Industrial Chicken Farming Spreads Campylobacter

Research published on July 27, 2026, in the Proceedings of the National Academy of Sciences by scientists from the Ineos Oxford Institute at the University of Oxford reveals that the global expansion of industrial chicken farming has increased the spread of Campylobacter bacteria by over 100 times. The global chicken population has surged seven-fold since the 1960s to reach approximately 31 billion birds, accounting for 70% of all bird biomass on Earth. This massive concentration creates ecological pathogen sponges that allow bacterial strains from wild birds to enter, circulate, and adapt within commercial flocks. Genomic analysis of nearly 2,800 Campylobacter samples collected across 30 countries between 1979 and 2024 shows that dense farming environments drive genetic changes supporting antimicrobial resistance, oxidative stress tolerance, metal acquisition, and motility. With previous studies linking 80% of human Campylobacter infections in Oxfordshire to poultry meat carrying antibiotic-resistant strains, understanding these evolutionary dynamics is crucial for mitigating future zoonotic disease risks and foodborne illness burdens.