Positive human health effects of wearing a respirator in a swine barn

Can individual protective measures safeguard cardiopulmonary health from air pollution? A systematic review and meta-analysis

Evidence supporting the effect of individual protective measures (IPMs) on air pollution is relatively scarce. In this study, we performed a systematic review and meta-analysis to investigate the effects of air purifiers, air-purifying respirators, and cookstove changes on cardiopulmonary health outcomes. We searched PubMed, Scopus, and Web of Science until December 31, 2022, 90 articles and 39,760 participants were included. Two authors independently searched and selected the studies, extracted information, and assessed each study's quality and risk of bias. We performed meta-analyses when three or more studies were available for each IPMs, with comparable intervention and health outcome. Systematic review showed that IPMs were beneficial in children and elderly with asthma along with healthy individuals. Meta-analysis results showed a reduction in cardiopulmonary inflammation using air purifiers than in control groups (with sham/no filter) with a decrease in interleukin 6 by -0.247 μg/mL (95% confidence intervals [CI] = -0.413, -0.082). A sub-group analysis for air purifier as an IPMs in developing counties reduced fractional exhaled nitric oxide by -0.208 ppb (95% confidence intervals [CI] = -0.394, -0.022). However, evidence describing the effects of air purifying respirator and cook stove changes on cardiopulmonary outcomes remained insufficient. Therefore, air purifiers can serve as efficient IPMs against air pollution. The beneficial effect of air purifiers is likely to have a greater effect in developing countries than in developed countries.

Particulate Matter in Swine Barns: A Comprehensive Review

Particulate matter (PM) represents an air quality management challenge for confined swine production systems. Due to the limited space and ventilation rate, PM can reach relatively high concentrations in swine barns. PM in swine barns possesses different physical, chemical, and biological characteristics than that in the atmosphere and other indoor environments. As a result, it exerts different environmental and health effects and creates some unique challenges regarding PM measurement and mitigation. Numerous research efforts have been made, generating massive data and information. However, relevant review reports are sporadic. This study aims to provide an updated comprehensive review of swine barn PM, focusing on publications since 1990. It covers various topics including PM characteristics, sources, measurement methods, and in-barn mitigation technologies. As PM in swine barns is primarily of biological origins, bioaerosols are reviewed in great detail. Relevant topics include bacterial/fungal counts, viruses, microbial community composition, antibiotic-resistant bacteria, antibiotic resistance genes, endotoxins, and (1→3)-β-D-glucans. For each topic, existing knowledge is summarized and discussed and knowledge gaps are identified. Overall, PM in swine barns is complicated in chemical and biological composition and highly variable in mass concentrations, size, and microbial abundance. Feed, feces, and skins constitute the major PM sources. Regarding in-barn PM mitigation, four technologies (oil/water sprinkling, ionization, alternation of feed and feeders, and recirculating air filtration) are dominant. However, none of them have been widely used in commercial barns. A collective discussion of major knowledge gaps and future research needs is offered at the end of the report.

Personal protective equipment use during industrial hog operation work activities and acute lung function changes in a prospective worker cohort, North Carolina 2014-2015

INTRODUCTION

Occupational activities related to industrial hog operation (IHO) worker lung function are not well defined. Therefore, we aimed to identify IHO work activities associated with diminished respiratory function and the effectiveness, if any, of personal protective equipment (PPE) use on IHOs.

METHODS

From 2014 to 2015, 103 IHO workers were enrolled and followed for 16 weeks. At each biweekly visit, work activities and PPE use were self-reported via questionnaire and lung function measurements were collected via spirometry. Generalized linear and linear fixed-effects models were fitted to cross-sectional and longitudinal data.

RESULTS

Increasing years worked on an IHO were associated with diminished lung function, but baseline and longitudinal work activities were largely inconsistent in direction and magnitude. Unexpectedly, a -0.3 L (95% confidence interval: -0.6, -0.04) difference in forced expiratory volume in the first second (FEV₁ ) was estimated when workers wore PPE consistently (≥80% of the time at work) versus those weeks they did not. In post-hoc analyses, we found that coveralls and facemasks were worn less consistently when workers experienced worse barn conditions and had more contact with pigs, but coveralls were worn more consistently as cleaning activities increased.

CONCLUSIONS

Similar to past studies, baseline estimates were likely obscured by healthy worker effect bias, but showed decrements in worker lung function as years of work increased. A challenge to disentangling the effect of work activities on lung function was the discovery that IHO workers used PPE differently according to the work task. These data suggest that interventions may be targeted toward improving barn conditions so that workers can consistently utilize IHO-provided PPE.

Self-reported work activities, eye, nose, and throat symptoms, and respiratory health outcomes among an industrial hog operation worker cohort, North Carolina, USA

INTRODUCTION

Respiratory disease among industrial hog operation (IHO) workers is well documented; however, it remains unclear whether specific work activities are more harmful and if personal protective equipment (PPE), as used by workers, can reduce adverse health outcomes.

METHODS

IHO workers (n = 103) completed baseline and up to eight bi-weekly study visits. Workers reported typical (baseline) and transient (bi-weekly) work activities, PPE use, and physical health symptoms. Baseline and longitudinal associations were assessed using generalized logistic and fixed-effects logistic regression models, respectively.

RESULTS

At baseline, reports of ever versus never drawing pig blood, applying pesticides, and increasing years worked at any IHO were positively associated with reports of eye, nose, and/or throat irritation. Over time, transient exposures, associated with dustiness in barns, cleaning of barns, and pig contact were associated with increased odds of sneezing, headache, and eye or nose irritation, particularly in the highest categories of exposure. When PPE was used, workers had lower odds of symptoms interfering with sleep (odds ratio [OR]: 0.1; 95% confidence interval [CI]: 0.01-0.8), and eye or nose irritation (OR: 0.1; 95% CI: 0.02-0.9). Similarly, when they washed their hands eight times or more per shift (median frequency) versus less frequently, the odds of any respiratory symptom were reduced (OR: 0.3; 95% CI: 0.1-0.8).

CONCLUSIONS

In this healthy volunteer worker population, increasingly unfavorable IHO activities were associated with self-reported eye, nose, throat, and respiratory health symptoms. Strong protective associations were seen between PPE use and handwashing and the odds of symptoms, warranting further investigation.

The use of personal protective equipment during common industrial hog operation work activities and acute lung function changes in a prospective worker cohort, North Carolina, USA

Introduction

As occupational activities related to acute industrial hog operation (IHO) worker lung function are not well defined, we aimed to identify IHO work activities associated with diminished respiratory function and the effectiveness, if any, of personal protective equipment (PPE) on IHOs.

Methods

From 2014-2015, 103 IHO workers were enrolled and followed for 16 weeks. At each bi-weekly visit, lung function measurements were collected via spirometry and work activities and PPE use were self-reported via questionnaire. Generalized linear and linear fixed-effects models were fitted to cross-sectional and longitudinal data.

Results

At baseline, increasing years worked on an IHO were associated with diminished lung function, but other activities were less consistent in direction and magnitude. In longitudinal models, only reports of working in feeding/finisher barns, showed a consistent association. However, a -0.3 L (95% confidence interval: -0.6, -0.04) difference in FEV ₁ was estimated when workers wore PPE consistently versus those weeks they did not. In post-hoc analyses, we found that coveralls and facemasks were worn less consistently when workers experienced worse barn conditions and had more contact with pigs, but coveralls were worn more consistently as cleaning activities increased.

