The association between proximity to animal feeding operations and community health: a systematic review

Precarious Essential Work, Immigrant Dairy Farmworkers, and Occupational Health Experiences in Vermont

Migrant dairy workers in Vermont face a wide range of occupational and health hazards at work. This research examines the environmental risks, occupational health hazards, and health outcomes experienced by migrant dairy farm workers in Vermont. This research draws on a triangulation of sources including analysis of data—surveys and interviews with migrant dairy farmworkers gathered by the organization Migrant Justice since 2015 as well as relevant key informant interviews with community organizations across the state to characterize the occupational health experiences of migrant dairy workers in Vermont. Our results show that Vermont migrant dairy farmworkers received poor health and safety training and lacked sufficient protective gear. Over three quarters of the respondents reported experiencing harm from chemical and biological risks. Close to half the survey respondents reported headaches, itchy eyes and cough; a quarter reported breathing difficulties; three fourths reported being hurt by animal-related risks. These exposures and existing health concerns are avoidable. Migrant workers require better social representation and advocates to negotiate better work-related protection and training, access to health services, and social welfare to ensure their health and safety.

Dysregulation of murine immune functions on inhalational exposure to ammonia, dimethyl disulfide, 3-methylindole, or propionic acid

Animal husbandry workers are exposed to various malodorous compounds in the workplace. Although these compounds cause severe nuisance, no systemic investigation of their effects on the immune system has been conducted. To address this issue, we evaluated the effects of inhalational exposure to ammonia, dimethyl disulfide, 3-methylindole (3-MI), and propionic acid (PA), representing four major groups of malodorous compounds, on humoral and cellular immunity in mice. Mice were exposed to the substances (low dose: 10 µL and high dose: 200 µL) for 10 min/day for 4 weeks in a modified standard mouse cage. Neutrophil% and splenic cytotoxic T cell% were significantly lower in the high-dose ammonia group than in the vehicle control. Exposure to ammonia and 3-MI increased immature thymic T lymphocyte% relative to control and concomitantly decreased both mature helper and cytotoxic T-cell populations in the thymus. In the ammonia exposure group, levels of serum immunoglobulin E and immunoglobulin A were elevated, and the IgG2a:IgG1 ratio in the serum was reduced in a dose-dependent manner. Splenic natural killer cell activity was significantly less in the PA exposure group than in the control. Overall, our findings suggest that inhalational exposure to these malodorous substances disturbs immune homeostasis in vivo.

Concentration and composition of bioaerosol emissions from intensive farms: Pig and poultry livestock

Intensive farming is widespread throughout the UK and yet the health effects of bioaerosols which may be generated by these sites are currently not well researched. A scoping study was established to measure bioaerosols emitted from intensive pig (n = 3) and poultry farms (n = 3) during the period 2014-2015. The concentration of culturable mesophilic bacteria, Gram-negative bacteria, Staphylococcus spp., and fungi selecting for presumptive Aspergillus fumigatus were measured using single-stage impaction Andersen samplers, whilst endotoxin and (1 → 3)-β-D-glucan was undertaken using inhalable personal samplers. Particulate matter concentration was determined using an optical particulate monitor. Results showed that culturable bacteria, fungi, presumptive Staphylococcus aureus (confirmed only as Staphylococcus spp.) and endotoxin concentrations were elevated above background concentrations for distances of up to 250 m downwind of the source. Of all the culturable bioaerosols measured, bacteria and Staphylococcus spp. were identified as the most significant, exceeding published or proposed bioaerosol guidelines in the UK. In particular, culturable Staphylococcus spp. downwind was at least 61 times higher than background at the boundary and at least 8 times higher 70m downwind on the four farms tested. This research represents a novel dataset of intensive farm emissions within the UK. Future research should exploit the use of innovative culture-independent methods such as next generation sequencing to develop deeper insights into the make-up of microbial communities emitted from intensive farming facilities and which would better inform species of interest from a public health perspective.

