Links between industrial livestock production, disease including zoonoses and antimicrobial resistance

A range of studies indicates that keeping farm animals in crowded, stressful conditions leads to an increased risk of the emergence, transmission, and amplification of pathogens including zoonoses. Some such zoonoses could lead to a pandemic. Biosecurity, though essential, is not on its own sufficient to prevent the entry of disease into large, intensive livestock housing. To minimize disease risks, both biosecurity measures and the keeping of animals in conditions that are supportive of good health and effective immunocompetence are necessary. A further threat to human health arises from the routine use of antimicrobials in intensive livestock production to prevent disease. This high use of antimicrobials contributes significantly to the emergence of antimicrobial resistance in animals, which can then be transferred to people, thereby undermining the efficacy of the antimicrobials that are so important in human medicine. If we want to save our antimicrobials and minimize the risk of future zoonoses and pandemics, we need to move to “health-oriented systems” for the rearing of animals, systems in which good health is inherent in the farming methods rather than being dependent on the routine use of antimicrobials. Health-oriented systems should avoid high stocking densities and large group size, should minimize stress and mixing of animals, and ensure that animals can perform their natural behaviors as the inability to do so is highly stressful. They should avoid the use of animals selected for excessive production levels as these appear to involve an increased risk of immunological problems and pathologies.