The flu (also called influenza) is a viral infection. It affects the respiratory system. It can cause mild-to-severe illness, and sometimes it can lead to death. The best way to avoid getting the flu is by being vaccinated every year.
- Avian Flu
- Pandemic (H1N1) 2009 Flu
The influenza virus causes the flu. Each winter, the virus spreads around the world. The strains are usually different from one year to the next. While less likely, it is possible to get the flu when it is not flu season.
The two main kinds of influenza virus are Type A
Someone infected with the virus may sneeze or cough. This releases droplets into the air. If you breathe in infected droplets, you can become infected. You can also become infected through touch. If you touch a contaminated surface, you may transfer the virus from your hand to your mouth or nose.
The flu (also called influenza) is a viral infection. It affects the respiratory system. It can cause mild-to-severe illness, and sometimes it can lead to death.
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The best way to avoid getting the flu is by being
The doctor will ask about your symptoms and medical history. Diagnosis of the flu is usually based on symptoms.
In some cases, your doctor may take samples from your nose or throat to confirm the diagnosis.
Factors that increase your chance of the flu include:
- Living or working in crowded conditions (such as, nursing homes, schools, military forces, daycare centers)
- Being physically or mentally disabled—people with disabilities may not be able to easily communicate their symptoms or may have trouble practicing preventive measures against the flu, putting them more at risk.
Certain groups of people are at a higher risk of developing complications from the flu. Risk factors for complications include:
- Children younger than five years old
- Being 65 years old and older
Having certain conditions, including chronic lung condition (such as
); cardiovascular disease; kidney, liver, neurological, blood, or metabolic condition (such as diabetes)
Having a suppressed immune system (such as
- Being pregnant during the flu season
Being younger than 18 years old and receiving long-term aspirin therapy (may be at risk for
- Living in nursing homes or other long-term care facilities
- Being American Indian/Alaska Native
If you have the flu, you might infect others one day before symptoms start and up to five days (sometimes more) after you become sick. This means you may be infecting others even before you know you are sick.
Symptoms usually start abruptly. They may include:
- High fever and chills
- Severe muscle aches
- Severe fatigue
Decreased appetite or other gastrointestinal symptoms like nausea, vomiting, and
(more common in children than adults)
- Runny nose, nasal congestion
- Sore throat
(can last for two or more weeks)
- Swollen lymph nodes in the neck
You may start to feel better in 7-10 days. However, you may still have a cough and feel tired.
Treatment may include: