A potentially fatal infection in birds caused by any of various subtypes of the influenza virus, especially the H5N1 virus, which is highly contagious among birds and can be transmitted to humans who have been in direct contact with infected birds.
American Heritage Medicine
Avian Flu Sentence Examples
Until relatively recently avian flu was thought only to infect birds.
There is every reason to believe that SARS and now avian flu will be followed by other public health challenges.
The current level of risk to human health posed by H7 avian flu is very low.
However, Intervet claims these excretions would not be large enough spread avian flu.
They are unlikely to be carrying avian flu but they can suffer from other infections that people can catch.