Respiratory effects of bioaerosols: exposure-response study among salmon-processing workers.

OBJECTIVES: The aim of the study was to determine exposure-response relationships in salmon-processing workers. METHODS: Cross-shift FEV1, acute respiratory symptoms, and exposure to total protein, parvalbumin and endotoxin were main variables measured during one workweek. Exposure-response relationships were analyzed by Generalized Estimation Equations of cross-week data and by multiple regressions of day-to-day data. RESULTS: Exposure levels were higher in those workers who reported use of water hose. GEE showed negative coefficients for interaction between TP exposure and time (days) on cross-week change of FEV1. Multiple regressions showed significant associations between TP levels and cross-shift change of FEV1 and symptoms (cough, chest tightness) only for Monday shifts. CONCLUSIONS: A tolerance effect during the course of a workweek is suggested. Use of water hose is a risk process with regard to the liberation of measured components of bioaerosols.

Exposure to parvalbumin allergen and aerosols among herring processing workers.

BACKGROUND: There are increasing reports of allergies and respiratory symptoms among workers in the fish processing industry, coinciding with an increasing use of high-pressure water in the processing plants. However, few studies have measured exposure in these work environments. OBJECTIVES: The aim of this study was to characterize the occupational exposure of workers to herring antigen and to screen environmental factors at a herring (Clupea harengus) plant in which new and more encapsulated filleting machines had been installed. To assist in this, a method to assess airborne exposure to herring allergen was needed. METHODS: Exposure to airborne herring antigen, mould spores, and endotoxin were measured during work. Antigen exposure was assessed using a newly developed sensitive (detection limit, 0.1 ng ml(-1)) rabbit polyclonal sandwich enzyme-linked immunosorbent assay against the major herring muscle protein allergen, parvalbumin. Aerosols were measured by mass concentration (DataRAM) and number of particles (Climet I-500). RESULTS: Personal geometric mean herring allergen exposure was 986 ng m(-3) at the old filleting workstations and 725 ng m(-3) at the new workstations (difference not significant). Outside the production room, the level was ~130 ng m(-3). Number of particles and mass concentration were both significantly lower around the new machines than around the old machines (P < 0.001 and P < 0.0001, respectively). The highest particle count was seen for the 0.3-0.5 µm fraction, with more than 400,000 particles per cubic metre air. Endotoxin concentration in the air varied between 3 and 92 EU m(-3), with the highest levels when the catch mainly contained herring that had eaten krill or seaweed. CONCLUSIONS: We developed a sensitive method to detect herring antigen. High exposure to herring antigen was measured during filleting work. The particles in the air around the fillet machines were mainly <0.5 µm and the newer encapsulated machines generated fewer particles. It is important to reduce occupational exposure of workers to aerosols by improving the ventilation system, machines, and organization of work.

Salmon allergen exposure, occupational asthma, and respiratory symptoms among salmon processing workers.

BACKGROUND: This investigation was triggered by three cases of asthma-about 10% of the workforce-occurring in a salmon processing plant over a short period of time. The aim of the investigation was to characterize the work exposure of inhalable organic particles with personal measurements. Respiratory symptoms at work among workers were also assessed. METHODS: Exposures to airborne salmon allergen, airborne mold spores, and endotoxin in water and air were measured during work. To assess the Atlantic salmon (Salmo salar) Sal s 1 allergen exposure a polyclonal sandwich enzyme-linked immunosorbent assay (ELISA) was developed. Current workers (n = 26) answered questionnaires and underwent allergy and lung function tests. RESULTS: Using the sensitive ELISA method (0.05 ng/ml), we found that workers were exposed to high levels of salmon major allergen at the filleting machine and at the filleting table. Airborne endotoxin levels were low, and mold levels were elevated. Only the three initial asthma cases had IgE to salmon. Of the other workers, 65% reported respiratory symptoms at work. These had lower pulmonary function than workers without such symptoms. CONCLUSIONS: We developed a sensitive method to measure salmon antigen in air and found that filleting workers were most exposed. It is important to reduce aerosols by improving the ventilation system, machines and organization of work since respiratory symptoms at work among workers were common.

Rapid one-step assays for on-site monitoring of mouse and rat urinary allergens.

