The prospect of infections spreading from animals to humans has become all too real with the onset of the current swine flu pandemic, and the threat of a bird flu still looming. But infections can jump the other way too. Decades before the world's media were gripped with panic over bird flu, humans transferred a disease to chickens and it has since caused a poultry pandemic right under our noses.
The infection in question is a familiar one - Staphylococcus aureus, a common human bacterium that's behind everything from mild skin infections to life-threatening MRSA. It causes chicken…