger holes. Fix gaps in trailer skirting, and seal outbuildings and garages as well.[9]
  • Doors, windows, ventilation screens, and entrances to garages, attics, crawl spaces and basements should fit tightly; cover door and window edges with metal if mice gnaw them. Fit the chimney with a spark arrester, and use a self-closing flap on an outside dryer vent, but be careful screening dryer vents, because lint buildup can cause fires.[3]
  • Store any food that stays in thick plastic, glass or metal containers with tight lids.[7][9]
  • Keep grains and animal feed in thick plastic or metal containers with tight lids, dispose of trash regularly, and keep garbage in thick plastic or metal cans with tight lids.[9][11]
  • Outside, CDC says to keep woodpiles 100 feet or more from the house and at least one foot off the ground, keep grass and shrubs within 100 feet trimmed, and keep compost bins at least 100 feet away.[9][11]
  • Place snap traps along walls, behind objects and in dark corners, where mice travel and droppings show up.[1][10]
  • CDC recommends snap traps and advises against glue traps and live traps, which can scare rodents into urinating and raise your chance of getting sick. Keep traps and any bait out of reach of children and pets.[10]
  • CDC also says to check traps daily and get rid of dead rodents right away. A trap left set in an empty cabin may hold a dead mouse when you return: spray it and the trap with disinfectant and bag it as described below.[10][6]

Opening up

The most common hantavirus in the United States, the one that causes hantavirus pulmonary syndrome, is spread by the deer mouse. People catch it mainly by breathing in air after fresh urine, droppings or nesting material from an infected rodent are stirred up, which is why sweeping or vacuuming is the step to avoid. The virus can also get in through cuts or the eyes, nose or mouth.[4][5]

Once deer mice have infested a building, UC IPM says to avoid working or sleeping in those areas until the infestation is controlled and the area has been made safe. Washington's health department says not to sweep out an infested cabin, but to air it out and disinfect it before sleeping there.[3][12]

  • Ventilate for 30 minutes, wear rubber or plastic gloves, soak droppings, urine and nests with disinfectant, and wipe up with paper towels.[6][3][12]
  • How long to air it out: CDC says to open all doors and windows for 30 minutes and leave the area while it airs; UC IPM says at least 30 minutes and suggests an electric fan in windows and doorways where possible. New Mexico's health department says at least one hour for buildings, garages or basements that have been closed up.[6][3][11]
  • How long to soak: CDC says to wet droppings, urine and nests with bleach solution or disinfectant for 5 minutes or as the disinfectant label says. UC IPM and Washington's health department say 10 minutes before removing nests, mice and droppings. The bleach solution is the same in all three: 1 1/2 cups of household bleach in 1 gallon of water (1 part bleach to 9 parts water), made fresh.[6][3][12]
  • Wear rubber, latex, vinyl or nitrile gloves. Washington's health department notes that a dust mask may give some protection against dust but does not protect against viruses. Bleach can damage rugs and fabrics and irritate skin.[12][3]
  • Mop floors and wipe counters, cabinets and drawers with disinfectant; wash bedding and fabrics that mice reached in hot water.[6]
  • Shampoo rugs and upholstered furniture with a disinfectant or a steam cleaner. Move boxes of possibly contaminated items outside to a well-ventilated, sunny spot; throw away cardboard boxes with urine or droppings, and disinfect plastic, glass or metal containers.[6]
  • Bag exposed insulation that is soiled with urine or droppings. If rodents have been in the heating and cooling ducts, CDC says to call a professional rodent control service.[6]
  • Bag dead rodents after spraying them with disinfectant, and wash your hands after removing gloves.[6][12]
  • Fleas are common on rodents. CDC suggests putting an EPA-registered insect repellent such as DEET on clothing, shoes and hands before picking up dead rodents and nests.[6]

Wasp and yellowjacket nests

Paper wasps build open, many-celled paper nests under eaves. Yellowjackets nest in holes in the ground (often old rodent burrows), inside wall and ceiling voids, or in enclosed gray paper nests hung from eaves or trees, and some aerial nesters are extremely defensive.[19][18]

  • Timing: UC IPM says overwintering queens come out in late winter to early spring and start new nests when the weather warms; Penn State says new colonies start in late spring or early summer. Either way, a nest found when you open up in spring is small, and Penn State says dealing with it early is safer and easier than waiting until it grows.[19][17]
  • Last year's nest: in states with cold winters, colonies die off when the weather turns cold and the paper nest breaks down over the winter. UC IPM notes that in very mild winters, and in coastal California south of San Francisco, some yellowjacket colonies survive for several years and become quite large.[18][19]
  • A nest in a wall or attic: find where the wasps get inside the living space as well as the outside entrance, and seal or treat the inside opening first so you don't drive the colony indoors. Penn State shows German yellowjackets coming into a house from an attic nest through a bathroom exhaust fan.[17]
  • Dust insecticides are usually better than foams or liquids inside a structure, which can damage wood, drywall and wiring. A dead nest left in a wall can draw carpet beetles once the insecticide breaks down.[17]
  • For how to decide whether to leave a nest, call a professional or treat it yourself, see the wasp nest guide linked below.[17][18]

