Avian flu or 'Bird flu' is predominantly a disease in birds. There are several different types of bird flu, but the one that is causing current concern is a virulent (or highly pathogenic) form called H5N1.

While it has transmitted to people in Asia in very close proximity to birds (eg. poultry workers), the virus does not pass easily, and there is no relation between chickens with avian flu on a farm and a person getting flu in their home.

There is a theoretical risk of flu viruses mixing if people with seasonal flu also become infected with avian flu. This could cause pandemic flu if an influenza virus turns into a new strain that can spread easily between humans, and to which they do not have immunity.

The risk of a person catching bird flu is extremely low. Since December 2003, bird flu has resulted in 335 confirmed cases in humans in 12 countries (leading to 206 deaths), to 12 November 2007.
Source: Directgov

Further informaton:

• Guidance from DEFRA
• DEFRA Contingency Plan
• Department of Health
• Directgov
• NHS Choices