Below are some of the many scientific reports detailing the problems associated with Concentrated Animal Feeding Operations
NC Hog CAFO Science Studies
1. 1995 -- A 1995 study reviewed the effect of odors emanating from large-scale hog operations on neighbors. The results indicated that persons living near the swine operations experienced odors and reported significantly more tension, depression, anger, fatigue, and confusion. Persons exposed to the odors also had more total mood disturbance.
2. 1996 -- Studies from 1996 and later reflected that swine CAFOs were disproportionately located in communities of color and poverty and thus among populations more susceptible to the exposures and more likely to experience detrimental health consequences.
3. 1997 -- A 1997 study of neighbors living within a two-mile radius of a 4,000 sow swine facility found that they reported higher rates of toxic or inflammatory respiratory effects. The configuration of respiratory symptoms among neighbors was consistent with the patterns of respiratory health problems among swine confinement workers.
4. 1997 -- A 1997 study assessing air quality around swine sites showed concentrations of hydrogen sulfide and ammonia that exceeded U.S. Environmental Protection Agency and Agency for Toxic Substances and Disease Registry recommendations.
5. 1998 -- A 1998 study showed how odor can have a deleterious health effect, including a physiological pathway between the olfactory lobe and the immune system which directly implicate odor as a health risk.
6. 1999 -- A 1999 report listed that health effects of swine sites included “odors; waste; resulting flies; poor air quality; and the contamination of drinking water supplies.”
7. 2000 -- A 2000 study found that hog sites are concentrated in southeast North Carolina in poor, rural and African-American communities. Populations living in close proximity are more susceptible to illness, stress, depression and physical injury. The hogs create a large amount of waste, and dust particles carry animal skin cells, feces and bacteria, which cause respiratory problems. The study reported headaches, runny nose, sore throat, coughing, diarrhea and burning eyes and decreased quality of life among residents living near CAFOs.
8. 2000 -- A 2000 study on odors from swine sites found that people living nearby reported more tension, depression, anger, fatigue, confusion, and less vigor.
9. 2000 -- The North Carolina Council of Churches noted that “Studies show that the contaminated water supplies and air emissions from hog operations adversely affect the health of those who live in the surrounding neighborhoods, causing respiratory problems, exposure to disease-causing bacteria, and psychological problems.”
10. 2001 -- In 2001, a study traced antibiotic-resistant genes from hog farms into the local ground stream.
11. 2002 – A study reported that hydrogen sulfide can cause neurological damage even at low levels.
12. 2002 – A study documented high levels of antimicrobial compounds in hog lagoons and suggested that waste sprayed onto fields spreads residues into the water stream.
13. 2002 – A paper described how CAFOs and their odor disrupt the quality of life for neighbors in rural communities.
14. 2003 -- The American Public Health Association found that “CAFO manure wastes also include organic dust, molds, bacterial endotoxins and manure-generated gases of up to 400 separate volatile compounds, such as ammonia and hydrogen sulfide, many of which are known airway irritants, allergens or respiratory hazards.”
15. 2003 – The Research Triangle Institute reported that the levels of toxins emitted by the swine sites are so high that studies have estimated hundreds of millions of dollars are being lost every year due to the health effects and premature deaths caused by the ammonia alone. Its 2003 report reviewed the health and environmental costs to North Carolina of the lagoon-and-sprayfield CAFOs. The report found that “releases from swine operations can negatively affect environmental quality through various media (air, land, groundwater, and surface water). In the process, they can impair the functioning of natural Ecosystems.” (p. 6-1). Further, “the benefits assessment can translate changes in environmental releases and impacts into measures of human well-being, expressed in monetary terms.” (p. 6-1). “Odor emissions from hog farms are a continuing concern in North Carolina, particularly for residents living in close proximity to farms.” (p. 6-3). A study “using data on housing prices in nine counties in southeastern North Carolina … found that proximity to hog farms had a significantly negative impact on housing values and that these effects varied by the size of the operation.” (p. 6-5). The report also reviewed “the reductions in incidences of health outcomes such as premature mortality, chronic bronchitis, hospitalization for asthma, and acute illnesses such as lower respiratory symptoms” if improvements were made. (p. 6-30). The report estimated “reductions in premature deaths” of “32 per year for the 50 percent reduction scenario” i.e. if ammonia pollution alone was reduced by one-half. The health cost of not reducing the ammonia was “$189 million per year.” (p. 6-33). The report noted how “there are a number of potential pathways through which humans can be exposed to pathogens originating from swine waste. Technologies that reduce releases of disease-transmitting vectors and airborne pathogens can therefore provide health benefits to exposed populations.” (p. 6-39).