Conclusions

Similar to past studies, baseline estimates were likely obscured by healthy worker bias. Also making it challenging to disentangle the effect of work activities on lung function was the discovery that IHO workers used PPE differently according to work task. These data suggest that interventions may be targeted toward improving barn conditions so that workers can consistently utilize IHO-provided PPE.

KEY MESSAGES

What is already known about this subject?: Working on industrial hog operations may be deleterious to long- and short-term respiratory health due to airborne bacteria, endotoxin, hazardous gases, dust, and dander in barns. In efficacy studies PPE has been shown to be protective, but studies have shown that PPE utilization among hog workers has historically been sub-optimal.What are the new findings?: As barn conditions worsened and contact with pigs increased, workers in this cohort reported wearing coveralls and face masks less often; however, they reported increased PPE use as they conducted more cleaning activities at work. During weeks when workers wore PPE their lung function declined, a possible cause being the improper use of the equipment leading to a false sense of protection or re-exposure to hazardous contaminants.How might this impact on policy or clinical practice in the foreseeable future?: Given COVID-19, the H1N1 "swine flu" pandemic, our knowledge of antimicrobial resistant pathogens, and increasing awareness about how food systems are linked to the spread of emerging infectious diseases, occupational health intervention research and workplace policies may focus on creating barn environments that are more conducive to PPE use which could help protect workers and consequently the community.

HMGB1-RAGE Signaling Plays a Role in Organic Dust-Induced Microglial Activation and Neuroinflammation

Occupational exposure to contaminants in agriculture and other industries is known to cause significant respiratory ailments. The effect of organic dust on lung inflammation and tissue remodeling has been actively investigated over many years but the adverse effect of organic dust-exposure on the central vital organ brain is beginning to emerge. Brain microglial cells are a major driver of neuroinflammation upon exposure to danger signals. Therefore, we tested a hypothesis that organic dust-exposure of microglial cells induces microglial cell activation and inflammation through HMGB1-RAGE signaling. Mouse microglial cells were exposed to organic dust extract showed a time-dependent increase in cytoplasmic translocation of high-mobility group box 1 (HMGB1) from the nucleus, increased expression of receptor for advanced glycation end products (RAGE) and activation of Iba1 as compared to control cells. Organic dust also induced reactive oxygen species generation, NF-κB activation, and proinflammatory cytokine release. To establish a functional relevance of HMGB1-RAGE activation in microglia-mediated neuroinflammation, we used both pharmacological and genetic approaches involving HMGB1 translocation inhibitor ethyl pyruvate (EP), anti-HMGB1 siRNA, and NOX-inhibitor mitoapocynin. Interestingly, EP effectively reduced HMGB1 nucleocytoplasmic translocation and RAGE expression along with reactive oxygen species (ROS) generation and TNF-α and IL-6 production but not NF-κB activation. HMGB1 knockdown by siRNA also reduced both ROS and reactive nitrogen species (RNS) and IL-6 levels but not TNF-α. NOX2 inhibitor mitoapocynin significantly reduced RNS levels. Collectively, our results demonstrate that organic dust activates HMGB1-RAGE signaling axis to induce a neuroinflammatory response in microglia and that attenuation of HMGB1-RAGE activation by EP and mitoapocynin treatments or genetic knockdown can dampen the neuroinflammation.

The Effect of a Knowledge-Based Intervention on the Use of Respirators in the Norwegian Smelter Industry

Introduction

The present study investigated the effect of interventions aiming to improve attitudes toward the use of respiratory protective equipment (RPE), knowledge of RPE and the use of RPE in the Norwegian smelter industry.

Method

The surveys received 567 respondents to baseline and 240 respondents 2 weeks after the intervention. Participants were invited to either a fit-testing of respirators [Group 1] or a fit-testing combined with a lecture on exposure [Group 2], health effects and RPE. The control group [Group 3] received no training. Questionnaires containing measures of subjective knowledge, attitudes and behavior regarding RPE use were assessed.

Results

Testing indicated an improvement in knowledge of RPE and a reduction in perceived inconveniences regarding the use of RPE for both intervention groups. Group 1 showed an improvement in attitudes and organizational support, while intervention Group 2 showed an improvement in subjective norms related to RPE use. Intention to use or rate of respirator use was not shown to change significantly for any group using paired testing. Regression analysis indicated that participation in either intervention influenced intention to use respirators. The effect was significant for Group 1 and was marginally significant for intervention Group 2.

Conclusion

The results indicate that interventions can increase workers’ knowledge and attitudes, and reduce perceived inconvenience regarding the use of respiratory protective equipment. However, even though some variables seemed to positively change, reported respirator use did not improve for either groups participating in the study. It may be that physical barriers with regards to using RPE, such as fogging of protective goggles, sweating, breathing and communication issues outweigh individual attitudes, intentions and social pressure to use respirators.

Practical Applications

The tailored course and practical training in RPE use in the current intervention can be applied in the smelting industry to provide up to date information on dust exposure, health effects and protective equipment. Some adjustments may be warranted for the content to fit specific risks and exposures of other industries. However, the general pedagogical framework of the educational material regarding health effects and RPE should be useful for most heavy industries.

Cohort profile: the Saskatchewan Rural Health Study-adult component

OBJECTIVES

Less is known about the respiratory health of general farming and non-framing populations. A longitudinal Saskatchewan Rural Health Study (SRHS) was conducted to explore the association between individual and contextual factors with respiratory health outcomes in these populations. Hence, the objectives are to: (i) describe the updated methodology of longitudinal SRHS-an extension of baseline survey methodology published earlier; (ii) compare baseline characteristics and the prevalences of respiratory health outcomes between drops-outs and completers; and (iii) summarize key findings based on baseline survey data.

RESULTS

The SRHS was a prospective cohort study conducted in two phases: baseline survey in 2010 and a follow-up in 2014. Each survey consisted of two components, self-administered questionnaire and clinical assessments. At baseline, 8261 participants (≥ 18 years) (4624 households) and at follow-up, 4867 participants (2797 households) completed the questionnaires. Clinical assessments on lung functions and/or allergies were conducted among a sub-group of participants from both the surveys. To date, we published 15 peer-reviewed manuscripts and 40 abstracts in conference proceedings. Findings from the study will improve the knowledge of respiratory disease etiology and assist in the development and targeting of prevention programs for rural populations in Saskatchewan, Canada.

Reliability of N95 respirators for respiratory protection before, during, and after nursing procedures

BACKGROUND

The adequate fit of an N95 respirator is important for health care workers to reduce the transmission of airborne infectious diseases in the clinical setting. This study aimed to evaluate whether adequately sealed N95 respirators may provide consistent protection for the wearer while performing nursing procedures.

METHODS

Participants were a group of nursing students (N = 120). The best fitting respirator for these participants was identified from the 3 common models, 1860, 1860S, and 1870+ (3M), using the quantitative fit test (QNFT) method. Participants performed nursing procedures for 10-minute periods while wearing a backpack containing the portable aerosol spectrometers throughout the assessment to detect air particles inside the respirator.

RESULTS

The average fit factor of the best fitting respirator worn by the participants dropped significantly after nursing procedures (184.85 vs 134.71) as detected by the QNFT. In addition, significant differences in particle concentration of different sizes (>0.3, >0.4, >1.0, and >4.0 µm) inside the respirator were detected by the portable aerosol spectrometers before, during, and after nursing procedures.

