Avian flu is caused by a type of influenza virus that rarely infects humans. More than a dozen types of avian flu have been identified, including the two strains that most recently infected humans – H5N1 and H7N9. When bird flu hits people, it can be fatal.
Avian influenza outbreaks have occurred in Asia, Africa, North America and parts of Europe. Most people who have developed bird flu symptoms have had close contact with sick birds. In some cases, avian flu has passed from person to person. Only sporadic human cases have been reported since 2015.
The signs and symptoms of bird flu can appear within two to seven days of infection, depending on the type. For the most part, they are similar to those of conventional flu, including:
Avian influenza occurs naturally in wild waterfowl and can be transmitted to domestic fowl such as chickens, turkeys, ducks, and geese. The disease is spread through contact with the feces of an infected bird or secretions from the nose, mouth, or eyes.
Outdoor markets selling eggs and birds in crowded and unsanitary conditions are breeding grounds for infection and can spread disease throughout the community.
The greatest risk factor for avian flu appears to be contact with sick birds or with surfaces contaminated with feathers, saliva, or feces. The model of human transmission remains a mystery. In very rare cases, bird flu has been transmitted from person to person. But unless the virus spreads more easily among humans, infected birds pose the greatest danger.
People with avian flu can develop life-threatening complications, including:
Pink eye (conjunctivitis)
Bird flu vaccine
The Food and Drug Administration has approved a vaccine to prevent infection with a strain of the H5N1 avian flu virus. This vaccine is not publicly available, but in the US it is stored by the government and distributed in the event of an epidemic.