There seems to be no end to the human contamination of the planet. Several weeks ago pigs in Minnesota where found to have swine flu. While swine flu in pigs is to be expected the surprise was the source of the outbreak – humans. Now as the world gets smaller and the human population larger researchers at The Roslin Institute at the University of Edinburgh have shown that a strain of bacteria jumped to chickens from humans.

Viruses have always had the ability to cross species after all the 1918 pandemic was a type of swine flu. This however is the first proof of bacterial infection crossing from humans to animals. The study identified a form of the bacteria Staphylococcus aureus in chickens and found that the bacteria originally came from humans about 40 years ago. This was just about the time of the switch to intensive poultry farming practices.

Staphylococcus aureus. (Credit: Agricultural Research Service / United States Department of Agriculture)