16. 2004 -- A 2004 investigation found evidence of stress-mediated impacts on immune function in swine CAFO neighbors who had lower average concentration and secretion of salivary immunoglobulin A during periods of odor.
17. 2005 -- 2004-05 studies found that children had more asthma symptoms with proximity to swine CAFOs, and found that there was potential for hog-to-human transmission of drug-resistant diseases including MSRA.
18. 2005 -- A 2005 study reviewed the health effects of residents near industrial hog farms in the Duplin/Sampson County area and found respiratory, sinus, and nausea problems, and increased psychological distress.
19. 2006 -- Studies surveyed children from schools in North Carolina and correlated high rates of wheezing to proximity to hogs. The findings suggested that swine emissions and odor disproportionately affect a population of children and adults predisposed to asthma-related health outcomes and other illnesses. Children attending middle schools within 3 miles of swine CAFOs and schools where staff reported odors in buildings had more wheezing.
20. 2006 – A study examined the levels of bacteria in the air plume upwind and downwind from a CAFO. There was an increase in bacteria downwind decreasing with distance. Staphylococcus aureus was found to account for 76% of the organisms recovered. The study recommended buffering swine CAFOs from residential areas.
21. 2006 -- A 2006 study found that rural areas are more likely to rely upon well water than others and contaminated groundwater put rural populations at higher risk of nitrate poisoning linked to birth defects, hyperthyroidism, diabetes and cancer.
22. 2006 -- Researchers in North Carolina found that the closer children live to a CAFO, the greater the risk of asthma symptoms.
23. 2006 -- A National Air Emissions Monitoring Study (NAEMS) was established by agreement between the EPA and the CAFO companies including Smithfield to generate more scientific data about the air quality at CAFOs. 24 CAFOs, including two Murphy-Brown facilities, allowed monitoring. The EPA has periodically released results of the studies.
24. 2006 -- A 2006 study measured date from a CAFO that housed up to 1,000 sows for reproduction purposes. It found that bacterial concentrations with multiple antibiotic resistances or multidrug resistance were recovered inside and outside downwind of this facility at higher percentages than upwind. “This could pose a potential human health effect for those who work within or live in close proximity to these facilities.” “Those working at or inside the facility and those living in close proximity downwind of the facility could be at risk for adverse human health effects associated with exposure to large numbers of multidrug-resistant organisms.”
25. 2007 – A report found that “The encroachment of a large-scale livestock facility near homes is significantly disruptive of rural living.”
26. 2007 – A study found that contaminants find pathways into the environment from leaky lagoons, heavy rainfalls that cause overflow, and runoff from waste fields.. Individuals with weakened immune systems are at greater risk of adverse health effects close to hog farms. Infants, pregnant women, children, the elderly and those taking medications that suppress the immune system are more vulnerable to illness due to their weakened immunological state.
27. 2007 – A study found that due to factors like low income, inadequate housing, low health status, and insufficient access to medical care, racial discrepancies compound the negative impacts that hog farms create.
28. 2007 – A study noted how “Odour gives a problem when pig farms are located close to residential areas.” It “concluded that there is a large potential to reduce environmental load within pig dense areas by nutritional means.”
29. 2008 – A study found that an emerging subtype of methicillin-resistant Staphylococcus aureus (MRSA) that was found in humans came from swine confinement pigs.
30. 2008 – A study investigated residents living within 1.5 miles of industrial swine operations in neighborhoods in eastern North Carolina. The study indicated that odor from swine operations is commonly present in these communities and that the odors are related to objective environmental measurements and interruption of activities of daily life.