CONCLUSIONS

Body movements during nursing procedures may increase the risk of face seal leakage. Further research, including the development of prototype devices for better respirator fit, is necessary to improve respiratory protection of users.

Utah Regional Differences in Respirator Use and Fit Testing among Pesticide Applicators

The purpose of this study was to determine regional differences within Utah in response to piloting a mobile respirator training and fit assessment program for pesticide applicators. The objectives were to describe worker perceptions of respirator use and training experiences. Pilot trainings were offered in two southern counties and two northern counties of Utah. A total of 141 individuals completed the post-training questionnaire regarding use and fit testing experience with respirators as well as perceptions of the benefits to protecting respiratory health. The majority of respondents were male (95.7%, f = 112). The proportion of participants in the southern counties who had respirator training experience (61.0%, f = 25) was not significantly higher (2 = 3.763, df = 1, p = 0.05) than the proportion of participants in the northern counties (43.0%, f = 43). Three-fourths (73.5%, f = 72) of participants in the northern counties agreed that they expect to wear a respirator in dusty conditions, while two-thirds (61.0%, f = 25) of participants in the southern counties agreed that they expect to wear a respirator in dusty conditions. The results indicated that more training should be done to improve perceptions and beliefs about using respirators. A high priority for this population will be identification of comfortable respirator options as well as communicating the importance of proper fit testing.

Eggshells as a source for occupational exposure to airborne bacteria in hatcheries

Occupational exposure to high concentrations of airborne bacteria in poultry production is related to an increased risk of respiratory disorders. However, potential sources and formation of hatchery bioaerosols are rarely characterized. In this study, bacterial multiplication on fresh shell fragments from turkey hatching eggs under conditions present in a hatcher incubator was investigated. A 10⁵-fold amplification was observed both by colony count and total cell count gaining 4 × 10⁷ cfu/cells per gram eggshell within 30 hr of incubation. Furthermore, the bacterial community present on eggshells was analyzed by generation of 16S rRNA gene clone libraries and identification of eight isolates. RFLP analysis revealed no shift in community composition during incubation and Enterococcus faecalis and Enterococcus gallinarum were found as the predominant species on turkey eggshells, both have been classified as risk group 2 microorganisms (German TRBA 466). Since Enterococcus spp. were found as predominant species on turkey eggshells, contribution of this genus to bioaerosol formation was demonstrated. During different work activities with poult and eggshell handling concentrations of airborne enterococci up to 1.3 × 10⁴ cfu m^-3 were detected. In contrast, no enterococci were identified at a day without poult or eggshell processing. In conclusion, turkey hatching eggs carry a viable specific microflora from breeder flocks to hatcheries. After hatching of turkey poults, hatcher incubators and eggshell fragments provide appropriate conditions for excessive bacterial growth. Thus, high bacterial loads on eggshell fragments are a source of potential harmful bioaersols caused by air flows, poult activity, and handling of equipment.

A comprehensive review of levels and determinants of personal exposure to dust and endotoxin in livestock farming

The respiratory health effects of livestock farming have been on debate for more than three decades. Endotoxin-contaminated organic dusts are considered as the most important respiratory hazards within livestock environments. A comprehensive review of the knowledge from studies assessing the exposure status of livestock farmers is still to be published. The present study reviews research published within the last 30 years on personal exposure of livestock farmers to organic dust and endotoxin, focusing on studies on pig, poultry and cattle farmers. Applied measurement methods and reported levels of personal exposure for the total, inhalable and respirable fractions are summarized and discussed, with emphasis on the intensity of exposure and the size and distribution of the reported exposure variability. In addition, available evidence on potential determinants of personal exposure to dust and endotoxin among these farmers are documented and discussed, taking results from exposure determinant studies using stationary sampling approaches into consideration. Research needs are addressed from an epidemiological and industrial hygiene perspective. Published studies have been heterogeneous in design, and applied methodologies and results were frequently inadequately reported. Despite these limitations and the presence of an enormous variability in personal exposure to dust and endotoxin, no clear downward trends in exposure with time were observed, suggesting that working environments within stables remains largely uncontrolled. Exposure control and prevention strategies for livestock farmers are urgently required. These should focus on the development of novel and improved methods of controlling dust and endotoxin exposure within stables based on the currently available knowledge on determinants of exposure.

A novel approach to fit testing the N95 respirator in real time in a clinical setting

The instant measurements provided by the Portacount fit-test instrument have been used as the gold standard in predicting the protection of an N95 respirator in a laboratory environment. The conventional Portacount fit-test method, however, cannot deliver real-time measurements of face-seal leakage when the N95 respirator is in use in clinical settings. This research was divided into two stages. Stage 1 involved developing and validating a new quantitative fit-test method called the Personal Respiratory Sampling Test (PRST). In Stage 2, PRST was evaluated in use during nursing activities in clinical settings. Eighty-four participants were divided randomly into four groups and were tested while performing bedside nursing procedures. In Stage 1, a new PRST method was successfully devised and validated. Results of Stage 2 showed that the new PRST method could detect different concentrations and different particle sizes inside the respirator while the wearer performed different nursing activities. This new fit-test method, PRST, can detect face seal leakage of an N95 respirator being worn while the wearer performs clinical activities. Thus, PRST can help ensure that the N95 respirator actually fulfils its function of protecting health-care workers from airborne pathogens.

Modeled effectiveness of ventilation with contaminant control devices on indoor air quality in a swine farrowing facility

Because adverse health effects experienced by swine farm workers in concentrated animal feeding operations (CAFOs) have been associated with exposure to dust and gases, efforts to reduce exposures are warranted, particularly in winter seasons when exposures increase due to decreased ventilation. Simulation of air quality and operating costs for ventilating swine CAFO, including treating and recirculating air through a farrowing room, was performed using mass and energy balance equations over a 90-day winter season. System operation required controlling heater operation to achieve room temperatures optimal to ensure animal health (20 to 22.5 °C). Five air pollution control devices, four room ventilation rates, and five recirculation patterns were examined. Inhalable dust concentrations were easily reduced using standard industrial air pollution control devices, including a cyclone, filtration, and electrostatic precipitator. Operating ventilation systems at 0.94 m3 s(-1) (2000 cfm) with 75 to 100% recirculation of treated air from cyclone, electrostatic precipitator, and shaker dust filtration system achieves adequate particle control with operating costs under $1.00 per pig produced ($0.22 to 0.54), although carbon dioxide (CO2) concentrations approach 2000 ppm using in-room ventilated gas fired heaters. In no simulation were CO2 concentrations below industry recommended concentrations (1540 ppm), but alternative heating devices could reduce CO2 to acceptable concentrations. While this investigation does not represent all production swine farrowing barns, which differ in characteristics including room dimensions and swine occupancy, the simulation model and ventilation optimization methods can be applied to other production sites. This work shows that ventilation may be a cost-effective control option in the swine industry to reduce exposures.

Exposure to inhalable dust and endotoxin among Danish pig farmers affected by work tasks and stable characteristics

OBJECTIVE

To identify working tasks and stable characteristics that determine intensity and variability of personal exposure to dust and endotoxin among pig farmers.

