What is avian influenza?

Tim Uyeki  Medical Epidemiologist

When we talk about the bird flu, or avian influenza, we’re really talking about a disease that affects birds.  And this is to be distinguished from human infections with avian influenza A viruses.  Now avian influenza can be caused by many, many different kinds of avian influenza A viruses.  There are two classifications of these viruses, what we call low pathogenic, and highly pathogenic.  And the distinction between what is a low pathogenic virus, and what is a highly pathogenic virus, this is based upon the molecular biology of the virus, as well as the pathogenicity or I would, the way I would refer to that is, how much it kills birds.