Reflections on Odor Management for Animal Feeding Operations

Most animal feeding operation owners recognize that they need to manage odors from their operations as part of their social relationship with their neighbors and local community. That was not always the case. Odors, whether pleasant or unpleasant, can evoke strong emotions and physiological responses. Odors from animal feeding operations are normally considered unpleasant and offensive if strong smelling and smelled often or for long periods of time. Animal feeding operation owners need to be aware of their odor emissions and the impacts the odors have on their neighbors and community. Good neighbor relations and effective communications can help identify odor problems and communicate what is being done to manage them. Odor management research and education includes odor basics, key processes including generation, emissions and dispersion, impacts, community and neighbor relations, and numerous mitigation practices. Animal feeding operation owners considering practices to reduce odor emissions or their impacts need to weigh the costs, expected effectiveness, and how the practice fits into the overall operation. Policymakers need science-based information to make informed decisions that balance the concerns and needs of neighbors and the community and the businesswomen and men that own and operate the animal feeding operations. This paper provides a broad overview of animal feeding operation odors and odor management.

Intensive Livestock Farming and Residential Health: Experts' Views

The presence of intensive livestock farms in close vicinity to residential areas in the Netherlands is a complex problem characterised by knowledge uncertainty about the effects on residential health, overlapping value-driven concerns and stakeholder diversity. In order to address concerns about the health effects and effectively manage the debate about intensive livestock farming, constructive stakeholder dialogues are encouraged, informed by current scientific insights. We explored the current knowledge, beliefs and concerns of scientific experts, following the mental models approach. A summary expert model was derived from scanning the relevant literature and informed by interviews with 20 scientific experts. The study shows imprecise use of terminology by experts. Moreover, they appear to perceive intensive livestock farming not as a major health problem at least at this moment for neighbouring residents in the Netherlands. Broader themes such as (environmental) unsustainability and biodiversity loss seem a more prominent concern among the experts. Our study questions whether dialogues should only focus on residential health or cover broader values and concerns. However, mental models about risk may differ with other stakeholders, impeding communication. Hence, we will identify other stakeholders' knowledge, beliefs and value-based concerns in the light of facilitating constructed dialogues between stakeholders.

On the interpretation of bioaerosol exposure measurements and impacts on health

Bioaerosols are recognized as one of the main transmission routes for infectious diseases and are responsible for other various types of health effects through inhalation and potential ingestion. Associating exposure with bioaerosol and health problems is challenging, and adequate exposure monitoring is a top priority for aerosol scientists. The multiple factors affecting bioaerosol content, the variability in the focus of each bioaerosol exposure study, and the variations in experimental design and the standardization of methods make bioaerosol exposure studies very difficult. Therefore, the health impacts of bioaerosol exposure are still poorly understood. This paper presents a brief description of a state-of-the-art development in bioaerosol exposure studies supported by studies on several related subjects. The main objective of this paper is to propose new considerations for bioaerosol exposure guidelines and the development of tools and study designs to better interpret bioaerosol data. The principal observations and findings are the discrepancy of the applicable methods in bioaerosol studies that makes result comparison impossible. Furthermore, the silo mentality helps in creating a bigger gap in the knowledge accumulated about bioaerosol exposure. Innovative and original ideas are presented for aerosol scientists and health scientists to consider and discuss. Although many examples cited herein are from occupational exposure, the discussion has relevance to any human environment. This work gives concrete suggestions for how to design a full bioaerosol study that includes all of the key elements necessary to help understand the real impacts of bioaerosol exposure in the short term. The creation of the proposed bioaerosol public database could give crucial information to control the public health. Implications: How can we move toward a bioaerosol exposure guidelines? The creation of the bioaerosol public database will help accumulate information for long-term association studies and help determine specific exposure biomarkers to bioaerosols. The implementation of such work will lead to a deeper understanding and more efficient utilization of bioaerosol studies to prevent public health hazards.