31. 2008 -- A 2008 report found that “Recurrent strong odors, the degradation of water bodies, and increased populations of flies are among the problems caused by CAFOs that make it intolerable for neighbors and their guests to participate in normal outdoor recreational activities or normal social activities in and around their homes.”
32. 2008 -- A 2008 study noted that for residents near CAFOs “hog odor limits several leisure time activities and social interactions which could have adverse public health consequences.” The study focused on nuisance in North Carolina, defined to include conduct that “is injurious to health, indecent, offensive to the senses, or an obstruction to the free use of property.” The study found that within 1.5 miles of CAFOs, “hog odor limits activities of daily living that participants either ‘enjoyed’ doing the most or expected to be able to perform inside and outside their homes. It restricts, for instance, activities like cookouts, barbequing, family reunions, socializing with neighbors, gardening, working outside, playing, drying laundry outside, opening doors and windows for fresh air and to conserve energy, use of well water, and growing vegetables. When we examine these restrictions in terms of types of activities and in the context of our area of study, which includes low-income rural communities with a high percentage of African Americans, the cumulative adverse impact goes beyond mere violation of property rights and has critical public health ramifications.”
33. 2008-09 -- A global swine flu pandemic was caused by H1N1 influenza virus. Research noted that one potential source of the outbreak was swine in CAFOs and that swine flu is more likely to persist in larger farms with higher pig densities. For background, in 1994, Smithfield established its Perote operations with the Mexican agrobusiness AMSA aka Agroindustrias Unidas de México S.A. de C.V. In 1999, the company bought expanded its operations in Mexico. The first reports of swine flu came from Perote, Veracruz, home to the facility operated by Smithfield. Local health officials announced a health alert and investigation. The Perote facility raised upwards of 950,000 hogs in 2008. According to news reports, the vector of the outbreak was the clouds of flies that come out of the hog barns, and the waste lagoons into which the facility spewed tons of excrement.
34. 2009 -- A 2009 study reported pig-specific MRSA strains among farmworkers. Air- and waterborne CAFO emissions can be contaminated with antibiotic-resistant microbes such as MRSA. In addition, zoonotic pathogens in hog waste, particularly bacterial agents, can travel downwind as spray aerosols and infect local populations.
35. 2009 -- A 2009 study found that individuals living in African-American communities in southeastern North Carolina near hog farms reported high rates of stress and negative mood.
36. 2010 -- A 2010 report noted how “CAFO odors can cause severe lifestyle changes for individuals in the surrounding communities and can alter many daily activities. When odors are severe, people may choose to keep their windows closed, even in high temperatures when there is no air conditioning. People also may choose to not let their children play outside and may even keep them home from school…. Odor can cause negative mood states, such as tension, depression, or anger….” The study also noted the “consistent evidence suggesting that factory farms increase asthma in neighboring communities, as indicated by children having higher rates of asthma.” Despite this and the other studies, in 2011, Wendell Murphy, Sr. indicated his belief that reports of school children contracting asthma from hog facilities were “false.”
37. 2011 -- A study summarized how “Animal manure and sewage sludge contain pathogens, endotoxins, allergens, and toxicants that have the potential to harm health and cause disease. Studies of 16 eastern North Carolina communities located near industrial hog farms that apply swine waste to the land demonstrated human exposure to airborne pollutants and dose-response relationships between pollutant levels, symptoms of illness, and stress levels in humans. Other research has demonstrated the presence of pathogens and antibiotic-resistant bacteria in surface waters near industrial swine farms.”
38. 2012 – A study sought “To determine whether neighbors around manure lagoons and massive hog confinement buildings who complained of offensive odors and symptoms had impaired brain and lung functions.” The study found that “Exposed subjects mean forced vital capacity and expiratory volume in 1 sec were reduced significantly compared to local and regional controls.” Further, “Near neighbors of hog enclosures and manure lagoon gases had impaired neurobehavioral functions and pulmonary functions and these effects extended to nearby people thought to be controls. Hydrogen sulfide must be abated because people living near lagoons cannot avoid rotten egg gas.”
