The Web site of the U.S. Centers for Disease Control and Prevention (CDC) provides answers to questions about numerous health topics. The following are questions and answers about bird flu.
What is avian influenza (bird flu)?
Avian influenza is an infection caused by avian (bird) influenza (flu) viruses. These flu viruses occur naturally among birds. Wild birds worldwide carry the viruses in their intestines but usually do not get sick from them. However, avian influenza is very contagious among birds and can make some domesticated birds, including chickens, ducks and turkeys, severely sick and kill them.
Infected birds shed influenza virus in their saliva, nasal secretions and feces.
How do people become infected?
Most cases of bird flu infection in humans have resulted from direct or close contact with infected poultry, such as domesticated chickens, ducks and turkeys, or surfaces contaminated with secretions and excretions from infected birds.
The spread of avian influenza viruses from an ill person to another person has been reported very rarely, and transmission has not been observed to continue beyond one person. During an outbreak of avian influenza among poultry, there is a possible risk to people who have direct or close contact with infected birds or with surfaces that have been contaminated with secretions and excretions from infected birds.