METHODS

Three hundred fifty-four personal full-shift measurements were performed in 231 farmers employed in 53 Danish pig farms. Filters were gravimetrically analysed for inhalable dust and for endotoxin by the Limulus amebocyte lysate assay. Information on working tasks and stable characteristics were collected using self-reported activity diaries and walk-through surveys performed in conjunction with the measurements. Associations between log-transformed dust and endotoxin exposure and working tasks and stable characteristics were examined using linear mixed-effects analysis. In these models, worker and farm identity were treated as random effects and working tasks and stable characteristics as fixed effects. Both separate and combined models for tasks and stable characteristics were elaborated.

RESULTS

Inhalable dust concentrations ranged between 0.1 and 48 mg m(-3) and endotoxin concentrations varied between 9.2 and 370,000 EU m(-3). Field work activities played a dominant role on the exposure variability. Indoor working tasks with intense animal activity or handling of feed materials increased exposure concentrations, whereas engagement in field work was associated with lower exposure concentrations. High-pressure water cleaning increased endotoxin exposure but did not affect exposure to inhalable dust. Stable characteristics related to feeding practices and type of ventilation were determinants of exposure to inhalable dust. For endotoxin, the most important determinants were use of dry feed and slatted floor coverage. Feeding practices solely explained all between-farms variability in exposure to inhalable dust and endotoxin.

CONCLUSIONS

These findings suggest feeding systems, flooring and ventilation to be potential areas where improved methods can reduce exposure to dust and endotoxin among pig farmers. Further, they highlight particular tasks involving feeding and intense animal handling as sources of very high levels of exposure. The pig farming industry is encouraged to focus on exposure reduction. Use of respirators during performance of working tasks where levels of exposure are particularly high ought to be considered until adequate hygienic solutions have been established.

Association of Toll-like receptor 2 gene polymorphisms with lung function in workers in swine operations

BACKGROUND

Workers in swine operations are exposed to indoor dusts and gases and are at increased risk of respiratory problems. Toll-like receptor (TLR) 2 recognizes ligands from gram-positive bacteria, whereas TLR4 responds to endotoxin from gram-negative bacteria.

OBJECTIVE

To investigate the effects of TLR2 and TLR4 polymorphisms on lung function in workers from swine operations and nonfarming rural dwellers.

METHODS

A total of 374 full-time workers from large swine operations and 411 nonfarming rural dwellers from Saskatchewan were included. Information on demography, lifestyle, and occupation, lung function measurements, and blood samples for genotyping were obtained from the participants. Multiple regression analysis and Bonferroni correction were used in the statistical analysis.

RESULTS

Workers with TLR2-16933T/A polymorphism (AA) had significantly greater mean values of lung function than workers with wild-type genotypes (AT+TT) after controlling for potential confounders (forced expiratory volume in 1 second, 3.7 vs 3.5 L; P=.009; forced expiratory flow between 25% and 75%, 3.7 vs 3.3 L; P=.003; predicted forced expiratory volume in 1 second; 100.3% vs 95.6%; P=.005; forced expiratory flow between 25% and 75%, 92.4% vs 83.4%; P=.009). These results were also observed for TLR2Arg677Trp polymorphism among the workers. No such significant differences were observed among nonfarming rural dwellers. For Asp299Gly and Thr399Ile polymorphisms in the TLR4 gene, no significant differences were observed in the mean lung function values between the polymorphic and wild-type groups in both workers and rural dwellers.

CONCLUSION

Our study is the first, to our knowledge, to report protective effects of TLR2 polymorphisms on lung function among workers in swine operations and raises the possibility that TLR2 polymorphisms are protective of airway disease in individuals exposed to gram-positive organisms in the inhaled airborne dust.

Does Training in Performing a Fit Check Enhance N95 Respirator Efficacy?

Fit testing of respirators has been recommended, legislated, and implemented in many countries. In the United States, the National Institute for Occupational Safety and Health advocates a fit check, or seal check, before donning a respirator for each fit test. The aim of this study was to investigate the relationship between respirator fitness and performance of the fit check upon donning a respirator. Eighty-four first-year undergraduate nursing students were selected for this study; they were divided randomly into four groups. None had performed a fit test or fit check before being recruited for this study. The real-time self-developed fit test method was used to measure the ambient air particle concentration outside and inside the respirator. Results showed significant differences between groups trained to perform the fit check and those untrained. The overall fit factors were higher in the two groups trained to perform the fit check. The overall fit factors were lower in the two groups not trained to do the fit check. N95 respirators are designed to form a tight seal against wearers' faces. Each time workers don respirators, they should evaluate proper fit. Training wearers in how to fit check increases the likelihood that they will adjust respirators to proper fit.

The Saskatchewan rural health study: an application of a population health framework to understand respiratory health outcomes

Background

Respiratory disease can impose a significant burden on the health of rural populations. The Saskatchewan Rural Health Study (SRHS) is a new large prospective cohort study of ages 6 and over currently being conducted in farming and non-farming communities to evaluate potential health determinants associated with respiratory outcomes in rural populations. In this article, we describe the rationale and methodology for the adult component.

The study is being conducted over 5 years (2009–15) in two phases, baseline and longitudinal. The baseline survey consists of two components, adults and children. The adult component consists of a questionnaire-based evaluation of individual and contextual factors of importance to respiratory health in two sub populations (a Farm Cohort and a Small Town Cohort) of rural families in Saskatchewan Rural Municipalities (RMs). Clinical studies of lung function and allergy tests are being conducted on selected sub-samples of the two cohorts based on the positive response to the last question on the baseline questionnaire: “Would you be willing to be contacted about having breathing and/or allergy tests at a nearby location?”. We adopted existing population health theory to evaluate individual factors, contextual factors, and principal covariates on the outcomes of chronic bronchitis, chronic obstructive pulmonary disease, asthma and obstructive sleep apnea.

Findings

Of the RMs selected to participate, 32 (89%) out of 36 RMs and 15 (94%) out of 16 small towns within the RMs agreed to participate. Using the mail out survey method developed by Dillman, we obtained completed questionnaires from 4264 households (8261 individuals). We obtained lung function measurements on 1609 adults, allergy skin test information on 1615 adults; both measurements were available on 1549 adults. We observed differences between farm and non-farm rural residents with respect to individual, contextual factors and covariates.

Discussion

There are differences between farm and non-farm rural residents with respect to individual and contextual factors and other variables of importance. The findings of the SRHS will improve knowledge of respiratory disease etiology, assist in the development and targeting of prevention programs, and in planning health services with farm and small town populations.

Organic dust toxic syndrome at a grass seed plant caused by exposure to high concentrations of bioaerosols

We describe an outbreak of sudden health problems in workers at a Danish grass seed plant after exposure to a particularly dusty lot of grass seeds. The seeds are called problematic seeds. The association between development of organic dust toxic syndrome (ODTS) and the handling of grass seeds causing exposure was assessed in a four-step model: (i) identification of exposure source, (ii) characterization of the emission of bioaerosols from the problematic and reference seeds, (iii) personal and stationary exposure measurement at the plant and (iv) repeated health examinations. The grass seeds were identified as the exposure source; the emissions of some bioaerosol components were up to 10(7) times higher from the problematic seeds than from reference seeds. Cleaning of the seeds was not enough to sufficiently reduce the high emission from the problematic seeds. Emission in terms of dust was 3.4 times as high from the problematic cleaned seeds as from cleaned reference seeds. The personal exposure reached 3 × 10(5) endotoxin units m(-3), 1 × 10(6) colony-forming units (cfu) of thermophilic actinomycetes m(-3), 8 × 10(5) cfu of Aspergillus fumigatus m(-3) and 9 × 10(6) hyphal fragments m(-3). Several workers working with the problematic seeds had symptoms consistent with ODTS. The most severe symptoms were found for the workers performing the tasks causing highest exposure. Respiratory airway protection proved efficient to avoid development of ODTS. Work with reference seeds did not cause workers to develop ODTS. Exposure was during work with the problematic seeds higher than suggested occupational exposure limits but lower than in studies where researchers for some minutes have repeated a single task expected to cause ODTS. In this study, many different bioaerosol components were measured during a whole working day. We cannot know, whether it is the combination of different bioaerosol components or a single component which is responsible for the development of ODTS. In conclusion, workers developed specific health symptoms due to the high bioaerosol exposure and were diagnosed with ODTS. Exposure to high concentrations of endotoxin, actinomycetes, fungi, hyphal fragments, β-glucan, and A. fumigatus occurred when working with a dusty lot of grass seed. Suspicion should be elicited by seeds stored without being properly dried and by seeds producing more dust than usually.

