Bird flu (avian influenza)

Bird flu is caused by a type of influenza virus that rarely infects humans. But when bird flu does strike humans, it's often deadly. More than half the people who become infected with bird flu die of the disease.

In recent years, outbreaks of bird flu have occurred in Asia, Africa and parts of Europe. Most people who have developed symptoms of bird flu have had close contact with sick birds. In a few cases, bird flu has passed from one person to another.

Health officials worry that a global outbreak could occur if a bird flu virus mutates into a form that transmits more easily from person to person. Researchers are working on vaccines to help protect people from bird flu.

Symptoms

Signs and symptoms of bird flu typically begin within two to five days of infection. In most cases, they resemble those of conventional influenza, including:

1. Cough
2. Fever
3. Sore throat
4. Muscle aches

Some people also experience nausea, vomiting or diarrhea. And in a few cases, a mild eye infection (conjunctivitis) is the only indication of the disease.

When to see a doctor 
See your doctor immediately if you develop a fever, cough and body aches, and have recently traveled to a part of the world where bird flu occurs. Be sure to let your doctor know if you visited any farms or open-air markets.