Bioaerosols Play a Major Role in the Nasopharyngeal Microbiota Content in Agricultural Environment

Background: Bioaerosols are a major concern for public health and sampling for exposure assessment purposes is challenging. The nasopharyngeal region could be a potent carrier of long-term bioaerosol exposure agents. This study aimed to evaluate the correlation between nasopharyngeal bacterial flora of swine workers and the swine barns bioaerosol biodiversity. Methods: Air samples from eight swine barns as well as nasopharyngeal swabs from pig workers (n = 25) and from a non-exposed control group (n = 29) were sequenced using 16S rRNA gene high-throughput sequencing. Wastewater treatment plants were used as the industrial, low-dust, non-agricultural environment control to validate the microbial link between the bioaerosol content (air) and the nasopharynxes of workers. Results: A multivariate analysis showed air samples and nasopharyngeal flora of pig workers cluster together, compared to the non-exposed control group. The significance was confirmed with the PERMANOVA statistical test (p-value of 0.0001). Unlike the farm environment, nasopharynx samples from wastewater workers did not cluster with air samples from wastewater treatment plants. The difference in the microbial community of nasopharynx of swine workers and a control group suggest that swine workers are carriers of germs found in bioaerosols. Conclusion: Nasopharynx sampling and microbiota could be used as a proxy of air sampling for exposure assessment studies or for the determination of exposure markers in highly contaminated agricultural environments.

Scoping studies to establish the capability and utility of a real-time bioaerosol sensor to characterise emissions from environmental sources

A novel dual excitation wavelength based bioaerosol sensor with multiple fluorescence bands called Spectral Intensity Bioaerosol Sensor (SIBS) has been assessed across five contrasting outdoor environments. The mean concentrations of total and fluorescent particles across the sites were highly variable being the highest at the agricultural farm (2.6 cm^-3 and 0.48 cm^-3, respectively) and the composting site (2.32 cm^-3 and 0.46 cm^-3, respectively) and the lowest at the dairy farm (1.03 cm^-3 and 0.24 cm^-3, respectively) and the sewage treatment works (1.03 cm^-3 and 0.25 cm^-3, respectively). In contrast, the number-weighted fluorescent fraction was lowest at the agricultural site (0.18) in comparison to the other sites indicating high variability in nature and magnitude of emissions from environmental sources. The fluorescence emissions data demonstrated that the spectra at different sites were multimodal with intensity differences largely at wavelengths located in secondary emission peaks for λex 280 and λex 370. This finding suggests differences in the molecular composition of emissions at these sites which can help to identify distinct fluorescence signature of different environmental sources. Overall this study demonstrated that SIBS provides additional spectral information compared to existing instruments and capability to resolve spectrally integrated signals from relevant biological fluorophores could improve selectivity and thus enhance discrimination and classification strategies for real-time characterisation of bioaerosols from environmental sources. However, detailed lab-based measurements in conjunction with real-world studies and improved numerical methods are required to optimise and validate these highly resolved spectral signatures with respect to the diverse atmospherically relevant biological fluorophores.

A systematic review of the public health risks of bioaerosols from intensive farming

BACKGROUND

Population growth, increasing food demands, and economic efficiency have been major driving forces behind farming intensification over recent decades. However, biological emissions (bioaerosols) from intensified livestock farming may have the potential to impact human health. Bioaerosols from intensive livestock farming have been reported to cause symptoms and/or illnesses in occupational-settings and there is concern about the potential health effects on people who live near the intensive farms. As well as adverse health effects, some potential beneficial effects have been attributed to farm exposures in early life. The aim of the study was to undertake a systematic review to evaluate potential for adverse health outcomes in populations living near intensive livestock farms.

MATERIAL AND METHODS

Two electronic databases (PubMed and Scopus) and bibliographies were searched for studies reporting associations between health outcomes and bioaerosol emissions related to intensive farming published between January 1960 and April 2017, including both occupational and community studies. Two authors independently assessed studies for inclusion and extracted data. Risk of bias was assessed using a customized score.

RESULTS

38 health studies met the inclusion criteria (21 occupational and 1 community study measured bioaerosol concentrations, 16 community studies using a proxy measure for exposure). The majority of occupational studies found a negative impact on respiratory health outcomes and increases in inflammatory biomarkers among farm workers exposed to bioaerosols. Studies investigating the health of communities living near intensive farms had mixed findings. All four studies of asthma in children found increased reported asthma prevalence among children living or attending schools near an intensive farm. Papers principally investigated respiratory and immune system outcomes.

CONCLUSIONS

The review indicated a potential impact of intensive farming on childhood respiratory health, based on a small number of studies using self-reported outcomes, but supported by findings from occupational studies. Further research is needed to measure and monitor exposure in community settings and relate this to objectively measured health outcomes.