39. 2013 – A study found that “Like noise and other repetitive environmental stressors, malodors may be associated with acute blood pressure increases that could contribute to development of chronic hypertension.”
40. 2013 – An article noted that “Swine finishing operations near residential areas can create public nuisance concerns due to the annoyance potential of odor emitted from the houses.” It also noted that “The diet of the animals, especially the protein content, seems to be effective in reducing odor release.”
41. 2013 – A report described how “On the coastal plain of eastern North Carolina, families in certain rural communities daily must deal with the piercing, acrid odor of hog manure—reminiscent of rotten eggs and ammonia—wafting from nearby industrial hog farms. On bad days, the odor invades homes, and people are often forced to cover their mouths and noses when stepping outside. Sometimes, residents say, a fine mist of manure sprinkles nearby homes, cars, and even laundry left on the line to dry.” It also described how hog waste “can contain pathogens, heavy metals, and antibiotic-resistant bacteria, and the spray can reach nearby homes and drinking water sources. The odor plume, which often pervades nearby communities, contains respiratory and eye irritants including hydrogen sulfide and ammonia.”
42. 2013 -- A study of the effect of hog CAFOs in Sampson County on property values found that proximity to a lagoon results in a $10,382 decline per lagoon in the value of residential parcels with homes. Proximity to hog waste lagoons results in an assessed property value loss of anywhere from $5,443-$15,563, depending on the type of residential parcel.
43. 2014 -- A 2014 study measured emissions of gases including ammonia, hydrogen sulfide, carbon dioxide, volatile organic compounds and odor from a pig nursery. “The gas and odor concentrations measured in the ventilation air from the pig rooms indicate an acute need for using gas and odor mitigation technologies. Adopting diet control and biofiltration practices simultaneously could be the best option for mitigating gas and odor emissions from pig barns.”
44. 2014 -- A 2014 study found a significant association between individuals residing in communities with pigs and live-stock associated MRSA, and found pig-associated MRSA even in people without direct contact with the swine.
45. 2014 -- An April 2014 study reviewed available data regarding ammonia (NH3) and hydrogen sulfide (H2S) emissions from swine production facilities in North America. The study included a review of information from the EPA National Air Emissions Monitoring Study (NAEMS). The study reported emissions both of NH3 and H2S and found that “The size of swine farm that may trigger the need to report NH3 emissions under the Emergency Planning and Community Right-to-Know Act (EPCRA) is 3,410 pigs on the basis of the median NH3 emission rate (4.86 kg/yr per pig), but the threshold can be as low as 992 pigs on the basis of the 90th-percentile emission rates (16.71 kg/yr per pig).” Further, the NH3 emission rates increased with increasing air temperature. The H2S emission rates were influenced by the size of the operation. The study found that median emissions rates from swine houses were 2.78 and 0.09kg per pig and year for ammonia and hydrogen sulfide, respectively. Median emissions rates from swine storage facilities were 2.08 and 0.20kg per pig and year for ammonia and hydrogen sulfide, respectively.
46. 2018 --A 2018 study by Duke University researchers found that people living in the same zip code as an industrial hog operation live shorter lives than other North Carolinians, and have higher rates of death, infant mortality, death from anemia, kidney disease, tuberculosis, and septicemia, and higher rates of emergency room visits and hospital admissions for low birthweight infants.
 Schiffman et al., “The effect of environmental odors emanating from commercial swine operations on the mood of nearby residents,” Brain Res Bull. 37(4):369-75 (1995).
 Wing et al., “Community based collaboration for environmental justice: south-east Halifax environmental reawakening,” Environ Urban 8(2):129-40 (1996); Edwards et al., “Environmental justice, swine production and farm loss in North Carolina,” Sociol Spectr 20(3):263-90 (2000); Wing et al., “Environmental injustice in North Carolina’s hog industry,” Environ Health Perspect 108:225-31 (2000); Wing et al., “Intensive livestock operations, health, and quality of live among eastern North Carolina residents,” Environmental Health Perspectives, 108:233-38 (2000); Wing et al., “The potential impact of flooding on confined animal feeding operations in eastern North Carolina,” Environ Health Perspect 110:387-91 (2002); Mirabelli et al., “Race, Poverty, and Potential Exposure of Middle-School Students to Air Emissions from Confined Swine Feeding Operations,” Environmental Health Perspectives, 114(4): 591-96 (April 2006).
