| Disease
Fact Sheet Series:
Hantavirus is the name of a family of related viruses
that have virtually a worldwide distribution.
Who gets hantavirus
infection?
Anyone can become infected with hantavirus, but persons
who have exposure to rodents or to rodent-infested areas are at highest
risk of the infection.
Is hantavirus infection a
new disease?
No. Outbreaks of disease compatible with certain types
of hantavirus infection have been described in Europe and Asia since the
1930's. However, in the United States, there were no reports of acute
disease associated with hantavirus prior to 1993. In the spring of that
year, an outbreak of severe respiratory disease caused by a newly
recognized strain of hantavirus occurred in the southwestern USA. It is
now apparent that illnesses due to this strain occurred before the 1993
outbreak but were not recognized.
How is hantavirus infection acquired?
Rodents are the natural hosts for all known
hantaviruses, and the virus can be found in their urine, feces, and
saliva. Once these substances have dried, humans can become infected by
inhaling the dried materials as dust particles. This is the most common
way the infection is acquired in the USA. People can also become infected
by a rodent bite, and possibly by ingesting food or water contaminated by
rodents. There is no evidence that people can become infected from other
humans, other animals, or from biting insects.
What are the signs and symptoms of hantavirus
infection?
The kind of illness that the virus can cause in humans
varies with the different types of hantavirus. A strain of the virus found
in the USA can cause a severe illness known as hantavirus pulmonary
syndrome. This is the same strain of virus that caused the 1993
outbreak of respiratory disease in the Southwest. Patients with this
infection initially have some or all of the following signs and symptoms:
fever, body aches, headache, nausea, vomiting, diarrhea, and dry cough.
However, the main symptoms are shortness of breath and difficulty
breathing. Progression to respiratory failure (an inability to breathe)
can occur rapidly (typically about 4 days after the first symptoms
appear). This disease is fatal in about half of the patients who contract
it.
Hantavirus strains found in Asia and Europe can cause
human disease characterized by acute fever, bleeding, kidney failure, and
shock. Other strains are not known to cause human illness.
How is hantavirus infection
treated?
There is no specific treatment for persons with
hantavirus pulmonary syndrome. Intensive supportive care in a hospital is
currently the only known beneficial measure.
Is the hantavirus present in Wisconsin?
To date (January, 2001), only one human case of
hantavirus pulmonary syndrome has ever been reported in Wisconsin. A small
percentage of mice in Wisconsin have been found to have antibodies against
the hantavirus strain that causes hantavirus pulmonary syndrome. The risk
of acquiring this infection in the upper midwest is extremely low.
How can a person avoid exposure to hantavirus?
Exposure to hantavirus can be minimized by avoiding
contact with rodents and their droppings. The following precautions are
adapted from guidelines issued by the US Centers for Disease Control and
Prevention. If
rodents, their nests, or areas
contaminated with rodent droppings are encountered while carrying out
these measures, follow the recommendations in point #4 below regarding
cleanup / disinfection of rodents and contaminated areas. Note especially
the need to thoroughly wet contaminated material with a disinfectant and
the need to avoid stirring up dust which may be inhaled.
1.
Control
mice outside by reducing potential habitats and food sources near your
home.
-
Elevate
woodpiles, hay, and garbage cans off the ground (by using pallets, for
example) and locate them at least 100 feet from house.
-
Cut
tall grass and brush within 100 feet of the house
-
Haul
away junk cares, old tires, etc.
2.
Make your home less attractive for rodents by keeping your house
clean.
3. Prevent mice from entering your
home.
-
Seal any openings to your home larger than 1/4 inch
using metal screen, steel wool or cement.
-
Clear brush/grass from
around foundation.
-
Consider using metal roof flashing as a rodent
barrier around the base of wooden dwellings (height of 12 inches and
buried 6 inches in the soil).
4. Once the home has been secured from rodent
entry, trap and dispose of rodents in home, clean and disinfect
premises.
-
Before rodent elimination and cleanup is to be done in an
infested building, ventilate closed buildings or areas inside buildings by
opening doors and windows for at least 30 minutes. Use exhaust fans or cross
ventilation if possible, and leave the area until the airing-out period is
over.
-
Persons involved in clean up of rodent-contaminated areas
or disposal of rodent carcasses should wear rubber or plastic gloves.
-
Spray dead rodents, rodent
nests, droppings, or other items contaminated by rodents with a general
purpose commercial household disinfectant (a dilute bleach solution of 3-
tablespoons bleach added to 1- gallon water is also effective). Soak thoroughly
and place in a double plastic bag. Seal bags and dispose by burying it 2 to 3
feet deep or by burning. If you have regular trash pickup, dispose of sealed
bags in a garbage can with a tight-fitting lid.
-
After removing contaminated
material, mop floors, counters, drawers, etc. with a solution of water,
detergent, and disinfectant. Do not vacuum or sweep dry surfaces before
mopping, as this will generate dust which can be inhaled. Dirt floors can be
sprayed with disinfectant. Carpets can be disinfected with household
disinfectants or by commercial-grade steam cleaning or shampooing.
Contaminated bedding or clothing should be laundered with hot water and
detergent, then machine dried on high setting or hung in the sun to dry.
-
Use spring-loaded traps baited
with peanut butter to kill rodents. Commercial rodent poisons can be used only
if there is no chance that children or pets will be accidentally exposed.
Always follow the instructions on the specific product. Dispose of dead
rodents as outlined above.
-
When done, wash gloved hands in
a household disinfectant and then soap and water before removing gloves. After
removal, wash hands thoroughly in soap and water.
5. Campers should consider the following precautions:
-
Avoid contact with rodents, their nests, and burrows
as much as possible (e.g. pitch camp away from woodpiles) and avoid
cabins that are rodent infested until they have been properly cleaned
and disinfected.
-
If possible, avoid
sleeping on bare ground. Use a floored tent or camp cots and ground
cloth.
-
Keep food in rodent-proof containers and do not drink
untreated surface water.
For more information, contact your
Local
Public Health Department
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Last Revised: February 13, 2009
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