MODEL RELEASED. Bird flu. Conceptual image of a chick being held by a human hand. This could represent human control of the bird flu virus or the preparation of birds for vaccination, quaratine or culling. The deadly H5N1 strain of the disease first appeared in 2003 in South-East Asia, and has spread rapidly, being detected in Africa, Asia and most of mainland Europe by early 2006. It is fatal to poultry and several other birds, and can be carried by many more bird species. It is also fatal to humans in some cases, and had been responsible for nearly 100 human deaths by early 2006. Measures to control its spread include vaccination of vulnerable birds, bringing the birds inside, or culling them in the path of the disease.