 Thu, et al., “A Control Study of the Physical and Mental Health of Residents Living Near a Large-Scale Swine Operation,” Journal of Agricultural Safety and Health 3(1): 13-26 (1997) (symptoms included sputum, cough, shortness of breath, tight chest, wheezing, nausea, dizziness, weakness, fainting, headaches, plugged ears, runny nose, scratchy throat and burning eyes).
 Reynolds et al., “Air quality assessments in the vicinity of swine production facilities,” J Agromed 4:37-45 (1997).
 Schiffman et al., “Mood Changes Experienced by Persons Living Near Commercial Swine Operations,” in Pigs, Profits, and Rural Communities, Thu and Durrenberger, eds., State U. of New York Press (1998).
 Okun, “Human Health Effects Associated with the Hog Industry,” UNC-Chapel Hill (Jan. 1999), p. 2. Neighbors expressed concerns with “increased truck traffic especially at night, dead animals sitting in the hot sun awaiting pick-up and then exploding when dumped in the hauling truck, and resulting animal waste on the road from alive and dead hogs.” Id. p. 2. “The odors are generated by a mix of fresh and decomposing feces, urine, feed, the animals themselves, and dead hog carcasses.” Id. p. 4. “Neighbors of hog intensive operations and reacted to the noxious and unaesthetic air quality generated by the ammonia and hydrogen sulfide associated with the waste.” Id. p. 6.
 Wing et al., “Intensive livestock operations, health, and quality of live among eastern North Carolina residents,” Environmental Health Perspectives, 108: 233-38 (2000).
 Schiffman et al., “Potential health effects of odor from animal operations, wastewater treatment, and recycling of byproducts,” Journal of Agromedicine, 7(1): 7-81 (2000); Policy Statement Adopted by the House of Delegates, North Carolina Council of Churches (Nov. 9, 2000).
 Chee-Sanford et al., “Occurrence and Diversity of Tetracycline Resistance Genes in Lagoons and Groundwater Underlying Two Swine Production Facilities,” Applied Environmental Microbiology, 67(4): 1494-1502 (April 2001).
 Hirsch, “Hydrogen sulfide exposure without loss of consciousness: chronic effects in four cases,” Toxicology and Industrial Health 2002; 18: 51-61 (abstract: “Our data indicate that exposures to even relatively low concentrations of H2S are hazardous.”).
 Campagnolo et al., “Antimicrobial residues in animal waste and water resources proximal to large-scale swine and poultry feeding operations,” Sci Total Environ. 299(1-3):89-95 (Nov. 2002). Likewise a 2006 study identified Tetracycline-resistant genes in a hog farm, its manure lagoon, and in groundwater 250 meters downstream. Chee-Sanford, “Distribution of tetracycline- and tylosin-resistance genes in bacteria from soils exposed to swine effluent” (2006).
 Thu, “Public Health concerns for neighbors of large-scale swine production,” J Agric Saf Health 8(2):175-84 (2002).
 American Public Health Association, “Precautionary Moratorium on New Concentrated Animal Feed Operations” (Nov. 18, 2003).
 RTI International, “Benefits of Adopting Environmentally Superior Swine Waste Management Technologies in North Carolina: An Environmental and Economic Assessment,” Nov. 2003.
 RTI International, “Benefits of Adopting Environmentally Superior Swine Waste Management Technologies in North Carolina: An Environmental and Economic Assessment,” Nov. 2003.
 Avery et al., “Odor from industrial hog operations and mucosal immune function in neighbors,” Arch Environ Health 59(2):101-08 (2004).
 Chrischilles et al., “Asthma prevalence and morbidity among rural Iowa schoolchildren,” J Allergy Clin Immunol 113(1):66-71 (2004); Merchant et al., “Asthma and farm exposures in a cohort of rural Iowa children,” Environ Health Perspect 113(3):350-56 (2005); Voss et al., “Methicillin-resistant Staphylococcus aureus in Pig Farming,” Emerging Infectious Diseases, Vol. 11, No. 12 (Dec. 2005).