Survey of the effect of odour impact on communities

In the context of environmental malodour, surveys are valuable as they allow for the relatively detailed analysis of multiple factors pertaining to odour perception and subsequent reaction. However, the causes for an individual to experience odour impact while a neighbour will not are still not understood. The goal of this current survey design was to consolidate varying research paths for surveys within the environmental odour research space. This survey investigated the area of effect for wastewater treatment plants by using stratified random sampling techniques that radiated from the industrial areas. Additionally, this survey provided a "non-alerted" response to environmental malodour that represents a step forward for ecological validity. We found a small number of items relating to odour annoyance and home ownership that can be used in order to predict odour impact for individual community members. However, we also did not find any relationship with odour impact and perceived control. This survey design and analysis reconciles the varied approaches towards community surveys administered in prior literature, as well as providing information to improve future community engagement policies.

Updated systematic review: associations between proximity to animal feeding operations and health of individuals in nearby communities

OBJECTIVE

The objective of this review was to update a systematic review of associations between living near an animal feeding operation (AFO) and human health.

METHODS

The MEDLINE® and MEDLINE® In-Process, Centre for Agricultural Biosciences Abstracts, and Science Citation Index databases were searched. Reference lists of included articles were hand-searched. Eligible studies reported exposure to an AFO and an individual-level human health outcome. Two reviewers performed study selection and data extraction.

RESULTS

The search returned 3702 citations. Sixteen articles consisting of 10 study populations were included in the analysis. The health outcomes were lower and upper respiratory tracts, MRSA, other infectious disease, neurological, psychological, dermatological, otologic, ocular, gastrointestinal, stress and mood, and other non-infectious health outcomes. Most studies were observational and used prevalence measures of outcome. An association between Q fever risk and proximity to goat production was reported. Other associations were unclear. Risk of bias was serious or critical for most exposure-outcome associations. Multiplicity (i.e., a large number of potentially correlated outcomes and exposures assessed on the same study subjects) was common in the evidence base.

CONCLUSIONS

Few studies reported an association between surrogate clinical outcomes and AFO proximity for respiratory tract-related outcomes. There were no consistent dose-response relationships between surrogate clinical outcome and AFO proximity. A new finding was that Q fever in goats is likely associated with an increased Q fever risk in community members. The review results for the non-respiratory health outcomes were inconclusive because only a small number of studies were available or the between-study results were inconsistent.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014010521.

Ambient Ammonia Exposures in an Agricultural Community and Pediatric Asthma Morbidity

BACKGROUND

Large-scale animal feeding operations compromise regional air quality in the rural US through emission of pollutants, such as ammonia gas. Exposure to airborne pollution from animal feeding operations may cause pediatric asthma exacerbations in surrounding communities.

OBJECTIVES

To describe spatial and temporal patterns in ambient ammonia concentrations in an agricultural region, and to investigate associations between short-term fluctuations in ammonia and subsequent changes in respiratory health in children with asthma.

METHODS

For 13 months in the Yakima Valley of Washington State, 14 monitors sampled ammonia in outdoor air for 24-hour periods every 6 days. School-age children with asthma (n = 51) were followed for two health outcomes: biweekly reports of asthma symptoms and quick relief medication usage, and daily measurements of forced expiratory volume in 1 second. We assessed associations between each outcome and ammonia using generalized estimating equations.

RESULTS

Twenty-four-hour ammonia concentrations varied from 0.2 to 238.1 μg/m during the study period and displayed a strong correlation with proximity to animal feeding operations. The percentage of forced expiratory volume in 1 second was 3.8% lower (95% confidence interval = 0.2, 7.3) per interquartile increase in 1-day lagged ammonia concentration and 3.0% lower (95% confidence interval = 0.5, 5.8) for 2-day lagged concentration. We observed no associations between self-reported asthma symptoms or medication usage and estimated ammonia exposure.

CONCLUSIONS

Ammonia concentrations were elevated in this community and strongly predicted by proximity to animal feeding operations. Ammonia's association with acute lung function decrements in children with asthma in the surrounding community may be causal or, alternatively, ammonia may be a marker for other pollutants from animal feeding operations associated with respiratory effects.