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.

Lung function and inflammation during murine Pseudomonas aeruginosa airway infection

BACKGROUND

Following any acute irritation lung function declines rapidly. Reasons for pulmonary deterioration in humans had been attributed to the action of either interleukin-6 or interleukin-8 in the lungs.

OBJECTIVES

The present study investigates the association between immune response and decline in lung function in a murine bacterial lung infection model.

METHODS

Upon intratracheal inoculation of C57BL/6J mice with a sublethal dose of Pseudomonas aeruginosa lung function, cytokine, chemokine and cytometry in bronchoalveolar lavage fluid, bacterial counts and lung histology was assessed at 2, 4, 6, 8, 10, 12, 18, 24, 48, 72, 96 and 120 h post inoculation.

RESULTS

Lung function measured by non-invasive head-out spirometry decreased most strongly between 6 and 10 h post inoculation and required up to 72 h to recover for selected parameters. CFU counts in the lungs peaked at 4h post inoculation with subsequent decline until at 24-48 h post inoculation background levels were reached. Cytokine and chemokine responses could be separated into an early pro-inflammatory phase (2-8h post inoculation; mainly tumor-necrosis factor α (TNFα) and interleukin-1α driven) and a late anti-inflammatory resolution phase (starting at 24h post inoculation; mainly interleukin-10 and interleukin-4 driven). Interleukin-6 levels correlated with the deterioration of lung function. Lung histology showed maximal changes in terms of inflammation and edema between 24 and 48 h post inoculation.

CONCLUSIONS

In summary, elevated interleukin-6, high local neutrophil counts and lung edema were found to be the most characteristic signs of the transient period of deterioration of lung function.

Respiratory issues in beef and pork production: recommendations from an expert panel

This paper summarizes "Respiratory Issues in Confined Feeding Operations," a panel discussion at the Agricultural Safety and Health Council of America/National Institute for Occupational Safety and Health conference, "Be Safe, Be Profitable: Protecting Workers in Agriculture," Dallas/Fort Worth, Texas, January 27-28, 2010. Occupational exposure to confined animal feeding operations is associated with cough, wheezing, and shortness of breath. Published data shows that 20% to 40% of hog confinement workers experience such symptoms, although most are able to continue working in this industry. Endotoxin is one component of hog barn dust that is associated with respiratory disease in workers. Endotoxin levels on cattle feedlots can also be in the range linked with occupational lung disease. The cattle industry has not yet prepared guidance documents for producers, in part because much less is known about the prevalence of lung disease in its workers. However, the pork industry provides information for pork producers on reducing their respiratory health risks through a multifaceted approach, including the use of respirators. Some jobs cannot be done safely without respiratory protection, such as entering manure pits. It is less clear for other jobs when respirators should be worn. Use of respiratory protection should be considered but not mandated for all persons working in close proximity to livestock in dusty conditions. A respiratory protection program may also serve as a cost effective biosecurity measure to protect animals from human pathogens such as influenza virus. Proper design and management of barn ventilation systems is critical for maintaining temperature and humidity levels for optimal animal growth; as well as decreasing the level of gases and respirable dusts. The pork and the cattle industries support occupational health and safety; however, the governmental guidance and recommendations for such programs are limited for the agricultural industries as a whole. The industries should lead the way in the effort to improve respiratory protection for workers. Overall, a team approach that includes input from managers, workers, and veterinarians is important for the reduction of respiratory hazards on livestock farms.

Gender-related tumor necrosis factor-alpha responses in naïve volunteers with Toll-like receptor 4 polymorphisms exposed in a swine confinement facility

The aim of this work is to better understand the responses of people that are exposed to agricultural organic dust and other factors in modern swine production. We investigated the effects of toll-like receptor 4 (TLR4) genotype and gender on respiratory responses of naïve volunteers (18-28 years) to swine barn exposure. Non-smoking healthy subjects (16 men and 13 women) with TLR4 299 (Asp299Gly) and/or 399 (Thr399Ile) polymorphisms (TLR4 299/399) and age-sex matched subjects with TLR4 wild-type alleles spent 5 h in a nonexposed environment (baseline day) and 5 h in a swine facility (exposure day). The results showed significant decreases between baseline and exposure days in across-shift forced vital capacity (FVC), forced expiratory volume in 1 second (FEV(1)), forced midexpiratory flow rate (FEF(25-75)), and FEV(1)/FVC ratio and in methacholine concentration that reduced FEV1 by 20% (PC(20)) in all groups; however, there were no differences by sex or genotype. Similarly, nasal cytokines, serum cytokines, and blood neutrophil count increased after exposure; in contrast, however, these were influenced by gender. The increase in serum tumor necrosis factor-alpha (TNF-alpha) between baseline and exposure was gender-dependent with male sex associated with a significant increase in the wild-type group and female sex associated with a significant increase in the polymorphic group. These results suggest that for persons exposed to a swine facility, one's immunological response varies with gender as well as TLR4 genotype.

Fractionation of swine barn dust and assessment of its impact on the respiratory tract following repeated airway exposure

The effects of repeated exposure to a range of doses of swine barn dust (SBD) on airway hyperresponsiveness (AHR) and inflammation were evaluated using a mouse model system. A number of components, including endotoxin and a number of feed proteins, were identified in SBD, and mice were exposed 20 min/d for 14 d to a log dilution series of nebulized SBD suspensions. AHR to methacholine was measured using head-out whole-body plethysmography, and the methacholine concentration inducing a 20% decrease in pulmonary airflow (PC(20) MCh) was calculated. At the end of the 14-d exposure period, bronchoalveolar lavage (BAL) fluids were recovered, cytokines (interleukin [IL]-1beta, IL-6, keratinocyte-derived chemokine [KC], and tumor necrosis factor [TNF]) in BAL were measured by enzyme-linked immunosorbent assay (ELISA), and leukocytes in BAL were counted. The PC(20) MCh was significantly lower in the group of mice that were exposed to the highest concentration of SBD than in controls or the group exposed to the lowest level of dust. Likewise, the group that was exposed to the highest level of SBD had significantly higher levels of IL-1beta, KC, and TNF than controls and some other groups. There were substantially more lymphocytes and monocytes in the BAL from mice that were exposed to the higher levels of SBD for the 14-d period, but neutrophils were not a part of this response. The SBD exposures used in these experiments induced chronic inflammatory phenotype responses, as indicated by the predominance of lymphocytes and monocytes, but not neutrophils, in BAL and by inflammatory cytokines detected. The association between the PC(20)MCh and dose of SBD suggests that a threshold of susceptibility occurs after a relatively low, chronic exposure to SBD.