Cluster flies and other insects that winter in the walls

Cluster flies gather on the sunny sides of buildings in fall, crawl into attics and wall voids for the winter, and come out on warm days, often in large numbers at windows. They are not breeding inside, they don't damage the house, and Penn State says they are not known to carry diseases of medical importance, though they can leave small dark spots on windows and walls. Multicolored Asian lady beetles, western conifer seed bugs and boxelder bugs overwinter in buildings the same way.[20][21][23]

  • Keep them out before fall: seal cracks around windows, doors, siding, utility pipes, behind chimneys and under the fascia with good-quality silicone or silicone-latex caulk, repair screens, and screen attic and crawl-space vents. New Hampshire Extension says to have attic vents screened before September 10th there.[20][21][22][23]
  • Already inside: vacuum the sluggish flies, then take the vacuum bag outdoors so they can't crawl back out. Seal the openings they come through, usually gaps around baseboards, window and door trim, and ceiling exhaust fans or lights.[21][20][23]
  • Penn State advises against treating wall voids and attics with insecticide: dead flies in the walls can feed carpet beetles that then attack woolens and stored goods, and foggers or crack sprays don't stop more flies from coming out of the walls.[20]

Bed bugs from guests and renters

Bed bugs ride in on luggage, clothing, bedding and furniture, which makes them a particular problem where occupants change often: Kentucky names hotels and apartments, and UC IPM furnished apartments and dormitories. Leaving the house empty does not starve them out.[13][14][8]

  • How long they last without feeding: UC IPM says 20 to 400 days depending on temperature and humidity; Kentucky says about 1 to 4 months in a heated or cooled building, and up to a year or longer at 55°F or less. EPA says several months to a year, and CDC several months.[8][13][14][16]
  • Where to look: UC IPM says about 85% of bed bugs are found in or near the bed, so start with the mattress seams, box spring, bed frame and headboard, then upholstered chairs and sofas, nightstands and the edges of carpet and baseboards.[8][13]
  • If you rent the place out, EPA's advice for landlords applies: detailed inspections when tenants leave, written prevention guidelines for tenants, and quick reporting without blame, since blame makes people slow to report. Check whether local laws set reporting or response requirements.[15]
  • UC IPM advises managers of furnished rentals to train cleaning staff to recognize bed bug signs, launder bedding often, keep clutter down so rooms are easy to inspect, and seal cracks and crevices. Mattress encasements are especially useful where there are many beds.[8][13]
  • When traveling, check behind headboards and mattress seams for bed bugs, and inspect luggage when you get home.[8][13][14]
  • Back home, wash and dry travel clothes at the hottest settings the fabric allows (UC IPM). Kentucky says a dryer at medium-to-high heat for 10 to 20 minutes kills all life stages.[8][13]

RVs, campers and vehicles in storage

  • Rats gnaw the insulation on engine wiring, causing malfunctions and expensive repairs, and house mice also chew wires in vehicles. Before starting a vehicle that has sat idle, CDC says to air it out and inspect the air intakes and filters.[2][1][6]
  • CDC's steps for a car, truck or camper: open the hood, doors and trunk and let it air out for 20 minutes; wear plastic gloves and a long-sleeved shirt; disconnect the battery before inspecting the engine compartment. Don't vacuum or pressure-wash droppings until they have been soaked with disinfectant for 5 minutes or as the label says.[6]
  • If you find nesting material in the air intake, remove it and the air filter, and put in a new filter.[6]
  • Rodents get into the passenger compartment through ducting, rusted areas and cable conduit, so leave no food anywhere in the vehicle. UC IPM says a weighted car cover that touches the ground all around can discourage rodents from reaching the engine and chewing wires.[6][2]
  • Treat a camper like a cabin: seal openings, remove food, and use the same ventilate-and-disinfect steps if you find droppings.[1][6][5]

Common questions

How long should I air out a cabin before cleaning up mouse droppings?
CDC says at least 30 minutes with all doors and windows open, staying out while it airs. UC IPM also says at least 30 minutes, and New Mexico's health department says at least one hour for a building that has been closed up.[6][3][11]
Can I vacuum or sweep up mouse droppings?
No. Sweeping or vacuuming can put droplets containing the virus into the air. Soak droppings, urine and nests with disinfectant first, then wipe them up with paper towels.[6][12][11]
Will leaving the house empty all winter starve out bed bugs?
Not reliably. Kentucky Extension says they can last up to a year or longer at 55°F or less, and UC IPM gives 20 to 400 days depending on conditions.[13][8]
Is last year's wasp nest under the eaves still active?
Usually not in cold-winter areas: colonies die off when the weather turns cold, and new nests are started by queens in spring. In very mild winters, and in coastal California south of San Francisco, some yellowjacket colonies survive for several years.[18][19][17]