Slaughterhouses Fungal Burden Assessment: A Contribution for the Pursuit of a Better Assessment Strategy

In slaughterhouses, the biological risk is present not only from the direct or indirect contact with animal matter, but also from the exposure to bioaerosols. Fungal contamination was already reported from the floors and walls of slaughterhouses. This study intends to assess fungal contamination by cultural and molecular methods in poultry, swine/bovine and large animal slaughterhouses. Air samples were collected through an impaction method, while surface samples were collected by the swabbing method and subjected to further macro- and micro-scopic observations. In addition, we collected air samples using the impinger method in order to perform real-time quantitative PCR (qPCR) amplification of genes from specific fungal species, namely A. flavus, A. fumigatus and A. ochraceus complexes. Poultry and swine/bovine slaughterhouses presented each two sampling sites that surpass the guideline of 150 CFU/m³. Scopulariopsis candida was the most frequently isolated (59.5%) in poultry slaughterhouse air; Cladosporium sp. (45.7%) in the swine/bovine slaughterhouse; and Penicillium sp. (80.8%) in the large animal slaughterhouse. Molecular tools successfully amplified DNA from the A. fumigatus complex in six sampling sites where the presence of this fungal species was not identified by conventional methods. This study besides suggesting the indicators that are representative of harmful fungal contamination, also indicates a strategy as a protocol to ensure a proper characterization of fungal occupational exposure.

Doctor-diagnosed health problems in a region with a high density of concentrated animal feeding operations: a cross-sectional study

BACKGROUND

There is growing interest in health risks of residents living near concentrated animal feeding operations (CAFOs). Previous research mostly focused on swine CAFOs and self-reported respiratory conditions. The aim was to study the association between the presence of swine, poultry, cattle and goat CAFOs and health of Dutch neighbouring residents using electronic medical records from general practitioners (GPs).

METHODS

Data for the year 2009 were collected of 119,036 inhabitants of a rural region with a high density of CAFOs using information from GIAB (high exposed population). A comparison was made with GP data from 78,060 inhabitants of rural areas with low densities of CAFOs (low exposed population). Associations between the number of CAFOs near residents' homes and morbidity were determined by multilevel (cross-classified) logistic regression.

RESULTS

In 2009, the prevalence of most respiratory and gastrointestinal conditions was similar in the high and low exposed population. Exceptions were pneumonia, atopic eczema and unspecified infectious diseases with an increased prevalence, and sinusitis with a decreased prevalence in the high exposed population. Within the high CAFO density region, the number of poultry, cattle and swine CAFOs near residents' homes was not associated with allergic, respiratory or gastrointestinal conditions. Conversely, each additional goat CAFO within the postal code area of residents' homes significantly increased the odds of unspecified infectious disease and pneumonia by 87 and 41 percent, respectively.

CONCLUSIONS

Using GP records, pneumonia and unspecified infectious diseases were positively associated with the number of goat CAFOs near residents' homes, but no association was found between swine, cattle, and poultry CAFOs and respiratory, allergic or gastrointestinal conditions.

Industrial Food Animal Production and Community Health

Industrial food animal production (IFAP) is a source of environmental microbial and chemical hazards. A growing body of literature suggests that populations living near these operations and manure-applied crop fields are at elevated risk for several health outcomes. We reviewed the literature published since 2000 and identified four health outcomes consistently and positively associated with living near IFAP: respiratory outcomes, methicillin-resistant Staphylococcus aureus (MRSA), Q fever, and stress/mood. We found moderate evidence of an association of IFAP with quality of life and limited evidence of an association with cognitive impairment, Clostridium difficile, Enterococcus, birth outcomes, and hypertension. Distance-based exposure metrics were used by 17/33 studies reviewed. Future work should investigate exposure through drinking water and must improve exposure assessment with direct environmental sampling, modeling, and high-resolution DNA typing methods. Investigators should not limit study to high-profile pathogens like MRSA but include a broader range of pathogens, as well as other disease outcomes.

