Laboratory animal allergy: an update

Association of fine particulate matter to allergic rhinitis: A systematic review and meta-analysis

Objective:

Fine particulate matter (PM2.5) has become a major concern for global environmental health, as it can lead to inflammatory diseases, such as allergic rhinitis (AR) and cause a high burden of disease. The aim of this study is to carry out a systematic review and meta-analysis based on available research to present the link between ambient PM2.5 and the risk of AR in global populations. Methods: We systematically searched six databases from their inception to 30 November 2020. An expanded literature search was carried out using the references of the included studies. Data extraction was performed using Excel 2016 software, and meta-analysis and heterogeneity analysis were performed using Review Manager 5.3 software. Results: A total of 14 out of 1361 studies were included in the meta-analysis. The quality assessment showed these studies to be of high quality. Seven out of 14 studies reported a relationship between ambient PM2.5 and AR through Odds ratios (OR, ORoverall = 1.14, 95% CI [1.00, 1.29]), but with a non-significant statistical overall test result (the test result for overall effect was Z = 1.98, p =.05). For subgroups by ages and regions, ORChildren = 1.08 (95% CI [1.04, 1.13]), and OROther ages = 1.50 (95% CI [1.24, 1.81]. The differences between age-related subgroups were significant (p <.01). Meanwhile, the relationship between PM2.5 and the risk of AR in Asia was significant (ORAsia = 1.20, 95% CI [1.01, 1.44], p =.001); whereas the association studies from outside of Asia have reported the relationship as non-significant (OROut-Asia = 1.04, 95% CI [0.82, 1.31], p =.76). Conclusion: There are reports that recognize that the exposure to PM2.5 may contribute to the development of AR. An international framework with a whole-of-society approach, including air quality control efforts and well-being health promotion among AR patients and at-risk populations, should be implemented.

The allergen Mus m 1.0102: Cysteine residues and molecular allergology

Mus m 1.0102 is a member of the mouse Major Urinary Protein family, belonging to the Lipocalins superfamily. Major Urinary Proteins (MUPs) are characterized by highly conserved structural motifs. These include a disulphide bond, involved in protein oxidative folding and protein structure stabilization, and a free cysteine residue, substituted by serine only in the pheromonal protein Darcin (MUP20). The free cysteine is recognized as responsible for the onset of inter- or intramolecular thiol/disulphide exchange, an event that favours protein aggregation. Here we show that the substitution of selected cysteine residues modulates Mus m 1.0102 protein folding, fold stability and unfolding reversibility, while maintaining its allergenic potency. Recombinant allergens used for immunotherapy or employed in allergy diagnostic kits require, as essential features, conformational stability, sample homogeneity and proper immunogenicity. In this perspective, recombinant Mus m 1.0102 might appear reasonably adequate as lead molecule because of its allergenic potential and thermal stability. However, its modest resistance to aggregation renders the protein unsuitable for pharmacological preparations. Point mutation is considered a winning strategy. We report that, among the tested mutants, C138A mutant acquires a structure more resistant to thermal stress and less prone to aggregation, two events that act positively on the protein shelf life. Those features make that MUP variant an attractive lead molecule for the development of a diagnostic kit and/or a vaccine.

Exposição prolongada a animais de laboratório está associada ao aumento de casos de asma

Resumo Objetivo: descrever o resultado do acompanhamento de trabalhadores sensibilizados a animais de laboratório que prolongaram sua exposição. Métodos: após um período de aproximadamente 7 anos, entramos em contato com todos os indivíduos com sensibilização alérgica ocupacional detectada em estudo anterior. Um questionário foi aplicado para situação ocupacional atual, relação entre alergia e a decisão de deixar o trabalho ou exposição e para asma, sibilância, rinite, sintomas cutâneos e dispneia noturna. Resultados: dos 74 indivíduos com sensibilização ocupacional, 45 responderam ao questionário na segunda avaliação e 37 ainda estavam expostos. Ao comparar os dados da primeira avaliação com os da avaliação atual, observou-se um aumento na frequência de asma. Na primeira avaliação, entre todos os sensibilizados (n = 74), 27,0% responderam sim a ambas as questões “Você tem ou já teve asma?” e “A asma foi diagnosticada por um médico?”. Na segunda avaliação, 7 anos depois, dos 37 sujeitos que ainda estavam expostos, 51,3% responderam sim a essas questões (OR: 2,80; IC95%: 1,23-6,38; p = 0,013). Não houve mudança na frequência de respostas positivas às outras perguntas. Conclusão: os dados demonstram aumento da frequência de asma entre trabalhadores com sensibilização ocupacional que prolongam a exposição a animais de laboratório.

