|Image of Deer Mouse taken from CDC|
I read in the paper the other day that seven Yosemite visitors have recently been stricken with Hantavirus. Three died. Hantaviruses are found in the droppings, urine and saliva of infected deer mice. Hantavirus pulmonary syndrome (HPS), the illness caused by the virus, can take 3 to 60 days to develop after exposure. Symptoms include fever, headache, muscle aches, vomiting and diarrhea. The syndrome is fatal in 30%-40% of all cases. There is no vaccine, treatment or cure for HPS. Hantavirus is typically transmitted by breathing in particles in the air from the droppings, urine and saliva of infected rodents. However, there have been a small number of reported cases of HPS believed to have been contracted through rodent bites. Since the virus was first identified in the United States in 1993, there have been 67 cases in California and 593 nationwide including along the Appalachian Trail possibly in Virginia. Rodents, themselves, neither get sick nor can they pass along the infection to other animals; however the Center for Disease Control, CDC, has identified the ability of Hantavirus to adapt to new rodent species. Although currently rare, HPS is potentially deadly and may be an emerging disease. Rodent control in and around the home (and Curry Village) remains the primary strategy for preventing Hantavirus infection.
Knowing about Hantavirus, I was distressed and disgusted upon returning from an extended trip in the first year we owned our home to discover mouse droppings in the pantry and utility room. My husband took care of the capture and removal and I took care of the safe cleanup and mouse proofing the house, while the cat provided monitoring, patrolling the house at night. The only comments I have on mouse capture is that peanut butter and walnuts are excellent bait for either the capture and release traps or the spring traps. It appears that mice love nuts and the ruined baking supplies provided excellent bait for my husband’s trapping. It took a while, but eventually the husband was able to rid the house of mice. Though at one point it seemed he would dump the mouse in the woods and it would sneak right back in through the gas pipe in the fireplace. Eventually, I managed to seal up all likely entries and we have been mouse free for a while, but annual maintenance is necessary to keep mice out of the house.
A mouse can fit through the narrowest gap, seemingly flattening themselves to crawl into the house. According to the Center for Disease Control a gap of a quarter of an inch or a hole the size of a pencil eraser is large enough for a mouse to enter. A systematic approach is best for sealing all entry points. First of all, there is no way to prevent mice from getting into the garage because garage doors just do not seal that tight in their tracks. Instead, it is necessary to keep all nesting material and clutter out of the garage and seal all entries to the house. If you keep your trash cans in the garage make sure that the can(s) has a tight lid and no holes in the can. The garage turned out to be an area of entry into our house. Because of a sloping lot that gives me a daylight basement, the top of the foundation is about 12 inches above the garage floor. A compressed layer of insulation had allowed the mice entry into the basement. Steel wool and lath screening was pushed into every crack, the area caulked and thanks to Larry Reed, carpenter extraordinaire, the garage was finished, trimmed and sealed. New weather stripping was placed on every exterior door. Lath screen was cut to fit around all the kitchen pipes, the dryer vent pipe, the gas pipe to the fireplace the pilot light and valve to the fireplace. The space between the foundation and siding was carefully caulked and sealed. Attic vents were screened. Windows were caulked and weather stripping on the windows checked. All exterior holes for electrical, plumbing, and gas lines were carefully sealed with Duxseal.
Do not sweep or vacuum up mouse urine, droppings, or nests. This will cause virus particles to go into the air, where they can be breathed in. To clean up the mouse dropping and my pantry, and utility room I first geared up. According to OSHA and the CDC if there is not a heavy accumulation of droppings you need only wear disposable protective clothing and gloves (neoprene, nitrile or latex-free), rubber boots and a disposable N95 respiratorto safely clean up rodent droppings. A N95 disposable respirator is just one of those white dust masks (look for the certification number and yes, I keep them in the house), I wore my rain boots and some old work cloths that I threw out afterwards. The first thing I did was throw out all the food in the pantry and sprayed the shelf paper with disinfectant. Make sure you get the urine and droppings very wet. Let it soak for 5 minutes and then use paper towel to wipe up the urine and droppings and throw the paper towels into a plastic bag and seal carefully. I also removed the shelf paper and then cleaned the pantry again using disinfectant.
In the utility room I sprayed the floor and all flat surfaces including furnace ducts, modem shelf and top of the furnace, hot water heater and pressure tank with disinfectant, let it soak in for five minutes then used paper towels to wipe up all the droppings and then used a disposable swifter wet mop to mop the room. The basement was never cleaner. After cleanup is complete and all paper towels and swifter pads sealed in plastic bags, wash you gloved hands and boots with spray a disinfectant or a bleach solution before taking the gloves and boots off. Then throw the gloves out along with the clothes. Wash hands with soap and warm water after taking off your gloves and take a nice hot shower before going to the store to buy new shelf paper and pantry staples. While at the store buy heavy plastic canisters to store grains, and baking supplies.