Interaction of the role of Concentrated Animal Feeding Operations (CAFOs) in Emerging Infectious Diseases (EIDS)

Most significant change in the evolution of the influenza virus is the rapid growth of the Concentrated Animal Feeding Operations (CAFOs) on a global scale. These industrial agricultural operations have the potential of housing thousands of animals in a relatively small area. Emerging Infectious Diseases (EIDs) event can be considered as a shift in the pathogen–host–environment interplay characteristics described by Engering et al. (2013). These changes in the host–environment and the disease ecology are key to creating novel transmission patterns and selection of novel pathogens with a modification of genetic traits. With the development of CAFOs throughout the world, the need for training of animal caretakers to observe, identify, treat, vaccinate and cull if necessary is important to safeguard public health. The best defense against another pandemic of Emerging Infectious Diseases (EIDs) is the constant monitoring of the livestock and handlers of CAFOs and the live animal markets. These are the most likely epicenter of the next pandemic.

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Most significant change in the evolution of airborne virus evolution is the rapid growth of the Concentrated Animal Feeding Operations.

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Changes in the host–environment and the disease ecology are creating novel transmission patterns and selection of genetic traits.

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The best defense against pandemic of Emerging Infectious Diseases (EIDs) is the constant monitoring of CAFOs.

The relation between modeled odor exposure from livestock farming and odor annoyance among neighboring residents

PURPOSE

Odor annoyance is an important environmental stressor for neighboring residents of livestock farms and may affect their quality of life and health. However, little is known about the relation between odor exposure due to livestock farming and odor annoyance. Even more, the relation between odor exposure and odor annoyance is rather complicated due to variable responses among individuals to comparable exposure levels and a large number of factors (such as age, gender, education) that may affect the relation. In this study, we (1) investigated the relation between modeled odor exposure and odor annoyance; (2) investigated whether other factors can affect this relation; and (3) compared our dose-response relation to a dose-response relation established in a previous study carried out in the Netherlands, more than 10 years ago, in order to investigate changes in odor perception and appreciation over time.

METHODS

We used data from 582 respondents who participated in a questionnaire survey among neighboring residents of livestock farms in the south of the Netherlands. Odor annoyance was established by two close-ended questions in a questionnaire; odor exposure was estimated using the Stacks dispersion model.

RESULTS

The results of our study indicate a statistically significant and positive relation between modeled odor exposure and reported odor annoyance from livestock farming (OR 1.92; 95 % CI 1.53-2.41). Furthermore, age, asthma, education and perceived air pollution in the environment are all related to odor annoyance, although they hardly affect the relation between estimated livestock odor exposure and reported odor annoyance. We also found relatively more odor annoyance reported among neighboring residents than in a previous study conducted in the Netherlands.

CONCLUSIONS

We found a strong relation between modeled odor exposure and odor annoyance. However, due to some uncertainties and small number of studies on this topic, further research and replication of results is recommended.

The association between proximity to animal-feeding operations and community health: a protocol for updating a systematic review

BACKGROUND

Livestock and poultry operations that feed large numbers of animals are common. Facility capacity varies, but it is not uncommon for facilities to house 1,000 swine with multiple barns at a single site, feedlots to house 50,000 cattle, and poultry houses to house 250,000 hens. There is primary research that suggests livestock facilities that confine animals indoors for feeding can represent a health hazard for surrounding communities. In this protocol, we describe a review about the association between proximity to animal-feeding operations (AFOs) and the health of individuals in nearby communities. A systematic review of the topic was published by some members of our group in 2010. The purpose of this review is to update that review.

METHODS/DESIGN

The populations of interest are people living in communities near livestock production facilities. Outcomes of interest are any health outcome measured in humans such as respiratory disease, gastrointestinal disease, and mental health. Measures of antibiotic resistance in people from the communities compared to measures of resistance found in animals and the environment on animal-feeding operations will also be summarized. The exposure of interest will be exposure to livestock production using a variety of metrics such as distance from facilities, endotoxin levels, and measures of odor. Electronic searches will be conducted using MEDLINE and MEDLINE In-Process (via OvidSP), CAB Abstracts (via Web of Knowledge), and Science Citation Index (via Web of Knowledge). No language or date restriction will be applied. We will access the risk of bias using a pilot version of a tool developed by the Methods Groups of the Cochrane Collaboration for non-randomized interventions.We propose to conduct a meta-analysis for each health metric (e.g., combining all respiratory disease outcomes, combining all gastrointestinal outcomes). A planned subgroup analysis will be based on the domains of the risk of bias.

