| Disease
Fact Sheet Series:
What is influenza?
Influenza or
"flu" is a respiratory disease caused by two main types of
influenza virus – type A and type B. It is a seasonal illness that
occurs each winter in Wisconsin
and throughout the United States. It is not a reportable disease in Wisconsin, and the annual number of cases is unknown.
How
is influenza spread?
Influenza
is spread from person to person when droplets of moisture from a person
with influenza are spread through the air when that person coughs, sneezes
or talks. These droplets contain viruses that when inhaled by another
person can cause an infection.
How soon do symptoms appear?
Symptoms
appear typically 1 to 3 days after exposure to respiratory droplets from
an infected person.
What are the symptoms of influenza?
Influenza
illness ranges from very mild to severe, depending on such factors as the
influenza strain involved, and the person's susceptibility and general
physical condition. Symptoms include fever, chills, headache, dry cough,
and aching in the muscles and joints. Most people recover within a week
after they become ill, although they may continue to feel tired for
several days. Influenza can last longer and cause life-threatening
complications in elderly persons, persons with chronic medical conditions
such as diabetes, heart, lung, or kidney disease, severe anemia, or
chronic diseases that weaken the immune system including persons with HIV
or AIDS infection.
How long is an infected person able to spread
influenza?
An infected
person can spread influenza virus in discharges from their nose and throat
from 24 hours before the onset of their illness to 3-5 days after onset of
illness. Young children and persons with a weakened immune system can
spread the virus for 7 days or longer.
How is influenza diagnosed?
Usually the
diagnosis is based on the appearance of specific signs and symptoms of
influenza. Confirmation can be achieved through laboratory testing of
throat specimens or blood samples.
How is influenza treated?
Certain
anti-viral drugs available with a physician’s prescription may reduce
the severity of disease caused by influenza if therapy is started early in
the course of the illness (within 48 hours of the beginning of symptoms).
Otherwise, bed rest, drinking increased amounts of liquids, and taking
pain relievers to help reduce the discomfort of illness is recommended.
Children with influenza should not be treated with aspirin due to the risk
of developing Reye’s syndrome.
When should persons at high risk of developing
complications due to influenza, receive influenza vaccine?
The best
time to vaccinate persons who are at high risk of complications from
influenza, is during October and November.
Is there any other way to prevent influenza other
than vaccination?
Yes, certain
drugs may help to prevent influenza in high-risk persons or their
caregivers who need protection during an influenza outbreak, but who have
not been vaccinated. A physician should be consulted about the use of
these drugs.
For more information, contact your
Local
Public Health Department
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Last Revised: November 04, 2008
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