Industrial poultry farming drives Campylobacter spread

A new scientific study has found that the massive global expansion of industrial poultry farming has dramatically accelerated the spread and evolution of Campylobacter, the world's most common bacterial cause of diarrhoea. The research, published in the Proceedings of the National Academy of Sciences, indicates that the movement of Campylobacter strains between wild birds and chickens has increased more than a hundredfold, creating ideal conditions for the bacteria to mix, spread, and acquire dangerous new traits, including antimicrobial resistance.

The study, conducted by researchers at the University of Oxford's Ineos Oxford Institute, analysed nearly 2,800 bacterial genomes collected from chickens and wild birds in 30 countries between 1979 and 2024. It links the surge in bacterial exchange directly to the scale of modern chicken production. Since the 1960s, the global chicken population has increased sevenfold, reaching approximately 31 billion birds. Chickens now account for about 70 percent of all bird biomass on Earth.

While this expansion has enabled the production of affordable animal protein, it has also fundamentally altered the ecology of pathogens. The researchers...