But if the workers are vaccinated against human influenza, he said, "they can't catch it, so you won't get reassortment."

The symptoms of human influenza were clearly described by Hippocrates roughly 2,400 years ago.

Ferrets are an important experimental animal model for human influenza, and have been used to study the 2009 H1N1 (swine flu) virus.

If transmission does cause human influenza, it is called zoonotic swine flu.

The last big deadly human influenza epidemic in the world was in 1918.

One increasingly worrying situation is the possible antigenic shift between avian influenza and human influenza.

Health officials worry that the avian strain may combine with human influenza to create a new virus.

Just like human influenza, even after receiving the vaccination, a dog can still contract mutated strains or less severe cases.

Some blamed bird flu and took their weakened children to a clinic in a nearby provincial city, where a medic diagnosed human influenza instead.

Large-scale sequencing of human influenza reveals the dynamic nature of viral genome evolution.