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

WaSH and One Health; Microbial impacts of animal agriculture on water quality and human health risks

Before he became the director of the Water Institute at the University of North Carolina at Chapel Hill in 2009, Dr. Jamie Bartram spent ten years at the World Health Organization coordinating water, sanitation, hygiene and health.  He has worked in about 40 developing and developed countries and describes himself as a “generalist” in water and health.

Dr. Bartram began his lecture by asking the audience for estimates on how much disease could be prevented by better managing water, sanitation and hygiene.  Estimates ranged greatly, reaching as high as 90%.  Although the correct answer was that “almost one tenth of the global disease burden could be prevented by improving water supply, sanitation, hygiene and management of water resources," we later learned that this is most likely an underestimation. 

Dr. Jamie Bartram, PhD (Professor, Department of Environmental Sciences & Engineering at UNC) discusses WaSH and One Health.

Water risk factors comprise a medium to transmit pathogens and toxic chemicals, services that contribute to disease prevention and conversely the absence of which increase diseases risk, the development of natural resources and ecosystems, and behaviors (far fewer people wash their hands after using the restroom than we would hope!).  The major causes of water-related morbidity and mortality include diarrhea, malnutrition and malnutrition-associated disease, drowning, malaria, intestinal infections, trachoma, and schistosomiasis.  Diarrhea and the consequences of diarrhea are responsible for 65% of the Disability-Adjusted Life Years (the sum of years of potential life lost due to premature mortality and the years of productive life lost due to disability).

Dr. Bartram’s other take home points were that 1) interventions to improve water safety are cost-effective, returning $3-$4 to each dollar invested; 2) policy goals such as the Millennium Development Goals are inadequately ambitious; and 3) multidisciplinary collaboration is necessary and water safety is in part the responsibility of health professionals.

The second speaker, Dr. Mark D. Sobsey, is a Kenan Distinguished Professor of Environmental Sciences and Engineering at the UNC Gillings School of Global Public Health.  Dr. Sobsey specializes in Environmental Health Microbiology and Water Sanitation and Hygiene.  His lecture focused on the human and environmental risks of waterborne pathogens associated with food animal production systems.

Dr. Mark Sobsey, MS, PhD (Professor, Department of Environmental Sciences & Engineering at UNC; Director, Environment Microbiology Laboratory at UNC) discusses the microbial impacts of animal agriculture on water quality and human health risks.

Food animals such as swine, poultry, and cattle are often fed antibiotics in their diet to fight pathogenic bacteria.  The use of antibiotics leads to the development and fecal excretion of high concentrations of both the antibiotic resistant bacteria and the antibiotics.  Dr. Sobsey explained the importance of managing the manure waste of these animals so that the bacteria, as well as other pathogens that infect the animals, do not contaminate ambient waters.  He presented evidence that these pathogens currently do infect ambient waters and that there presence might pose risks to human health such as waterborne outbreaks.

Dr. Sobsey’s presentation really emphasized the interconnectedness between humans, animals, and the environment as well as the value of One Health’s holistic approach to the prevention of disease and the maintenance of both animal and human health.

Post authored by Mary Key, A.B. (UNC Master’s in Public Health Candidate)

Up Next (20 March): 

                        A One Health approach to the leading cause of death in children

William Pan, PhD, Assistant Professor of Global Environmental Health at Duke

Public health issues related to industrial food animal production

                        Beth Feingold, MPH, PhD, Postdoctoral Fellow at Johns Hopkins University

The West Nile Virus Outbreak of 1999: A Compelling Argument for One Health

Dr. Tracey S. McNamara, DVM, DACVP (Professor of Pathology at Western University of Health Sciences College of Veterinary Medicine) presented a fascinating overview of the chronology of the response to the West Nile virus outbreak of 1999.  She highlighted the deficits present in our system of response, and brought to light the many yet-unanswered questions regarding how emerging zoonotic diseases are handled in the U.S.  A somewhat routine story of an emerging zoonotic disease outbreak took on new urgency and revealed conflicts when presented through the lens of the One Health concept.

Click here to view this presentation.

A graduate of the New York State College of Veterinary Medicine at Cornell University, Dr. McNamara was working as the Bronx Zoo’s senior zoo pathologist at the time of the West Nile virus outbreak.  She currently serves in leading a collaborative effort with Russian colleagues on the “Human-Animal Interface” project as part of the Nuclear Threat Initiative’s Global Health and Biosecurity program in DC.

Dr. McNamara detailed how the initial discovery of dead crows on the zoo grounds coincided with an outbreak of what was thought to be St. Louis encephalitis (SLE) in New York City.  Necropsy of the affected birds revealed gross findings consistent with meningoencephalitis, and subsequent histopathology, virology, electron microscopy and immunohistochemistry confirmed that the birds were infected with the flavivirus West Nile virus.  Several facts pointed to the possibility that citizens of New York were not suffering from SLE.  Populations of sentinel birds in the zoo, who should have been affected were the culprit SLE, were thriving.  It became apparent to Dr. McNamara that perhaps WNV was affecting zoo avians and people in New York.  If so, this would be the first time the US would be facing a rapidly spreading zoonotic disease that had crossed species’ boundaries.

During the course of trying to work across agencies and confirm the zoonotic outbreak, Dr. McNamara faced tremendous obstacles in resources, available information, and more importantly, cooperation between human and veterinary medicine.  It required her persistent, assertive approach to finally establish the link and to reveal that indeed, WNV was the cause of both avian and human infections and illness.

Dr. McNamara’s recounting of the challenges she faced in establishing the cause of the outbreak revealed the inefficiencies, gaps, and vulnerabilities in facing a zoonotic disease outbreak.  Ten years later, no clear contingency plan exists, yet zoonoses are three times more likely to be emerging than non-zoonotic diseases.  The WNV outbreak is the perfect story to illustrate the need for a One Health approach.

The session concluded with several salient questions for which there are as of yet no clear answers.  The U.S. faces vulnerabilities to bioterrorism that can be met with the concept of interface between medical, veterinary, public health, and environmental agencies working together.  The need for the One Health approach is evident.  What are needed now are the practical and consistent applications of that approach.  This was an excellent presentation that illustrated that interdisciplinary cooperation is imperative.

Post authored by Jennifer S. Huff, RN

Graduate Student, UNC MPH Public Health Leadership Program

Up next (13 Mar):  

WaSH and One Health 

Jamie Bartram, PhD, Professor Environmental Sciences & Engineering at UNC

Microbial impacts of animal agriculture on water quality and human health risks

Mark Sobsey, MS, PhD, Professor, Department of Environmental Sciences and Engineering, Director, Environmental Microbiology Laboratory at UNC