Reciprocal association between atopy and respiratory symptoms in fully employed female, but not male, workers in swine operations

In large commercial swine operations, workers are exposed to indoor air-contaminants during their work-shift. In recently developed large swine operations, exposures are typically 8 or 12 hours/day and females account for a sizeable proportion of the workers. Implications of enhanced exposures and gender require evaluation. Two hundred and forty male and 134 female swine barn workers and 184 male and 227 female nonfarming rural dwellers (controls) (mean age +/- SD males: 36.2 +/- 11.9; females: 34.9 +/- 10.7) completed respiratory questionnaires. Of these, 348 workers (93.0%) and 401 controls (97.6%) underwent allergy skin prick tests (house dust mite, Alternaria sp., hog, cat, mixed grass). The number of hours worked per day was 8.2 for female workers and 7.7 for male workers. Atopy was present in 38.7% and 29.4% of male and female workers, and 46.9% and 38.3% of male and female controls. There was a 72% reduction in risk for chronic phlegm and 70% reduction in usual phlegm in female workers with atopy in comparison to female controls without atopy. There was a significantly increased risk for chronic and usual phlegm, and chronic and usual cough in male workers with atopy. Female workers with atopy were at increased risk for asthma. These findings, that atopy in exposed female workers may be protective of symptoms suggestive of chronic bronchitis but that atopic female workers may be more susceptible to the development of asthma, suggest that exposures to inhaled substances in the workplace may be mediated differently in male and female workers.

An aerobiological perspective of dust in cage-housed and floor-housed poultry operations

The Canadian poultry production industry contributes nearly $10 billion to the Canadian economy and employs nearly 50,000 workers. However, modern poultry facilities are highly contaminated with airborne dust. Although there are many bioaerosols in the poultry barn environment, endotoxin is typically attributed with the negative respiratory symptoms observed in workers. These adverse respiratory symptoms have a higher prevalence in poultry workers compared to workers from other animal confinement buildings. Workers in cage-housed operations compared to floor-housed facilities report a higher prevalence of some respiratory symptoms. We review the current state of knowledge on airborne dust in poultry barns and respiratory dysfunction in poultry workers while highlighting the areas that need further investigation. Our review focuses on the aerobiological pathway of poultry dust including the source and aerosolization of dust and worker exposure and response. Further understanding of the source and aerosolization of dust in poultry operations will aid in the development of management practices to reduce worker exposure and response.

Toll-like receptor 4 variants reduce airway response in human subjects at high endotoxin levels in a swine facility

BACKGROUND

Toll-like receptor 4 (TLR4) variants have been shown to reduce the respiratory responses to inhaled LPS in controlled experiments among healthy volunteers.

OBJECTIVE

We sought to investigate whether naive subjects with TLR4 variants showed reduced respiratory response to a complex aerosol including endotoxin as a major constituent.

METHODS

Twenty-nine nonsmoking, nonatopic healthy subjects with TLR4 299/399 polymorphisms and 29 age- and sex-matched, wild-type TLR4 control subjects were exposed for 5 hours each in a noncontaminated environment (baseline day) and in a swine confinement facility (exposure day). There were 16 men and 13 women in each of the 2 age- and sex-matched groups.

RESULTS

TLR4 polymorphic subjects who were exposed to high endotoxin levels (>or=1550 EU/m(3)) had less reduction in the percentage across-shift change in FEV(1) from baseline than did wild-type subjects exposed to similar endotoxin levels. Among subjects exposed to higher endotoxin levels, the mean differences in the percentage across-shift changes between baseline and exposure days were significantly less in TLR4 polymorphic subjects compared with those seen in wild-type subjects in FEV(1) (-8.48% +/- 1.52% [mean +/- SE] vs -11.46% +/- 1.79%, P = .001), forced expiratory flow between 25% and 75% of forced vital capacity (-18.30% +/- 1.99% vs -24.14% +/- 3.28%, P = .009), and FEV(1)/forced vital capacity ratio (-5.40% +/- 0.56% vs -8.53% +/- 1.51%, P = .04). These patterns were not observed in IL-6 levels from serum and nasal lavage fluid, IL-8 levels from nasal lavage fluid, white blood cell counts, or blood differential counts.

CONCLUSION

The association between TLR4 variants and reduced airway responsiveness to inhaled particulate was observed at high endotoxin concentrations, creating the possibility of certain threshold phenomena for the apparent protective effect of TLR4 variants.

Behavior change, environmental hazards and respiratory protection among a southern farm community

The agricultural industry ranks as one of the most dangerous in terms of occupational deaths and injuries. A wide variety of respiratory illnesses can result from the exposure to grain and organic dusts and working in animal confinement facilities and barns. This article analyzes the Transtheoretical Model of Change for implications relevant to health promotion and education. This study explored differences of perception of occupational health, environmental exposures, and stages of change consistent with the readiness to take action and the confidence to act toward respiratory health among farmers who report respiratory symptoms with physical activity and those who do not. A convenience sample of 123 farm owners and agricultural employees recruited from community-based agricultural events in southeast and central Louisiana completed three surveys: (a) Health Risk and Environmental Assessment; (b) Identification of Respiratory Mask Use; (c) Stage of Awareness and Preventive Respiratory Health; and demographic information. Subjects performed pulmonary function tests including three Forced Vital Capacity (FVC) maneuvers while connected to a Renaissance spirometer. Even though the majority of subjects rated themselves in action stage of change, subjects reported using respiratory protective devices less than 10% of the time. No significant differences were found in environmental exposures. Using chi-square analysis, those farmers who reported breathlessness were significantly more likely to report fatigue, chest pain, and dizziness. Those farmers who report breathlessness are significantly less likely to perceive respiratory health as important compared to other occupational illnesses/conditions. There is a need for additional studies to further examine the relationship between respiratory symptoms, exposure risks, and behavior change theory.

Role of Toll-like receptor 4 in lung inflammation following exposure to swine barn air

The authors tested a hypothesis that lung inflammation and airway hyperresponsiveness (AHR) induced following barn air exposure are dependent on Toll-like receptor 4 (TLR4) by exposing C3HeB/FeJ (intact TLR4, wild type [WT]) and C3H/HeJ (defective TLR4, mutant) mice either to the barn air (8 hours/day for 1, 5, or 20 days) or ambient air. Both strains of mice, compared to their respective controls, showed increased AHR following 5 exposures but dampened AHR after 20 exposures to show lack of effect of TLR4 on AHR. However, swine barn air induced lung inflammation with recruitment of inflammatory cells and cytokine expression was observed in WT but not in mutant mice. These data show different roles of TLR4 in lung inflammation and AHR in mice exposed to swine barn air.

Respiratory manifestations and respiratory diseases: prevalence and risk factors among pig farmers in Braço do Norte, Brazil

OBJECTIVE

To describe the prevalence of signs and symptoms of respiratory disease among pig farmers in Braço do Norte, Santa Catarina, Brazil, evaluating the characteristics of swine confinement buildings and identifying potential risk factors.

