This document summarizes the updated recommendations
from the Centers for Disease Control and Prevention (CDC) for hantavirus
risk reduction for workers. The information is adapted from the Morbidity
and Mortality Weekly Report, July 26, 2002; Vol. 51; No. RR09.
Precautions for Workers Frequently Exposed to
Persons who frequently handle or are exposed to wild rodents are probably
at higher risk for hantavirus infection than the general public because
of the frequency of their exposures. Such persons include, but are not
limited to, wildlife specialists, maintenance workers, pest-control workers,
some custodial staff, and building and fire inspectors. Therefore, enhanced
precautions are warranted to protect them against hantavirus infection,
as described below.
- Workers in potentially high-risk settings should
be informed by their employers about hantavirus transmission and symptoms
of infection, and be given detailed guidance on prevention measures.
Determining the level of risk for HPS in each work setting is the responsibility
of the park. The Regional Public Health Consultant and Safety Officer
may be contacted for assistance, if necessary.
- Workers who develop a febrile or respiratory
illness within 45 days of the last potential exposure should immediately
seek medical attention and inform the attending physician of the potential
occupational risk of hantavirus infection.
- When removing rodents from traps or handling
rodents, workers should wear either a half-face, tight-seal, negative-pressure
respirator or a positive pressure PAPR (powered air-purifying respirator),
equipped with N-100 filters. Employees must be in compliance with NPS
Director's Order #50B and Reference Manual #50B for respiratory protection.
Requirements include medical clearance, and annual training and fit
testing for each approved respirator type.
- Workers should wear rubber, latex, vinyl, or
nitrile gloves when handling rodents or handling traps containing rodents.
Before removing the gloves, wash gloved hands in a disinfectant or chlorine
solution and then wash bare hands in soap and water.
- Mammalogists or wildlife biologists who handle
wild rodents for research or management purposes should refer to the
published safety guidelines available on CDC's website, All About Hantavirus
Precautions for Workers Having Potential Contact
Insufficient information is available to provide general recommendations
regarding risks and precautions for persons who work in occupations with
unpredictable or incidental contact with rodents or their nesting sites.
Examples of such occupations include archaeologists, natural resource
specialists, utility operators, curators, and certain construction workers.
Workers in these jobs may have to enter buildings and crawl spaces, or
might otherwise be exposed to sites or material that are potentially rodent-infested.
Recommendations for such circumstances must be made on a case-by-case
basis after the specific working environment has been assessed. The Regional
Public Health Consultant or the Safety Officer may be consulted as needed
to assist in the assessment. Determining the level of risk present and
implementing appropriate protective measures is the responsibility of
Areas with evidence of rodent activity (e.g., dead
rodents, nests, and excreta) should be thoroughly cleaned to reduce the
likelihood of exposure to hantavirus-infected materials. Cleanup procedures
must be performed in a manner that limits the potential for dirt or dust
from contaminated surfaces to become airborne. Recommendations are listed
in this report for cleaning up (1) rodent urine and droppings, and surfaces
potentially contaminated by rodents; and (2) dead rodents and rodent nests.
Cleanup of Rodent Urine, Droppings, and Contaminated
- During cleaning, wear rubber, latex, vinyl, or
- Spray rodent urine and droppings with a disinfectant
or chlorine solution until thoroughly soaked. (See Cleanup of Dead Rodents
and Rodent Nests.)
- To avoid generating potentially infectious aerosols,
do not vacuum or sweep rodent urine, droppings, or contaminated surfaces
until they have been disinfected.
- Use a paper towel to absorb the urine and pick
up the droppings. Place the paper towel in the garbage.
- After the rodent droppings and urine have been
removed, disinfect items that might have been contaminated by rodents
or their urine and droppings.
- Mop floors with a disinfectant or chlorine
- Disinfect countertops, cabinets, drawers,
and other durable surfaces with a disinfectant or chlorine solution.
- Spray dirt floors with a disinfectant or
- Disinfect carpets with a disinfectant or
with a commercial-grade steam cleaner or shampoo.
- Steam-clean or shampoo rugs and upholstered
- Launder potentially contaminated bedding
and clothing with hot water and detergent. Use rubber, latex, vinyl,
or nitrile gloves when handling contaminated laundry. Machine-dry
laundry on a high setting or hang it to air dry in the sun.
- Leave books, papers, and other items that
cannot be cleaned with a liquid disinfectant or thrown away, outdoors
in the sunlight for several hours, or in an indoor area free of
rodents for approximately 1 week before cleanup. After that time,
the virus should no longer be infectious. However, to further reduce
risk, wear rubber, latex, vinyl, or nitrile gloves and wipe the
items with a cloth moistened with disinfectant.
