HPS is a serious, often deadly, respiratory disease that has been
found mostly in rural areas of the western United States.
The disease is caused by a virus carried by rodents and passed on
to humans through exposure to urine, saliva, or droppings from
How common is HPS?
Fortunately, HPS is a relatively rare disease. See
HPS statistics in the United States since 1983 (when the
disease was first recognized). Since 1983 to September 19, 2006,
453 cases has been reported in the United States. Out of the 453
cases, 45 (about 10%) cases were in California residents.
Does HPS occur in San Mateo County?
Yes, infected mice are found on a regular basis during disease
surveys in San Mateo County. However, there have not been any
human cases reported from this county.
What kinds of rodents carry hantavirus?
Wild deer mice in the genus Peromyscus are the
primary carrier of the virus that causes HPS.
Deer mice are found in San Mateo. Since the types of mice that
carry a hantavirus are difficult to identify, all wild rodents
should be considered potentially infectious and should be
How is the virus spread?
People are exposed to hantavirus through the urine, saliva and
feces of wild mice. The virus becomes airborne when rodent
droppings or nests are stirred up, such as when a mouse infested
building is swept. People can also become infected by touching
the mouth or nose after handling contaminated materials or when
food items become contaminated with mouse droppings. A rodent’s
bite can also transmit the virus.
Hantavirus is not spread from person to person. You cannot become
infected by being near a person who has HPS. Pets are not known
to transmit the virus to people. The virus, which is able to
survive in the environment, can be killed by most household
disinfectants, such as Lysol, bleach, or alcohol.
The highest risk of contracting a hantavirus is from exposure to
air-borne droplets from rodent droppings or secretions. Most
cases have been acquired in rural and semi-rural settings where
deer mice commonly invade human dwellings. Activities which pose
the highest risk include:
Occupying or cleaning rodent-infested barns, sheds, or
Disturbing rodent-inhabited areas while hiking or camping
Living in or visiting areas where there has been an increase
in the rodent population
Working in enclosed spaces infested with rodents
How can I protect myself when I clean up?
It is important to avoid creating airborne particles of dust and
debris while cleaning. Creating airborne particles increase the
risk of contact with HPS.
Ventilate the affected area the night before cleanup by
opening doors and windows
Use rubber gloves and wear a half-mask air-purifying (or
negative-pressure) respirator with a high-efficiency particulate
air (HEPA) filter
Apply household disinfectants at a maximum recommended
concentration to dead rodents, rodent droppings, nests,
contaminated traps, and surrounding area and allow for at least
15 minutes contact time before removal
Clean the affected area with paper towels or a mop. DO NOT
SWEEP OR VACUUM.
Double bag the disinfectant-soaked rodent and clean-up
material (newspaper, paper towels, etc.) securely in plastic bags
Before removing gloves, wash gloved hands in disinfectant,
and then in soap and water. Thoroughly wash hands with soap and
water after removing the gloves. Dispose of gloves and clean-up
materials with other household waste.
Symptoms of HPS usually appear within two weeks of infection but
can appear as early as three days and as late as six weeks after
First symptoms are general flu-like
symptoms. However, the primary symptom of this
disease is difficulty in breathing, which is caused by fluid
build-up in the lungs and quickly progresses to an inability to
breathe. Symptoms also include fever (101ºF–104ºF),
headache, abdominal, joint, lower back pain, and sometimes nausea
If any combination of the symptoms described above, especially
difficulty in breathing, appear after direct or indirect exposure
to rodents, contact your doctor or public health clinic
immediately and be sure to mention your exposure to rodents.