 Bullers, “Environmental Stressors, Perceived Control, and Health: The Case of Residents Near Large-Scale Hog Farms in Eastern North Carolina,” Human Ecology, Vol. 33, No. 1 (Feb. 2005).
 Mirabelli et al., “Race, Poverty, and Potential Exposure of Middle-School Students to Air Emissions from Confined Swine Feeding Operations,” Environmental Health Perspectives, 114(4): 591-96 (April 2006).
 Mirabelli et al., “Asthma symptoms among adolescents who attend public schools that are located near confined swine feeding operations,” Pediatrics 118(1):e66-e75 (2006).
 Green et al., “Bacterial plume emanating from the air surrounding swine confinement operations, J Occup Environ Hyg. 3(1):9-15 (2006). See also Green et al., “Endocarditis due to meticillin-resistant Staphylococcus aureus originating from pigs,” Ned Tijdschr Geneeskd 150: 2442-47 (2006); de Neeling AJ et al., “High prevalence of methicillin resistant Staphylococcus aureus in pigs,” Vet Microbiol 122: 366-72 (2007).
 Gilchrist, “The Potential Role of Concentrated Animal Feeding Operations in Infectious Disease Epidemics and Antibiotic Resistance,” Environmental Health Perspectives, 115(2): 313-16 (2006).
 Barrett, “Hogging the air: CAFO emissions reach into schools,” Environmental Health Perspectives 114(4), (2006). Likewise a 2006 study reported reviewing Iowa elementary schools found that children near the CAFO had a significantly increased prevalence of asthma. Sigurdarson et al., “School proximity to concentrated animal feeding operations and prevalence of asthma in students,” Chest 129:1486-91 (2006).
 Gibbs et al., “Isolation of antibiotic-resistant bacteria from the air plume downwind of a swine confined or concentrated animal feeding operation,” Environ Health Perspect 114: 1032-37 (2006), see p. 1036.
 Donham et al., “Community Health and Socioeconomic Issues Surrounding Concentrated Animal Feeding Operations,” Environmental Health Perspectives, 115(2): 317-20, at 318 (2007).
 Burkholder et al., “Impacts of Waste from Concentrated Animal Feeding Operations on Water Quality,” Environmental Health Perspectives, 115(2): 308-12 (2007).
 Donham, “Community Health and Socioeconomic Issues Surrounding Concentrated Animal Feeding Operations,” Environmental Health Perspectives, 115(2): 317-20 (2007).
 Aarnink, et al., “Nutrition, key factor to reduce environmental load from pig production,” Livestock Science 109, 194e203 (2007). The study described that “dietary composition and odour production and emission have a cause-and-effect relationship and that altering the sources and levels of crude protein and fermentable carbohydrates can be a promising approach to reduce odour nuisance.”
 Lewis et al., “Pigs as Source of Methicillin-Resistant Staphylococcus aureus CC398 Infections in Humans, Denmark,” Emerg Infect Dis. 14(9): 1383-89 (2008). See also van Duijkeren et al., “Transmission of methicillin-resistant Staphylococcus aureus strains between different kinds of pig farms,” Vet Microbiol 126: 383-89 (2008); Khanna et al., “Methicillin resistant Staphylococcus aureus colonization in pigs and pig farmers,” Vet Microbiol 128: 298-303 (2008).
 Wing et al., “Air pollution and odor in communities near industrial swine operations,” Environmental Health Perspectives, 116:1362-68 (2008); Schinasi et al., “Air Pollution, Lung Function, and Physical Symptoms in Communities Near Concentrated Swine Feeding Operations,” Epidemiology 22: 208-15 (2011). Likewise, a study of adults living in rural German towns with a high density of CAFOs found asthma, nasal allergies and odor annoyance. Radon et al., “Environmental exposure to confined animal feeding operations and respiratory health of neighboring residents,” Epidemiology 18:300-08 (2007).
 Pew Commission on Industrial Farm Animal Production, “Impact of Industrial Farm Animal Production on Rural Communities” (2008).