DISCUSSION

This systematic review will provide synthesis of current evidence reporting the association between living near an animal-feeding operation and human health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014010521.

Distribution of Industrial Farms in the United States and Socioeconomic, Health, and Environmental Characteristics of Counties

The method of producing food animals has changed in the United States over the past century, moving from traditional burns to enclosed structures resembling industrial buildings, where animals are raised in high stocking density (commonly known as “Concentrated Animal Feeding Operations,” CAFOs). The objective to maximize profit has resulted in poor farm management; raised issues of environmental pollution, public health, animal rights, and environmental justice, and had socio-economic impacts. Studies concerning the issues are limited to specific regions and types of CAFOs. In addition, studies on the spatial distribution and temporal changes of CAFO at a country scale are lacking. This study bridges some of the gaps by analyzing the spatial distribution of industrial farms in the United States in 2002 and 2007 and their relationship with vulnerable population and exploring the relationships among the concentrations of farms, socio-economic, health, and environmental characteristics of the counties. A range of spatial statistics tools were applied in this study. The study revealed variations in spatial distribution depending on the type of the CAFOs. The issue of environmental justice was found prevalent depending on the types of industrial farms. Each type of industrial farm was found to interact uniquely with the selected demographic, health, and environmental parameters.

Children's environmental health in agricultural settings

Children residing in rural settings may encounter environmental hazards derived from agricultural production activities. Health consequences of organic dusts, farm chemicals including pesticides, machinery noise, excess sun exposure, and zoonotic infectious agents have been clearly described among farm-working adults. The author reviews the related evidence base on child health with a life-stage perspective on their differential exposure and vulnerabilities. Methemoglobinemia among infants consuming nitrate-contaminated well water, neurodevelopmental health impacts associated with early life exposure to organophosphate pesticides, and diarrheal disease due to zoonotic infectious agents are well-described pediatric concerns. There is suggestive but more limited evidence for respiratory health consequences from air contaminants associated with confined animal feeding operations and hearing deficits for children exposed to machinery-related noise. Many contaminants of concern for children in these environments remain largely understudied-diesel exhaust, biomass burning, solvents, veterinary antibiotics, and silica-containing particulate matter. Overall, the state of knowledge and programmatic activities on agriculturally derived environmental contaminants and child health is immature and much less complete than for working adults. This overview provides a context for research, policy, and programmatic needs.

Respiratory health effects of large animal farming environments

With increases in large animal-feeding operations to meet consumer demand, adverse upper and lower respiratory health effects in exposed agriculture workers are a concern. The aim of this study was to review large animal confinement feeding operational exposures associated with respiratory disease with a focus on recent advances in the knowledge of causative factors and cellular and immunological mechanisms. A PubMed search was conducted with the keywords airway, farm, swine, dairy, horse, cattle inflammation, organic dust, endotoxin, and peptidoglycan, among items were published between 1980 and now. Articles were selected based on their relevance to environmental exposure and reference to airway diseases. Airway diseases included rhinitis, sinusitis, mucus membrane inflammation syndrome, asthma, chronic bronchitis, chronic obstructive pulmonary disease, hypersensitivity pneumonitis, and organic dust toxic syndrome. There is lower prevalence of immunoglobulin (Ig) E-mediated asthma and atopy in farmers and their children, but organic dust worsens existing asthma. Multiple etiologic factors are linked to disease, including allergens, organic dusts, endotoxins, peptidoglycans, and gases. Large animal confinement feeding operations contain a wide diversity of microbes with increasing focus on gram-positive bacteria and archaebacteria as opposed to gram-negative bacteria in mediating disease. Toll-like receptors (TLR) and nucleotide oligomerization domain (NOD)-like innate immune pathways respond to these exposures. Finally, a chronic inflammatory adaptation, tolerance-like response in chronically exposed workers occurs. Large animal confinement farming exposures produce a wide spectrum of upper and lower respiratory tract diseases due to the complex diversity of organic dust, particulates, microbial cell wall components, and gases and resultant activation of various innate immune receptor signaling pathways.