Monday, 26 March 2012

Public health issues related to industrial food animal production; A One Health approach to the leading cause of death in children


Beth Feingold, PhD, MPH, MESc, is the Pim Postdoctoral Fellow in Global Change in the Earth and Planetary Sciences Department at The Johns Hopkins University. She is interested in geography and health, particularly the impact of industrial food animal production, climate, land use change and city planning on public health. Her One Health talk focused on public health issues related to industrial food animal production.

Dr. Feingold wanted us to take home 3 messages from her talk: 1) Industrial food animal production poses a number of threats to public health in the forms of air pollution, water pollution, environmental justice issues, emerging pathogens, and antibiotic resistant bacteria, 2) There are many challenges to quantifying the nature and magnitude of these effects, and to balancing risks, and 3) A One Health approach could help mitigate environmental, veterinary and human health risks posed by the food animal production system.

Dr. Beth Feingold explains the One Health challenges associated with industrial food animal production.

She began her talk by the defining Animal Feeding Operations (AFO) and providing a historical basis for modern industrial food animal production. In the past few decades, AFOs in the United States have become concentrated into fewer, large-scale operations. These farming operations face challenges such as wide-scale antibiotic use to preserve animal health and animal waste management. AFOs are connected with their surrounding communities and have substantial impacts on environmental and public health. Air and water pollution affect the people throughout a region; documented health effects include respiratory symptoms, headaches, anxiety, depression, sleep problems, decreased quality of life, and bacterial infection. These issues are compounded when natural disasters cause the flooding of animal waste processing sites, polluting the water and spreading pathogens across a region. Farm workers, in particular, are exposed to pathogens through multiple pathways on a regular basis.

According to Dr. Feingold, there are 3 main challenges that we currently face. First, it is difficult to characterize the cumulative effect of chemical, microbial, social, and economic stressors in diverse populations. Second, the food animal production industry is difficult to penetrate for scientists, and the externalities of production place a disproportionate burden on rural communities. Third, institutional and political barriers make it difficult to monitor industry externalities and ensure accountability.

William K. Pan, PhD, MPH, is the Assistant Professor of Global Environmental Health in the Nicholas School of Environment at Duke University, an Affiliate with the Duke Global Health Institute, and an Associate at the Duke Population Research Institute. Dr. Pan is interested in expanding the scope of One Health to include more disciplinary lenses, especially to fields outside of human and veterinary medicine. His One Health talk focused on diarrheal disease as a leading cause of death in children, risk factors of diarrhea, and a comprehensive approach to prevention and control.

Dr. William Pan contends that a One Health approach to diarrheal disease in children should also take into account perspectives of city planners, demographers, and veterinarians.

Dr. Pan began his talk by outlining the etiology of diarrheal disease in young children. He presented a model of diarrhea, malnutrition, and enteric infection that showed how diarrhea and malnutrition led to a vicious cycle that increased susceptibility to opportunistic infections. There are a variety of causes of diarrhea and infectious agents of diarrhea include many strains of bacteria, viruses, parasitic protozoa, and parasitic worms. A systematic review showed that ETEC and V. cholerae O1/O139 were the leading cause of hospitalizations, while Salmonella, Shigella, and E. histolytica were the most frequently isolated pathogens in outpatient settings. There are multiple paths to pathogen exposure, such as poor sanitation and water quality, hygiene, food preparation, flooding, animal husbandry, and animal vectors. However, Dr. Pan is concerned that underlying determinants such as birth rates, population density, and the built environment are routinely ignored. He brought up a story to accompany a photograph he took on one of his research trips to South America. In a boat, we could see a mother nursing an infant, along with 5 more young children. Dr. Pan pointed out that cultural preferences (or necessities) for high birth rates and large families are a barrier to diarrheal disease control. He proposed that the WHO enteric disease prevention plan would benefit from a One Health approach that adds perspectives from city planners, demographers, and veterinarians.

Post authored by Patrick Yao Tang MPH candidate 2012, Department of Health Behavior and Health Education, Gillings School of Global Public Health, UNC Chapel Hill

Up Next (27 March 2012):
Emergence of a zoonotic tropical disease in the United States: visceral leishmaniasis
Christine Petersen, DVM, PhD, Assistant Professor of Veterinary Pathology at Iowa State University College of Veterinary Medicine