Allergy to rodent proteins is common among laboratory animal workers. Sensitive methods to measure exposure to these allergens have been developed. These assays are, however, expensive, time-consuming, and require a laboratory facility and methodological expertise. A simple method to screen for allergen spread, or to test whether hygiene standards are maintained, would be useful. Lateral flow immunoassays (LFIAs) are especially suited for field settings; the tests are simple and results are visible within minutes. LFIAs were developed for detection of the rodent urinary allergens Mus m 1 and Rat n 1. Pilot studies were performed in animal facilities in three countries using both extracts from airborne dust samples and samples collected by wiping surfaces. For comparison and determination of sensitivity, the concentrations of rodent urinary allergens in the samples were also measured using enzyme immunoassays (EIAs). The LFIAs for rat and mouse urinary allergens had a detection limit of 31 pg allergen per mL in a buffer system with purified allergen standards. Results of environmental dust extracts tested in LFIAs correlated well with levels obtained using EIAs. Spread of rodent allergens, or non-adherence to hygiene around laboratory animal facilities, may aggravate rodent allergy. Using a simple, sensitive one-step assay, allergens can be detected to prevent allergen exposure. The results reveal that the rapid assays are suited for on-site demonstration of exposure to rodent allergens, and thus, useful in occupational hygiene practice.

Assay of air sample eluates.

After air sampling and elution, the air sample eluate contains an unknown amount of allergens together with other materials. The proteins of interest can be quantified using immunoassays, which are sensitive, economical, and can be used for high throughput. However, the amount of antigen or allergen in an air sample may be very low and consequently the assays must be very sensitive and specific. Immunoassays use antibodies both to capture and visualize the chosen antigen. High specificity and sensitivity can best be achieved by the use of purified, characterized, and specific antibodies. It is possible to choose between a wide variety of assay setups and reagents. The method described here has been developed for the measurement of airborne rodent allergens. It is a noncompetitive, two-site (sandwich) EIA that utilizes polyclonal antibodies. The detection system uses biotin and streptavidin for increased sensitivity and horseradish peroxidase as the substrate with 3,3',5,5'-tetramethylbenzidine (TMB) for rapid color development and high sensitivity.

Nasal air sampling for measuring inhaled wheat allergen in bakeries with and without facemask use.

OBJECTIVE: Occupational asthma caused by flour is common in bakers. We applied novel intranasal air samplers (INAS) to assess wheat allergen exposure and evaluate respiratory protection in bakeries. METHODS: Two models of INAS (INAS-M1 and INAS-M2) were compared with simultaneous personal air sampling of inhalable dust, both with and without facemasks. Wheat allergen levels were measured using a sensitive sandwich enzyme immunoassay. Allergenic particles were immunostained for microscopic visualization. RESULTS: Personal air sampling correlated well with INAS-M1 (r = 0.89) and INAS-M2 (r = 0.75). INAS-M2 collected particles more effectively than INAS-M1. Facemasks reduced inhalation of wheat allergen by 96% and 93% measured using INAS-M1 and INAS-M2, respectively. CONCLUSIONS: Nasal air sampling can complement personal air sampling to measure short-term exposure and evaluate respiratory protection. To prevent baker's asthma, facemasks may be an effective solution in addition to improving workplaces.

Airborne cat allergen reduction in classrooms that use special school clothing or ban pet ownership.

BACKGROUND: Allergens from furred animals are brought to school mainly via clothing of pet owners. Asthmatic children allergic to cat have more symptoms when attending a class with many cat owners, and some schools allocate specific resources to allergen avoidance measures. OBJECTIVE: The aim of the current study was to evaluate the effect of school clothing or pet owner-free classes compared with control classes on airborne cat allergen levels and to investigate attitudes and allergic symptoms among the children. METHODS: Allergen measurements were performed prospectively in 2 classes with school clothing, 1 class of children who were not pet owners, and 3 control classes during a 6-week period in 2 consecutive years. Portable pumps and petri dishes were used for collection of airborne cat allergen, and a roller was used for sampling on children's clothes. Cat allergen (Fel d 1) was analyzed with enzyme-linked immunoassay and immunostaining. Both years, questionnaires were administered to the children. RESULTS: We found 4-fold to 6-fold lower airborne cat allergen levels in intervention classes compared with control classes. Levels of cat allergen were 3-fold higher on clothing of cat owners than of children without cats in control classes. Pet ownership ban seemed less accepted than school clothing as an intervention measure. CONCLUSION: For the first time, it has been shown that levels of airborne cat allergen can be reduced by allergen avoidance measures at school by using school clothing or pet ownership ban, and that both measures are equally efficient. The clinical effect of these interventions remains to be evaluated.

