Quantifying Human Health Risks from Animal Antimicrobials

In 1969, the Joint Committee on the Use of Antibiotics in Animal Husbandry and Veterinary Medicine in the United Kingdom warned that uncontrolled use of similar antimicrobials in humans and food animals might promote the emergence of resistant strains of foodborne bacteria that could endanger human health and compromise the effectiveness of antimicrobial therapies in human patients (Swann 1969). The Animal Health Institute (AHI) and its member companies collaborated with Cox Associates, an operations research consulting company, to develop and apply new, practical, quantitative risk assessment (QRA) modeling methods to assess the previously impossible-to-quantify risks (and benefits) to human health from continued use of animal antimicrobials. We came to some surprising conclusions that were robust to many uncertainties. Among these were that antimicrobials that benefit animal health may benefit human health, while regulatory interventions that seek to reduce antimicrobial resistance in animals may unintentionally increase illness rates (and hence antimicrobial use and resistance rates) in humans. These new QRA models and methods enable industry and regulatory decision makers to quantify and compare the probable human health consequences of alternative animal antimicrobial use plans and to design more effective approaches to protect human and animal health.