Avian influenza A(H5N1): Symptoms and treatment

Avian influenza A(H5N1) is also known as bird flu or avian flu. It's a contagious viral infection that mainly affects birds, but can sometimes infect other animals and humans.

On this page

• Symptoms of A(H5N1)
• If you become ill
• Diagnosing A(H5N1)
• Treating A(H5N1)

Symptoms of A(H5N1)

A(H5N1) is rare in humans. Some people with A(H5N1) don't have any symptoms at all. Illness can range from mild to very severe. Symptoms usually start to appear 1 to 5 days after exposure, but can also appear later.

Symptoms often start with:

• cough
• shortness of breath
• fever
• aching muscles
• headache

Other early symptoms may include:

• diarrhea
• runny nose
• sore throat
• fatigue
• red eyes (also known as pink eye or conjunctivitis)
• bleeding gums

In rare cases, A(H5N1) may progress quickly to:

• severe respiratory illness, which can include:
• difficulty breathing
• pneumonia
• severe and sudden respiratory failure (acute respiratory distress syndrome)
• neurological changes (changed mental state or seizures)

In severe cases, A(H5N1) may also lead to:

• multi-organ failure, which can include:
  • kidney and liver dysfunction
  • heart failure
• death

If you become ill

Isolate yourself by staying home and limiting your contact with others (including animals) in your household. Use personal protective measures to avoid spreading it to others.

Contact a health care provider or your local public health authority immediately if you develop symptoms of A(H5N1) and had close contact with:

• birds, other animals or people that have (or may have) A(H5N1) in the 10 days before symptom development or
• places where A(H5N1) has recently been found

Depending on your situation, a health care provider may recommend testing or early antiviral treatment. If treatment is needed, it's important to receive it as soon as possible, ideally within 48 hours of getting sick.

Monitor your symptoms while you're ill. If you have severe symptoms, or your symptoms get worse, call 9-1-1 or your local emergency number immediately. Tell them you may have been exposed to avian influenza. Follow their instructions to avoid spreading it to others.

Learn more:

• Avian influenza A(H5N1): Who is most at risk
• Avian influenza A(H5N1): Prevention of human-to-human spread
• Respiratory infectious diseases: What personal protective measures to use

Diagnosing A(H5N1)

A laboratory test is needed to diagnose A(H5N1). Usually, a health care provider will take a swab from your nose or throat. They will send this swab to a laboratory for testing. This will identify the virus that's causing your illness.

Treating A(H5N1)

Antiviral medications can be used to treat A(H5N1). It's important that you take these medications as soon as possible, ideally within 48 hours of getting sick. They can:

• reduce your symptoms
• shorten the length of your illness
• reduce serious complications

People with severe A(H5N1) may need to be treated in hospital.