Detection of mouse and rat urinary aeroallergens with an improved ELISA.

BACKGROUND: Risk analysis of laboratory animal work presupposes allergen monitoring with sensitive methods. Commercial ELISA kits have recently become available for the detection of mouse (Mus m 1) and rat (Rat n 1) urinary allergen from settled dust samples and air samples with high allergen levels. OBJECTIVE: Our aims were to enhance the sensitivities of the commercial ELISA kits for low aeroallergen levels (less than 1 ng/m(3)) and to test these methods with air samples collected from an animal facility. METHODS: Personal and stationary air samples were collected from an animal facility during various tasks of laboratory animal work and from various premises of the animal facility. RESULTS: The sensitivities of the ELISA assays were improved with a careful choice of analysis parameters and reagents. The detection limits of 0.1 ng/m(3) for Mus m 1 and 0.8 ng/m(3) for Rat n 1 were established. The sensitized assays enabled detection of mouse and rat aeroallergens also from premises in which animals or dirty cages were not present during sampling. CONCLUSION: These sensitive assays will help to perform risk assessment in laboratory animal work. However, there remains a lack of standardized analytic procedures and occupational exposure limits for laboratory animal allergens.

Exposure to airborne allergens: a review of sampling methods.

A number of methods are used to assess exposure to high-molecular weight allergens. In the occupational setting, airborne dust is often collected on filters using pumps, the filters are eluted and allergen content in the eluate analysed using immunoassays. Collecting inhalable dust using person-carried pumps may be considered the gold standard. Other allergen sampling methods are available. Recently, a method that collects nasally inhaled dust on adhesive surfaces within nasal samplers has been developed. Allergen content can be analysed in eluates using sensitive enzyme immunoassays, or allergen-bearing particles can be immunostained using antibodies, and studied under the microscope. Settling airborne dust can be collected in petri dishes, a cheap and simple method that has been utilised in large-scale exposure studies. Collection of reservoir dust from surfaces using vacuum cleaners with a dust collector is commonly used to measure pet or mite allergens in homes. The sampling methods differ in properties and relevance to personal allergen exposure. Since methods for all steps from sampling to analysis differ between laboratories, determining occupational exposure limits for protein allergens is today unfeasible. A general standardisation of methods is needed.

Reduction of exposure to laboratory animal allergens in a research laboratory.

OBJECTIVES: The purpose of this study was to determine exposure levels in the laboratory during different tasks and evaluate the effectiveness of safety equipment used to reduce personal exposure. METHODS: Personal and stationary air samples were collected during different tasks in a laboratory animal facility in which several allergen reduction strategies had been implemented. Mouse urinary allergen concentrations were measured using a polyclonal sandwich enzyme-linked immunosorbent assay. Sera from the personnel (n = 29) were analysed every 6 months for the presence of specific antibodies against mouse and rat urinary allergens, and the staff answered questionnaires on work-related symptoms, exposure and use of respiratory protection. RESULTS: The highest airborne mouse allergen levels were measured during manual emptying of cages, during changing of cages on an unventilated table and during handling of male animals on an unventilated table. Automatic emptying and cleaning of cages resulted in low airborne allergen levels in the working room. Using a ventilated cage-changing wagon reduced the allergen exposure level from 77 to 17 ng/m3. The housing of animals in ventilated cabinets, with air exhausted through the cabinet, effectively prevented the release of allergens into the ambient air. The handling of animals on ventilated benches and the use of a centralized vacuum cleaner resulted in a low exposure level. Only two subjects developed specific immunoglobulin E of > 0.35 kU/l, of whom one was reduced to negative after increased use of respiratory protection. CONCLUSIONS: Effective reduction of exposure to allergens can be achieved by several strategies, which together appear to minimize sensitization to rodents.