What is avian influenza, or “bird flu”?
Like humans, birds have naturally occurring influenza (flu) viruses. There are numerous types of avian influenza viruses that are carried by wild bird species throughout the world. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, bird flu is very contagious among birds and can make some domesticated birds, including chickens, ducks and turkeys, very sick and even kill them.
Birds and other animals, including pigs, also contract and transmit influenza. Wild birds, in particular, are natural carriers of influenza A viruses. They have carried animal influenza viruses, with no apparent harm, for centuries. Migratory waterfowl (ducks, geese) are known to carry viruses of the H5 and H7 strains or subtypes. These viruses are usually in the low pathogenic form – in other words, they aren’t as deadly to birds as highly pathogenic strains. Currently, avian influenza H5N1 is circulating in South East Asian and parts of Europe, infecting many poultry populations and some humans. This strain is highly pathogenic, or highly deadly to birds, and has infected a limited number of people. There is no evidence this virus is transmitted from person to person.
A. It is a disease, caused by an influenza A virus, that occurs in bird species. The natural reservoirs for the virus are wild waterfowl and shorebirds, particularly ducks and geese. It usually is not deadly in wild birds. There are several strains, or types, of avian influenza virus. Public health officials and researchers keep track of the strains by giving them names with individual H and N designations, such as H5N1.
