Report an inappropriate comment Mon Apr 27 05:40:26 BST 2009 by
Dann ALL strains of human influenza go through birds and pigs
before jumping hosts to infect humans. Most new influenza
strains come from asian countries, because farming practices
over there bring pigs and fowl into contact. The virus starts
off in birds, and occasionally learns to jump the 'species
barrier' to infect pigs. Pigs are physiologically very similar
to humans, so the jump from pigs to humans is much easier than
the one from birds to pigs was. Along the way the virus may pick
up genetic material from it's various hosts. Viruses were
working with recombinant DNA for millions (if not billions) of
years before human scientists starting messing around with it.