Photo credits

Sources

  1. University of California Statewide IPM Program, “House Mouse (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/house-mouse/ (accessed 2026-11-10)
  2. University of California Statewide IPM Program, “Rats (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/rats/ (accessed 2026-11-10)
  3. University of California Statewide IPM Program, “Pest Notes: Deer Mouse, Publication 74161 (June 2012).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pndeermouse.pdf (accessed 2026-11-10)
  4. Centers for Disease Control and Prevention, “About Hantavirus.” www.cdc.gov/hantavirus/about/index.html (accessed 2026-11-10)
  5. Centers for Disease Control and Prevention, “Hantavirus Prevention.” www.cdc.gov/hantavirus/prevention/index.html (accessed 2026-11-10)
  6. Centers for Disease Control and Prevention, “How to Clean Up After Rodents.” www.cdc.gov/healthy-pets/rodent-control/clean-up.html (accessed 2026-11-10)
  7. U.S. Centers for Disease Control and Prevention, “What to Do to Protect Yourself From Animals After a Disaster (reviewed August 26, 2026).” www.cdc.gov/natural-disasters/response/what-to-do-protect-yourself-from-animals-after-a-disaster.html (accessed 2026-11-10)
  8. University of California Statewide IPM Program, “Pest Notes: Bed Bugs, Publication 7454 (May 2013).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnbedbugs.pdf (accessed 2026-11-10)
  9. Centers for Disease Control and Prevention, “How to Seal Up to Prevent Rodents.” www.cdc.gov/healthy-pets/rodent-control/seal-up.html (accessed 2026-11-10)
  10. Centers for Disease Control and Prevention, “How to Trap Up to Remove Rodents.” www.cdc.gov/healthy-pets/rodent-control/trap-up.html (accessed 2026-11-10)
  11. New Mexico Department of Health, “Hantavirus Pulmonary Syndrome (FAQ fact sheet, March 2025).” www.nmhealth.org/publication/view/help/887/ (accessed 2026-11-10)
  12. Washington State Department of Health, “Hantavirus.” doh.wa.gov/you-and-your-family/illness-and-disease-z/hantavirus (accessed 2026-11-10)
  13. University of Kentucky Entomology, “ENTFACT-636: Bed Bugs.” entomology.mgcafe.uky.edu/ef636 (accessed 2026-11-10)
  14. U.S. Environmental Protection Agency, “Protecting Your Home from Bed Bugs.” www.epa.gov/bedbugs/protecting-your-home-bed-bugs (accessed 2026-11-10)
  15. U.S. Environmental Protection Agency, “What Landlords Need to Know about Bed Bugs.” www.epa.gov/bedbugs/what-landlords-need-know-about-bed-bugs (accessed 2026-11-10)
  16. Centers for Disease Control and Prevention, “About Bed Bugs.” www.cdc.gov/bed-bugs/about/index.html (accessed 2026-11-10)
  17. Penn State Extension, “Getting Rid of Paper Wasps, Yellowjackets, and Other Stinging Insects (Jamie Kopco).” extension.psu.edu/getting-rid-of-paper-wasps-yellowjackets-and-other-stinging-insects (accessed 2026-11-10)
  18. University of Kentucky Entomology, “ENTFACT-620: Controlling Wasps, Hornets, and Yellowjackets (M. F. Potter).” entomology.mgcafe.uky.edu/ef620 (accessed 2026-11-10)
  19. University of California Statewide IPM Program, “Yellowjackets and Other Social Wasps (Home and Landscape).” ipm.ucanr.edu/home-and-landscape/yellowjackets-and-other-social-wasps/ (accessed 2026-11-10)
  20. Penn State Extension, “Cluster Flies.” extension.psu.edu/cluster-flies (accessed 2026-11-10)
  21. University of New Hampshire Cooperative Extension, “Cluster Flies [fact sheet] (A. Eaton and R. Maccini).” extension.unh.edu/resource/cluster-flies-fact-sheet (accessed 2026-11-10)
  22. Washington State University Extension, “Cluster flies (Pestsense).” pestsense.cahnrs.wsu.edu/?p=1161 (accessed 2026-11-10)
  23. Clemson Cooperative Extension Home & Garden Information Center, “Cluster Flies.” hgic.clemson.edu/factsheet/cluster-flies/ (accessed 2026-11-10)

Updated 2026-11-10. Built from sourced records. Spot an error? Tell us.