METHODS

An exploratory, cross-sectional, observational study involving interviews and pulmonary function tests (spirometry). Aspects related to job history, work conditions, and environment, as well as to respiratory status and smoking, were evaluated. Odds ratios were used to estimate the chances of exposure when comparing pig farmers according to the signs and symptoms of respiratory disease.

RESULTS

The prevalence of clinical signs and symptoms of respiratory disease was 84.3%, clinical manifestations of bronchial asthma were detected in 5.6% of the farmers evaluated, and chronic bronchitis was diagnosed in 5.1% of the workers over the age of 40. Only 2.6% used specific individual respiratory protection devices. Respiratory disease was positively associated with low socioeconomic level, low level of education, smoking, the use of wood stoves, and the use of disinfectants. Work load and length of employment were both apparently associated with a lower prevalence of respiratory disease.

CONCLUSION

The association between duration of employment and lower prevalence of respiratory disease can be attributed to the healthy worker effect. However, the evident respiratory impairment among pig farmers and the limited use of personal protective equipment draw attention to the need to implement a program to monitor exposure and regulate environmental factors.

In vitro production of tumor necrosis factor-alpha by human monocytes stimulated with lipopolysaccharide is positively correlated with increased blood monocytes after exposure to a swine barn

Recently there has been interest in the air quality in and around intensive livestock production facilities, such as modern swine production barns, where agricultural workers and surrounding residents may be exposed to elevated levels of organic dusts. The health effects of these exposures are not completely understood. The study that is reported here is a component of a larger investigation of the relationships among the acute effects of high-concentration endotoxin exposure (swine barn dust), polymorphisms in the TLR4 gene, and respiratory outcomes following exposure to swine confinement buildings. The relationships among a mediator of acute lung inflammation, tumor necrosis factor alpha (TNF-alpha), and clinical responses to acute swine barn exposure were characterized. Analysis of the results showed that in vitro stimulation of human monocytes with as little as 1 ng/ml of lipopolysaccharide (LPS) produced a significant increase in the monocytes that produced TNF-alpha. Although the proportion of TNF-alpha-positive monocytes after in vitro stimulation with 1 ng/ml of LPS was not associated with gender or TLR4 genotype, it was positively associated with the concentration of monocytes in blood after barn exposure. Thus, these two responses to different forms of LPS exposure are significantly correlated, and more responsive monocytes in vitro indicate a forthcoming relative monocytosis, post barn exposure, which may initiate a cascade of chronic inflammation.

Lung function and farm size predict healthy worker effect in swine farmers

BACKGROUND

Swine farmers are exposed to a number of airborne contaminants associated with respiratory ill health.

OBJECTIVES

To examine the factors associated with healthy worker effect in the swine industry from a longitudinal follow-up of farmers at 4 years and 13 years.

DESIGN

A prospective study of swine farmers and nonexposed rural residents was conducted using similar questionnaires and same spirometer at each time point.

RESULTS

In the original observations in 1990/1991, we studied 302 swine farmers and 261 nonfarming control subjects. Four years later in 1994/1995, 217 swine farmers and 171 nonfarming control subjects of the original group participated again. In 2003/2004, 163 swine farmers and 118 control subjects were retested. Of the 163 swine farmers, 52 remained active swine farmers and 111 were no longer swine farming, thus providing the opportunity to evaluate work continuity in the industry. Among farmers studied in 2003/2004, mean values for percentage of predicted FEV(1)/FVC ratio and forced expiratory flow between 25% and 75% of FVC were lower in those who had quit swine farming compared to those still swine farming and nonfarming control subjects. The herd size in the barn at baseline in 1990/1991 and at interim follow-up in 1994/1995 was a significant predictor of quitting swine farming. In addition, percentage of predicted FEV(1)/FVC at the interim observation was a significant predictor of quitting swine farming.

CONCLUSIONS

There is a significant healthy worker effect among swine farmers. The continuation of work in the facilities may be predicted by herd size and interim lung function.

Excess respiratory symptoms in full-time male and female workers in large-scale swine operations

BACKGROUND

The respiratory health effects of working in swine operations have been previously investigated mainly in male owner/operators with intermittent exposure to indoor air contaminants.

OBJECTIVES

To examine the respiratory health of male and female workers employed full time in large-scale intensive swine operations in Saskatchewan.

DESIGN

A cross-sectional study of male and female swine workers employed full time and nonfarming control subjects.

RESULTS

In total, 374 swine farmers (240 men and 134 women) and 411 nonfarming rural control subjects (184 men and 227 women) participated in the study. After controlling for age and smoking, male and female workers were significantly more likely to have chronic and usual cough, and chronic and usual phlegm in comparison to male and female nonfarming control subjects, respectively. The risks of these symptoms were greater in female workers (chronic cough: odds ratio [OR], 5.14; 95% confidence interval, 2.67 to 9.89; chronic phlegm: OR, 4.26; 95% confidence interval, 1.86 to 9.73) than in male workers (chronic cough: OR, 3.47; 95% confidence interval, 1.77 to 6.81; chronic phlegm: OR, 3.22; 95% confidence interval, 1.76 to 5.89). These increased risks were not observed for asthma and asthma-like symptoms in female workers. Male workers had an increased risk of shortness of breath in comparison to their nonfarming counter parts.

CONCLUSIONS

Swine workers had increased risk of chronic and usual bronchitis-like symptoms. Female workers in swine operations appear to have greater risk of these symptoms. Future surveillance programs should include both male and female workers.

Asthma symptoms among adolescents who attend public schools that are located near confined swine feeding operations

OBJECTIVES

Little is known about the health effects of living in close proximity to industrial swine operations. We assessed the relationship between estimated exposure to airborne effluent from confined swine feeding operations and asthma symptoms among adolescents who were aged 12 to 14 years.

METHODS

During the 1999-2000 school year, 58169 adolescents in North Carolina answered questions about their respiratory symptoms, allergies, medications, socioeconomic status, and household environments. To estimate the extent to which these students may have been exposed during the school day to air pollution from confined swine feeding operations, we used publicly available data about schools (n = 265) and swine operations (n = 2343) to generate estimates of exposure for each public school. Prevalence ratios and 95% confidence intervals for wheezing within the past year were estimated using random-intercepts binary regression models, adjusting for potential confounders, including age, race, socioeconomic status, smoking, school exposures, and household exposures.

RESULTS

The prevalence of wheezing during the past year was slightly higher at schools that were estimated to be exposed to airborne effluent from confined swine feeding operations. For students who reported allergies, the prevalence of wheezing within the past year was 5% higher at schools that were located within 3 miles of an operation relative to those beyond 3 miles and 24% higher at schools in which livestock odor was noticeable indoors twice per month or more relative to those with no odor.

CONCLUSIONS

Estimated exposure to airborne pollution from confined swine feeding operations is associated with adolescents' wheezing symptoms.

Acute blood neutrophilia induced by short-term compost dust exposure in previously unexposed healthy individuals

OBJECTIVES

Systemic effects of organic dust inhalation have been described in farming environments. The purpose of this study was to examine whether a single exposure at a biowaste composting facility could also exert systemic effects in healthy volunteers not previously exposed to organic dust from such facilities.

METHODS

Seventeen subjects (age 20-35 years) were exposed to organic dust for 2 h (exposure day) during moderate exercise; 12 of these subjects also took part in a control experiment (control day). Spirometry was performed before and immediately after the exposure. White blood cell counts and levels of tumor-necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) in peripheral blood were determined before and 3 h after exposure.