 Tajik et al., “Impact of odor from industrial hog operations on daily living activities,” New Solut 18(2):193-205 (2008), at pp. 193-98. “The types of activities that are restricted by hog odor are social interactions, physical activities, energy- and cost-saving activities, relaxing outside or indoors, and sleeping. Social activities have been shown to positively affect health, improve overall well-being, reduce stress, and strengthen social networks.” The study additionally noted that “activities like gardening, working, growing vegetables, and playing outside, naturally integrate physical activity into the day-to-day living of rural residents and have enormous health benefits. Research has already shown that residents in rural communities perceive the environmental barriers as a reason for physical inactivity. Therefore, any moderate to severe restriction in these activities could further force the rural residents into an inactive and sedentary lifestyle.”
 Schmidt, “Swine CAFOs and Novel H1N1 Flu,” Environmental Health Perspectives, Vol. 117, No. 9 (Sept. 2009); Poljak et al., “Investigation of exposure to swine influenza viruses in Ontario (Canada) finisher herds in 2004 and 2005,” Preventive Veterinary Medicine, 83:24-40 (2008). Residents of Perote believed the outbreak to be caused by contamination from pig breeding farms located in the area. They believed that the farms polluted the atmosphere and local water bodies, leading to the outbreak. According to residents, the company denied responsibility attributed the cases to "flu." However, according to a municipal health official, preliminary investigations indicated that the disease vector was a type of fly that reproduces in pig waste.
 Schmidt, “Swine CAFOs and Novel H1N1 Flu,” supra; “The Landscape of Antibiotic Resistance,” EHP 117:A244-A250 (2009). Zoonotic diseases are contagious diseases spread between animals and humans. In addition flies and other pests from CAFOs can transmit disease. Pew Commission on Industrial Farm Animal Production, “Staff Summary of Occupational and Community Public Health Impacts.” (“Nondomestic animal, birds, and insects may also contribute to the community spread of zoonotic pathogens from CAFOs.”).
 Horton et al., “Malodor as a trigger of stress and negative mood in neighbors of industrial hog operations,” American Journal of Public Health, 3(S3), S610-S615 (2009).
 Hribar, “Understanding Concentrated Animal Feeding Operations and Their Impact on Communities,” National Association of Local Boards of Health (2010), p. 6. “Houseflies, stable flies, and mosquitoes are the most common insects associated with CAFOs….. Residences closest to the feeding operations experience a much higher fly population than average homes.” Id. at p. 8.
 UNC-TV broadcast with interview of Wendell Murphy dated Nov. 20, 2011.
 Keil et al., “Suitability of public records for evaluating health effects of treated sewage sludge in North Carolina,” NC Med J 72(2):98-104 (2011).
 Kilburn, “Human Impairment from Living near Confined Animal (Hog) Feeding Operations,” Journal of Environmental and Public Health (2012).
 Wing et al., “Air Pollution from Industrial Swine Operations and Blood Pressure of Neighboring Residents,” Environ Health Perspect. 121(1):92-6 (2013).
 Schauberger, et al., “Empirical model of odor emission from deep-pit swine finishing barns to derive a standardized odor emission factor,” Atmospheric Environment 66:84-90 (2013).
 Nicole, “CAFOs and Environmental Justice: The Case of North Carolina,” Environ Health Perspect 121:A182-A189, at A185 (2013).
 Identifying Opportunities and Impacts for New Uses of Hog Waste in Eastern North Carolina, Economic Development Workshop, Department of City and Regional Planning, The University of North Carolina at Chapel Hill, Fall 2013).
 Kafle et al., “Emissions of Odor, Ammonia, Hydrogen Sulfide, and Volatile Organic Compounds from Shallow-Pit Pig Nursery Rooms,” J. of Biosystems Eng. 39(2):76-86 (2014).
 Van Rijen et al., “Livestock-Associated MRSA Carriage in Patients without Direct Contact with Livestock,” PLoS ONE 9(6): e100294 (2014).
 Liu et al., “Ammonia and hydrogen sulfide emissions from swine production facilities in North America: a meta-analysis,” J Anim Sci. 2014 Apr;92(4):1656-65.