- Before removing the gloves, wash gloved
hands in a disinfectant or chlorine solution and then wash bare
hands in soap and water.
Cleanup of Dead Rodents and Rodent Nests
- Wear rubber, latex, vinyl, or nitrile gloves.
- In the western United States, use insect repellent
(containing DEET) on clothing, socks, and arms to reduce the risk of
fleabites that might transmit plague.
- Spray dead rodents and rodent nests with a disinfectant
or a chlorine solution, soaking them thoroughly. Wait 10 minutes before
disturbing to ensure inactivation of the virus.
- Place the dead rodent or nest in a plastic bag,
or remove the dead rodent from the trap and place it in a plastic bag.
When cleanup is complete (or when the bag is full), seal the bag, place
it into a second plastic bag, and seal the second bag. Dispose of the
material in the double bag by burning it or discarding it in a covered
trash can that is regularly emptied. Contact the local or state health
department concerning other appropriate disposal methods.
- Clean up the surrounding area as described in
"Cleanup of Rodent Urine and Droppings and Contaminated Surfaces."
Two types of disinfecting solutions are recommended to clean up rodent
- General-Purpose Household Disinfectant: Prepare
according to the label, if not prediluted. Almost any agent commercially
available in the United States is sufficient as long as the label states
that it is a disinfectant. Effective agents include those based on phenols,
quaternary ammonium compounds, and hypochlorite.
- Hypochlorite Solution: A chlorine solution,
freshly prepared by mixing 1½ cups of household bleach in 1 gallon
of water (or a 1:10 solution) can be used in place of a commercial disinfectant.
When using chlorine solution, avoid spilling the mixture on clothing
or other items that might be damaged by bleach. Wear rubber, latex,
vinyl, or nitrile gloves when preparing and using chlorine solutions.
Chlorine solutions should be prepared fresh daily.
Cleaning Sheds and Other Outbuildings
Before cleaning closed sheds and other outbuildings, ventilate the building
by opening doors and windows for at least 30 minutes. Use cross ventilation
if possible. Leave the area during the airing-out period. This airing
helps to remove infectious primary aerosols that might be created by hantavirus-infected
rodents. In substantially dirty or dusty environments, additional protective
clothing or equipment may be worn. Such equipment includes coveralls (disposable
when possible) and safety glasses or goggles, in addition to rubber, latex,
vinyl, or nitrile gloves. For recommendations regarding precautions for
cleanup of outbuildings with heavy rodent infestations, see below.
Recommendations for Cleaning Homes or Buildings
with Heavy Rodent Infestations
- Special precautions are indicated for cleaning
homes or buildings with heavy rodent infestations. A rodent infestation
is considered heavy if piles of feces or numerous nests or dead rodents
are observed. Persons cleaning these homes or buildings should contact
their Safety Officer or Public Health Consultant. These precautions
also can apply to vacant dwellings that have attracted rodents while
unoccupied and to dwellings and other structures that have been occupied
by persons with confirmed hantavirus infection. Workers who are either
hired specifically to perform the cleanup or asked to do so as part
of their work activities should receive a thorough orientation about
hantavirus transmission and disease symptoms and should be trained to
perform the required activities safely.
- If the building has been closed and unoccupied
for a long period (weeks or months), ventilate the building by opening
doors and windows for at least 30 minutes before beginning any work.
The ventilation helps to remove aerosolized virus inside the structure.
Use cross ventilation if possible. Leave the area during the airing-out
- Persons involved in the cleanup should wear coveralls
(disposable, if possible); rubber boots or disposable shoe covers; rubber,
latex, vinyl, or nitrile gloves; protective goggles; and an appropriate
respiratory protection device as detailed in "Precautions for Workers
Frequently Exposed to Rodents."
- Personal protective gear should be decontaminated
or safely disposed of upon removal at the end of the day. If the coveralls
are not disposable, they should be laundered on site. If no laundry
facilities are available, the coveralls should be immersed in liquid
disinfectant until they can be washed.
- Unless burned on site, all potentially infectious
waste material from cleanup operations should be double-bagged in durable
plastic bags and then discarded in a covered trash can that is regularly
emptied. Contact the local or state health department concerning other
appropriate disposal methods.
- Persons involved in the cleanup who develop a
febrile or respiratory illness within 45 days of the last potential
exposure should immediately seek medical attention and inform the attending
physician of the potential occupational risk of hantavirus infection.