RESULTS

Exposures did not result in significant changes in lung function or blood cytokine levels. In contrast, the number and percentage of neutrophils increased during the exposure day [median (range) percent change of percentages 14 (-2; 67) %; P=0.002], but not during the control day [5 (-22; 35) %; P=0.66). Furthermore, there was a decrease in the number and percentage of eosinophils during the exposure day [-47 (-57; 0.0) %; P=0.002], whereas the change during the control day was smaller [-8 (-56; 71) %; P=0.68].

CONCLUSION

Short-term exposure of healthy, young subjects to organic dust from composting facilities had opposite effects on the numbers of blood neutrophils and blood eosinophils. These effects, though mild, suggest that even during a limited period of moderate work a sufficient amount of bioactive material can be deposited in the lung to elicit acute systemic alterations.

Multiple exposures to swine barn air induce lung inflammation and airway hyper-responsiveness

Background

Swine farmers repeatedly exposed to the barn air suffer from respiratory diseases. However the mechanisms of lung dysfunction following repeated exposures to the barn air are still largely unknown. Therefore, we tested a hypothesis in a rat model that multiple interrupted exposures to the barn air will cause chronic lung inflammation and decline in lung function.

Methods

Rats were exposed either to swine barn (8 hours/day for either one or five or 20 days) or ambient air. After the exposure periods, airway hyper-responsiveness (AHR) to methacholine (Mch) was measured and rats were euthanized to collect bronchoalveolar lavage fluid (BALF), blood and lung tissues. Barn air was sampled to determine endotoxin levels and microbial load.

Results

The air in the barn used in this study had a very high concentration of endotoxin (15361.75 ± 7712.16 EU/m³). Rats exposed to barn air for one and five days showed increase in AHR compared to the 20-day exposed and controls. Lungs from the exposed groups were inflamed as indicated by recruitment of neutrophils in all three exposed groups and eosinophils and an increase in numbers of airway epithelial goblet cells in 5- and 20-day exposure groups. Rats exposed to the barn air for one day or 20 days had more total leukocytes in the BALF and 20-day exposed rats had more airway epithelial goblet cells compared to the controls and those subjected to 1 and 5 exposures (P < 0.05). Bronchus-associated lymphoid tissue (BALT) in the lungs of rats exposed for 20 days contained germinal centers and mitotic cells suggesting activation. There were no differences in the airway smooth muscle cell volume or septal macrophage recruitment among the groups.

Conclusion

We conclude that multiple exposures to endotoxin-containing swine barn air induce AHR, increase in mucus-containing airway epithelial cells and lung inflammation. The data also show that prolonged multiple exposures may also induce adaptation in AHR response in the exposed subjects.

Partial protection by respirators on airways responses following exposure in a swine house

BACKGROUND

Exposure to swine dust leads to an intense airway inflammation and increased bronchial responsiveness. The purpose of the present study was to evaluate the effect of a respiratory protection device during exposure in a swine house.

METHODS

Twenty-two subjects, 11 with a respirator, were exposed. Symptoms, body temperature, nasal lavage, and a bronchial metacholine challenge were performed before and 7 hr after exposure. For exposure assessment a nasal sampler was evaluated.

RESULTS

The subjects with a respirator showed an attenuated inflammatory nasal response. An increase in bronchial responsiveness was observed in both groups, significantly greater in the unprotected group. The use of respirators reduced endotoxin exposure by more than 90% (assessed by nasal samplers).

CONCLUSION

The use of a respirator attenuated the inflammatory response compared with an unprotected group. The minor effect on bronchial responsiveness suggests that gases and/or ultrafine particles may also be important factors.

Evaluation of a respiratory health program for farmers and their families

Occupational exposures to organic dusts, gases, welding fumes and agricultural chemicals result in farmers' increased risk of respiratory health problems compared to other workers. The Respiratory Health Program for Saskatchewan farmers addresses the difficulties of delivering an occupational health program to a sparsely distributed population on the Prairies. We summarized their pulmonary function and respiratory health by spirometry and questionnaire respectively. The necessity of the program was demonstrated by the frequency of lower than predicted pulmonary function tests and referrals to family physicians (1996 through 1999). Age, years in farming, usual cough, wheezing on most days and nights, bringing up phlegm from the chest, breathlessness, and cigarette smoking were associated significantly with pulmonary function results. We evaluated the Respiratory Health Program (1994 through 2000) with respect to acceptability, accessibility, appropriateness, continuity, effectiveness, efficiency, and risk/safety by using questionnaires and evaluations by farm families.

Airways inflammation after exposure in a swine confinement building during cleaning procedure

BACKGROUND

Healthy volunteers exposed for 3 hr during weighing of pigs develop an airway inflammation characterized by a massive influx of neutrophilic granulocytes in the upper and lower airways and increased bronchial responsiveness to methacholine. The purpose of the present study was to investigate health effects from exposure during cleaning of the swine confinement building and to evaluate the effect of a respiratory protection device.

METHODS

Sixteen subjects were exposed for 3 hr during cleaning of a swine confinement room with a high-pressure cleaner. Seven out of sixteen subjects were equipped with a mask during exposure.

RESULTS

The bronchial responsiveness increased in all subjects following exposure, significantly more in the group exposed without a mask (P < 0.05). The cell concentration (mainly neutrophilic granulocytes) in nasal lavage fluid as well as the concentration of interleukin-8, increased significantly only in those subjects exposed without a respiratory protection device. In peripheral blood, an increase of neutrophilic granulocytes was observed in both groups, although it was significantly higher in the group without mask (P < 0.05). The inhalable dust level was 0.94 (0.74 - 1.55) mg/m(3) and respirable dust 0.56 (0.51-0.63) mg/m(3).

CONCLUSION

Exposure to dust aerosols during the cleaning of the interior of a swine confinement building induces increased bronchial responsiveness and an acute inflammatory reaction in the upper airways. The use of a mask attenuated but did not abolish the inflammatory response. This suggests that gases and/or ultrafine particles in this environment could be important factors in the development of increased bronchial responsiveness.

Review: occupational and environmental lung disease

Occupational and environmental lung disease is a vast topic. Therefore, this review focuses on areas that represent new clinical insights that have not been addressed recently in Current Opinion in Pulmonary Medicine. The topics are considered important for the future and emphasize diseases that strike large numbers of people or exposures that affect large segments of the population. This review highlights literature published between the years 2000 to 2001 related to air pollution, occupational asthma, lung diseases in agricultural workers, nylon flock workers lung disease, pneumoconiosis, and environmental exposure to biomass smoke, including environmental tobacco smoke. These publications highlight the changing world of occupational and environmental lung diseases. Traditionally, this field dealt with chronic diseases caused by very high levels of exposure to materials that affected virtually all workers to a similar degree. Disease could be recognized readily by characteristic symptoms, signs, and radiographic abnormalities. Dose-effect relationships were usually clear, and the solution to disease was generally to limit exposure for all workers. This approach served well for conditions such as coal workers pneumoconiosis or toxic responses to chlorine gas. The new world of occupational and environmental lung diseases often involves low levels of exposure to complex mixtures of materials that produce nonspecific or intermittent symptoms in a subgroup of exposed individuals. Interactions between genetic susceptibility, concomitant tobacco smoke exposure, and co-morbid diseases hugely complicate both diagnosis and prevention. New tools, and possibly new thought paradigms, are needed to detect, treat, and prevent occupational and environmental lung diseases in a changing world.