Globalisation and industrialisation are causing diseases to spread from humans to animals, a University study has shown.
Researchers from The Roslin Institute and the Centre for Infectious Disease have shown that a strain of bacteria has jumped from humans to chickens.
It is thought to be the first clear evidence of bacterial pathogens crossing from humans to animals and spreading since the domestication of animals around 10,000 years ago.
The study identified a form of the bacteria Staphylococcus aureus - of which MRSA is a subtype - in chickens.
The researchers then found that the bacteria originally came from humans.
Genetic testing showed that the bacteria crossed over from one species to another around 40 years ago.
This coincides with a move towards intensive poultry farming practices.
“The demand for meat has led to a poultry industry dominated by a few multinational companies which supply a limited number of breeding lines to a global market - thereby promoting the spread of the bacteria around the world.”
Staphylococcus aureus bacteria are a major cause of animal diseases, including bone infections in poultry.
Unlike the corresponding form of in humans, which was isolated to one geographical area, the strain in chickens was spread across different continents.
If bacteria are also shown to be crossing over from humans to other livestock then there could be an impact on food security.
Infectious diseases in chicken flocks are a major economic burden on the industry.
The spread of bacteria from humans to chickens could have a huge impact on poultry farming.
Further research will look at analysing other livestock for emerging pathogens and diseases that may have come from humans.
The study was was published in the Proceedings of the National Academy of Sciences.
It was funded by the Biotechnology and Biological Sciences Research Council, which included a PhD studentship for first author Bethan Lowder.
Photo credit: Norrie Russell, The Roslin Institute.