Although bird flu is an animal illness which affects all species of wild or domestic birds as well as other animal species, in exceptional circumstances the bird flu virus can also be transmitted from animals to humans.
The bird flu virus is transmitted from animals to humans by air, essentially when there are close, prolonged and repeated contacts in confined spaces with the respiratory secretions or excrement of infected animals, or by exposure to contaminated surfaces or materials. Exposure occurs above all in the slaughtering, plucking, butchering and preparation of poultry prior to cooking.
In the European Union, where contact with animals is generally not as close as in Asia, no case of transmission of the H5N1 virus to humans has yet been diagnosed.
The current subtype H5N1 of the bird flu virus is not very infectious to humans: out of millions of people who have been in close contact with infected birds, especially in Asia, there have been 650 cases of human infection so far, of which 386 have resulted in death. The first documented cases of transmission from animals to humans date back to 1997 in Hong Kong. For updated figures please consult the list of confirmed human cases of bird flu by the World Health Organisation.
(State of knowledge as at 24.1.2014)