A highly contagious among chickens, ducks, and turkeys, bird flu is an infection caused by naturally occurring viruses in the species. Human cases of the disease are rare, but are becoming more prevalent in Asian countries. Vaccines to protect humans against the H5N1 strain of bird flu are currently under development, as is research to make large quantities of vaccine more quickly.
Avian influenza -- commonly called "bird flu" or "avian flu" -- is an infection caused by influenza viruses that occur naturally in birds. Wild birds can carry the bird flu viruses, but usually do not get sick from them. However, some domesticated birds, including chickens, ducks, and turkeys, can become infected with the avian flu virus and die.
(Click Avian Flu Virus for more information about the bird flu.)
Wild birds often carry the bird flu virus in their intestines, but usually do not get sick from it. Bird flu is highly contagious among birds and can make some domesticated birds, including chickens, ducks, and turkeys, very sick and even kill them.
Infected birds shed bird flu virus in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with contaminated secretions or excretions or with surfaces that are contaminated with secretions or excretions from infected birds. Domesticated birds may become infected with bird flu virus through:
- Direct contact with infected waterfowl or other infected poultry
- Contact with surfaces (such as dirt or cages)
- Materials (such as water or feed) that have been contaminated with the virus.