WHAT IS MY RISK OF GETTING HPS?

For most Californians, the risk of gettingHPS is extremely low. Fewer than 50 casesof HPS have been diagnosed in California inthe last 10 years. Rodents in homes orbuildings in an urban or suburbancommunity are likely not deer mice buthouse mice or roof rats, neither of whichcarries hantavirus. Symptoms such as fever,headache, muscle pain, and shortness ofbreath are common to many differentillnesses and are more likely to be due tosomething other than hantavirus infection.Any concerns you have about your health orpossible exposure to hantavirus should bediscussed with your health care provider.For information about HPS and rodents inyour community, contact your local healthdepartment or vector control district.

Published by the State of CaliforniaDepartment of Health ServicesVector-Borne Disease Section1616 Capitol Ave, MS 7307

P. O. Box 997413Sacramento, CA 95899-7413

(916) 552-9730

Arnold Schwarzenegger, Governor

S. Kimberley Belshé, Secretary Sandra Shewry, DirectorHealth and Human Services Agency Department of Health Services

April 2005

FACTS ABOUT

HANTAVIRUSIN CALIFORNIA

Hantavirus pulmonary syndrome is a rare

but frequently fatal illness that occurs

throughout the western United States,

including California. By familiarizing

yourself with how hantavirus is transmitted

and by taking appropriate precautions, you

can prevent infection in yourself and family.

WHAT IS

“HANTAVIRUS PULMONARY SYNDROME”?

Hantavirus pulmonary syndrome, or HPS, is arare but often severe disease which is associatedwith rodents. Rodents which are infected withhantavirus shed the virus in their urine,droppings, and saliva. People can becomeinfected if they breathe in virus particles thathave been stirred up into the air.

SYMPTOMS OF HPS

The first symptoms of HPS begin about 1-5weeks after exposure and resemble the flu:fever, headache, and muscle aches.

After 2-5 days, HPS patients develop difficultybreathing. Breathing problems are often severethe HPS patient may need to be hospitalized forintensive care. There is no specific treatment forHPS. Approximately 25% of HPS patientsdiagnosed in California have died. Persons withHPS cannot give it to someone else.

HANTAVIRUS IN NATURE

Hantavirus is carried by wild rodents. InCalifornia, only one rodent species is known tocarry hantavirus: the deer mouse (scientificname, Peromyscus maniculatus). Deer mice aresimilar in size to house mice (4-7 inches) but,unlike house mice, are grey to brown on top andwhite underneath, and have large unfurred ears.

Deer mice can be found in most undevelopedareas throughout the state. They prefer brush,shrubs, and rocks, but will enter homes andbuildings for food, shelter, and nesting material.Not all deer mice carry hantavirus and theproportion of infected mice varies throughoutthe state. Infected deer mice appear healthy andnormal. It is also difficult to tell deer mice fromother kinds of rodents that don’t carryhantavirus. Therefore, persons should avoidcontact with all rodents.

Dogs, cats, birds, insects, and other animalscannot serve as a source of hantavirus infection.

TRANSMISSION OF HANTAVIRUS

People can get HPS when they have contactwith infected deer mice or materialscontaminated with deer mouse droppings orurine. Infection usually occurs throughbreathing in particles of infectious rodentdroppings or urine that have been stirred upinto the air. Failure to wash hands afterhandling rodents or rodent-contaminatedmaterials may also lead to infection.

Examples of activities that pose a risk ofhantavirus infection include:

< Entering sheds, cabins, barns, or otherbuildings where rodents are present

< Cleaning or working in enclosed,poorly ventilated spaces contaminatedby rodents

< Handling live or dead rodents withoutgloves

< Disturbing or cleaning up rodent nestsor droppings

PREVENTION OF HANTAVIRUS INFECTION

Infection with hantavirus can be prevented bykeeping rodents out of homes and otherbuildings and cleaning contaminated areas in asafe manner.

Cleaning areas contaminated by rodentsDead rodents, rodent nests, and droppingsshould be removed and surfaces cleaned beforeareas are reused.

Before entering or cleaning potentiallycontaminated areas, open windows and doors and allow the area to air out for 1-2 hours.

Wear latex or rubber gloves. Painters’, dust, andsurgical masks do not provide adequateprotection against hantavirus.

Wet down rodentcarcasses, traps, nests,and other potentiallycontaminated items andsurfaces with dilutebleach or disinfectant. Amixture of 1½ cups ofbleach or Lysol® in agallon of water iseffective at killing thevirus.

Allow dampened areas to sit for 15 minutes thenclean up with a mop or sponge. Do not vacuumor sweep. Contaminated items that cannot bedisinfected (e.g., paper, wood, fabric) should becarefully set outside for 2-3 days to allowsunlight to inactivate the virus.

When done, rinse gloves in bleach or Lysol®solution before removing. Remove gloves,dispose in garbage, and thoroughly wash handswith soap and water.

Removing rodents from homesPlace spring-loaded “snap” traps alongbaseboards and in areas where rodents areentering the home.

Do not use glue or live traps as these mayincrease your risk of infection. Place traps nearareas of rodent activity, but out of the reach ofpets and children. Examine traps regularly andremove trapped rodents promptly. Dispose ofpotentially contaminated traps or thoroughlydisinfect them prior to reuse.

Place rodent carcasses, traps, and othercontaminated items in a plastic bag. Tie off thebag, place inside a second bag and tie thesecond bag as well. Dispose of bags with othergarbage.

Keeping rodents out of homesCheck buildings regularly for signs of rodents;look for live or dead mice, droppings, urinestains, nests, and gnawing marks. Look forholes or gaps inside and outside the building.Inside, check within and behind kitchencabinets, inside closets, around vents, behindappliances, around windows and doors, aroundall electrical, water, gas, and sewer lines.Outside, look around windows and doors,between the foundation and the ground,between the foundation and the siding, aroundelectrical lines and water pipes, and in eavesand vents in the roof.

Seal all holes that arelarger than 1/4 inch indiameter. Use cement,wire screening, hardwarecloth, or steel wool.Reinforce the sealingmaterial with caulk orexpanding foam.

Reducing attractions for rodentsThe following measures can reduce the risk ofrodents in and around homes:

< Place woodpiles, vegetable gardens,trash cans, and pet food at least 100 feetfrom the house.

< Promptly remove uneaten pet food.

< Keep food in tightly sealed containers.

< Fix leaks in sprinklers or other outsidepipes that might attract rodents as awater source.

< Keep garbage in tightly sealedcontainers and dispose of at leastweekly.