Influenza (Flu): The Disease
What is influenza?
Influenza (the flu) is a contagious disease that is caused by the influenza
virus. It attacks the respiratory tract in humans (nose, throat, and lungs).
The flu is different from a cold. The flu usually comes on suddenly and
may include these symptoms: fever, headache, tiredness (can be extreme),
dry cough, sore throat, nasal congestion, body aches. These symptoms are
usually referred to as "flu-like symptoms."
Can anyone get the flu?
Anyone can get the flu, but the disease is more severe for some people. Most people who get the flu will recover in 1 to 2 weeks, but some people will develop life-threatening complications (such as pneumonia) as a result of the flu. Millions of people in the United States - about 10% to 20% of U.S. residents - will get the flu each year. An average of about 20,000
people per year in the United States die from the flu, and 114,000 per year
have to be admitted to the hospital as a result of influenza. Serious problems from flu can happen at any age. People > 65 years old, people of any age with chronic medical
conditions, and very young children are more likely to get complications
from flu. Pneumonia, bronchitis, and sinus and ear infections are three
examples of complications from flu. The flu can make chronic health problems
worse. For example, people with asthma may experience asthma attacks while
they have the flu, and people with chronic congestive heart failure may
have worsening of this condition that is triggered by the flu.
How is the influenza virus passed around?
The flu is spread, or transmitted, when a person who has the flu coughs,
sneezes, or speaks and sends flu virus into the air, and other people inhale
the virus. The virus enters the nose, throat, or lungs of a person and begins
to multiply, causing symptoms of the flu. Flu may, less often, be spread
when a person touches a surface that has flu viruses on it - a door handle,
for instance - and then touches his or her nose or mouth. The Flu Is Contagious. A person can spread the flu starting one day before they feel sick. Adults
can continue to pass the flu virus to others for another 3-7 days after
symptoms start. Children can pass the virus for longer than 7 days. Symptoms
start 1-4 days after the virus enters the body. Some persons can be infected
with the flu virus but have no symptoms. During this time, those persons
can still spread the virus to others.
How do you know if you have the flu?
Your respiratory illness might be the flu if you have sudden onset of body
aches, fever, and respiratory symptoms, and your illness occurs during November
through April (the usual flu season in the Northern Hemisphere). However,
during this time, other respiratory illnesses can cause similar symptoms
and flu can be caught at any time of the year. It is impossible to tell
for sure if you have the flu based on symptoms alone. Doctors can perform
tests to see if you have the flu if you are in the first few days of your illness.
What should you do if you get the flu?
- Take medication to relieve the symptoms of flu.
- Drink plenty of liquids
- Avoid using alcohol and tobacco.
- Rest
A virus causes influenza, so antibiotics (like penicillin) don't work to
cure it. Antiviral medications have been shown to decrease the severity of the illness and duration of symptoms by 1 - 1 1/2 days. These medications are primarily used for people at high risk for complications of influenza. High risk people are those with chronic diseases or are over age 65.
The best way to prevent the flu is to get an influenza vaccine
(flu shot) each fall, before flu season. Never give aspirin to children
or teenagers who have flu-like symptoms - and particularly fever - without
first speaking to your doctor. Giving aspirin to children and teenagers
who have influenza can cause a rare but serious illness called Reye syndrome.
Children or teenagers with the flu should get plenty of rest, drink lots
of liquids, and take medicines that contain no aspirin to relieve symptoms.
What is the myth of the "Stomach Flu"?
Many people use the term "stomach flu" to describe illnesses with
nausea, vomiting, or diarrhea that are not caused by the flu virus, but
can be caused by many different viruses, bacteria, or even parasites. However,
while vomiting, diarrhea, and being "sick to your stomach" can
sometimes be related to the flu - particularly in children - these problems
are rarely the main symptoms of influenza. The flu is a respiratory disease
and not a stomach or intestinal disease.
| IS IT A COLD OR IS IT THE FLU? |
| Common Symptoms |
Cold |
Flu |
| Fever |
Rare |
Characteristic, high (102°-104°F; lasts 3-4 days) |
| Headache |
Rare |
Prominent |
| General aches, pains |
Slight |
Usual; often severe |
| Fatigue, weakness |
Quite mild |
Can last up to 2-3 weeks |
| Extreme exhaustion |
Never |
Early and prominent |
| Stuffy nose |
Common |
Sometimes |
| Sneezing |
Usual |
Sometimes |
| Sore throat |
Common |
Sometimes |
| Chest discomfort, cough |
Mild to moderate; hacking cough |
Common; can become severe |
| Complications |
Sinus congestion or earache |
Bronchitis, pneumonia; can be life-threatening |
| Prevention |
No vaccine or preventive medications; handwashing, plenty of rest and
good nutrition will help prevent the common cold |
Annual vaccination; antiviral medicines--see your doctor |
| Treatment |
Only temporary relief of symptoms |
Antiviral medicines--see your doctor |
| From the National Institute of Allergy and Infectious Diseases
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