Friday, 18 March 2011

Intensive Swine Production: Antimicrobial Resistance and the Health Impacts of Air Pollution

Dr. Sid Thakur and Dr. Steve Wing shared their expertise on intensive swine production with the One Health Intellectual Exchange this past Wednesday, March 15th. Dr. Thakur, Assistant Professor in the College of Veterinary Medicine at NC State University, started the evening with a talk on antimicrobial resistance as it relates to the swine industry. Afterwards, Dr. Wing, Associate Professor of Epidemiology at the UNC School of Public Health, presented a different perspective, and spoke about the health impacts of air pollution associated with intensive pig farming. These topics are of particular interest in North Carolina. This state houses more pigs than humans, and is responsible for 14.4% of the total hogs produced in the United States.

In true One Health spirit, Dr. Thakur touched upon the three dimensions of antimicrobial resistance (human, animal, and environmental), but focused primarily on the role of the environment, which has been ignored in many discussions on this topic. In the environment, resistance can potentially be transferred from water, soil, feed, waste lagoons, and transport vehicles.

His presentation demonstrated the need for further studies that focus on One Health and the environment, and the importance of judicious use of antibiotics. Recent developments in the field have shown that soil microbes are resistant to practically all antibiotics, and resistant bacterial strains have a higher fitness than susceptible strains in the absence of antibiotics. Dr. Thakur’s research found that resistant Campylobacter strains were present in comparable levels for anti-microbial free systems and conventional systems in sampled pigs and carcasses in North Carolina. He also confirmed that transport trucks can play a role in the dissemination of antimicrobial resistance in swine production systems.

Dr. Wing’s presentation switched our talk’s focus to the potential impacts of intensive swine production on human health. He cited numerous cross-sectional studies that show people living in close proximity to industrialized swine operations have increased prevalence of respiratory and psychological conditions, and a lower quality of life. With swine operations in North Carolina primarily located in communities of color, this is an issue of environmental injustice.

For an epidemiological study examining the community health effects of industrialized hog operations, Dr. Wing partnered with environmental justice organizations in North Carolina to study acute health effects. He found an association between hog pollutants and physical symptoms.

Some of the questions raised by students, professors, and professionals regarding these topics included:

  • How can policies to protect humans from adverse health effects associated with intensive swine production be implemented?
  • Why is there not a larger environmental injustice movement to change health disparities?
  • Do areas such as North Carolina, with a proportionally larger number of CAFOs than other states, have higher rates of antibiotic resistance in human infections?
  • Has there been validation of clinical or epidemiologically relevant transmission of antibiotic resistant strains of bacteria between environmental reservoirs or animal livestock to humans?
  • What are possible theories as to why swine from antimicrobial free farms were still found to contain pathogens that showed resistance to antibiotics?
  • What is the role of wild animal populations in the transmission of resistance?

Thank you to Dr. Thakur and Wing for engaging and informative presentations that sparked interesting discussions on intensive swine production and how it relates to One Health!