Ever read “Terminal Man?”
PANDEMIC by Daniel Kalla
“Bird viruses meet their human counterparts in the bloodstream of the swine, where they mix and mutate before spreading back into the human population. And a new flu is born.
...In an age when every single person in the world is connected by three commercial flights or fewer, a killer bug can travel much faster than the flu of 1919.”
http://www.fantasticfiction.co.uk/k/daniel-kalla/pandemic.htm