How Working Tasks Influence Biocontamination in an Animal Facility

The exposure to biocontaminants in animal facilities represents a risk for developing infectious, allergic and toxic diseases. The aim of this study was to determine what factors could be associated with a high level of exposure to biological agents through the measure and characterization of airborne fungi, bacteria, endotoxin, (1,3)-β-d-glucan and animal allergens. Airborne microorganisms were collected with an air sampler and identified by microscopic and biochemical methods. Endotoxin, (1,3)-β-d-glucan, Mus m 1, Rat n 1, Can f 1, Fel d 1, Equ c 4 allergens were detected on inhalable dust samples by Kinetic LAL, Glucatell, and ELISA assays, respectively. Our data evidenced that changing cages is a determinant factor in increasing the concentration of the airborne biocontaminants; the preparation of bedding and distribution of feed, performed in the storage area, is another critical working task in terms of exposure to endotoxins (210.7 EU/m3) and (1,3)-β-d-glucans (4.3 ng/m3). The highest concentration of Mus m 1 allergen (61.5 ng/m3) was observed in the dirty washing area. The detection of expositive peaks at risk of sensitization (>2 μg/g) by Fel d 1 in animal rooms shows passive transport by operators themselves, highlighting their role as vehicle between occupational and living environments.

A robust method for the estimation and visualization of IgE cross-reactivity likelihood between allergens belonging to the same protein family

Among the vast number of identified protein families, allergens emanate from relatively few families which translates to only a small fraction of identified protein families. In allergy diagnostics and immunotherapy, interactions between immunoglobulin E and allergens are crucial because the formation of an allergen-antibody complex is necessary for triggering an allergic reaction. In allergic diseases, there is a phenomenon known as cross-reactivity. Cross-reactivity describes a situation where an individual has produced antibodies against a particular allergenic protein, but said antibodies fail to discriminate between the original sensitizer and other similar proteins that usually belong to the same family. To expound the concept of cross-reactivity, this study examines ten protein families that include allergens selected specifically for the analysis of cross-reactivity. The selected allergen families had at least 13 representative proteins, overall folds that differ significantly between families, and include relevant allergens with various potencies. The selected allergens were analyzed using information on sequence similarities and identities between members of the families as well as reports on clinically relevant cross-reactivities. Based on our analysis, we propose to introduce a new A-RISC index (Allergens’–Relative Identity, Similarity and Cross-reactivity) which describes homology between two allergens belonging to the same protein family and is used to predict the likelihood of cross-reactivity between them. Information on sequence similarities and identities, as well as on the values of the proposed A-RISC index is used to introduce four categories describing a risk of a cross-reactive reaction, namely: high, medium-high, medium-low and low. The proposed approach can facilitate analysis in component-resolved allergy diagnostics, generation of avoidance guidelines for allergic individuals, and help with the design of immunotherapy.

Biological occupational allergy: Protein microarray for the study of laboratory animal allergy (LAA)

Background

Laboratory Animal Allergy (LAA) has been considered a risk for the workers since 1989 by the NIOSH. About one third of the Laboratory Animal Workers (LAWs) can manifest symptoms to LAA as asthma, rhinitis, conjunctivitis and cutaneous reactions. The prevalence of LAA-induced clinical symptoms has been estimated with a great variability (4-44%) also due to the different methodologies applied.

Objective

Evaluate the prevalence of IgE positivity to mouse and rat allergens in LAWs and assess which factors are predisposing to sensitization among subjects exposed to laboratory animals in the workplace.

Methods

One hundred LAWs were invited to fill out a questionnaire regarding current allergic symptoms, atopic history, home environment, previous and current occupational history. IgE reactivity versus specific allergens was evaluated with ImmunoCAP ISAC.

Results

Out of one hundred LAWs, 18% had a serum susceptibility to mouse and/or rat allergens and 42% reported to have occupational allergy symptoms. Combining the results acquired by ImmunoCAP ISAC and questionnaire, 17% of LAWs have been defined as LAWs-LAA positive since they present a positive IgE response and allergy symptoms, 1% LAWs-LAA sensitized, 25% LAWs-LAA symptomatic and 57% LAWs-LAA negative. Presence of previous allergy symptoms in work and life environment were significantly related to LAWs-LAA positive/sensitized.

Conclusions

The study aimed to define the immunological profile of LAWs using the proteomic array as an innovative approach in the study of environmental and occupational exposure to allergens. We suggested a definition of LAWs-LAA considering serum IgE response and presence of allergy symptoms. The proposed approach has the advantage to provide a standard methodology for evaluating the specific IgE responsiveness to animal allergens in specific workplace also considering the immunological profile of workers referred to exposure in life and occupational environment.

Laboratory Animal Bite Anaphylaxis: A National Survey: Part 1: Case Series and Review of the Literature

OBJECTIVE

This study documents previously unreported cases of laboratory animal bite anaphylaxis in animal laboratory facilities in the United States.

METHODS

An online survey was e-mailed to designated institutional officials at laboratory animal facilities identified by the National Institutes of Health Office of Laboratory Animal Welfare.

RESULTS

One hundred ninety eight organizations responded and 15 organizations indicated that workers had experienced anaphylaxis following an animal bite. Case report forms were completed by nine of these institutions for 14 cases, 13 for rodent bites, and one involving a needlestick from a horse. In half of the cases involving rodents, there was no prior history of animal allergy. All workers had uncomplicated recoveries. Treatment, testing, and work restrictions varied across cases.

CONCLUSIONS

While uncommon, anaphylaxis from laboratory animal bites occurs more frequently than suggested by the literature.

Laboratory Animal Bite Anaphylaxis: A National Survey: Part 2: Treatment Protocols

OBJECTIVE

This study documents current treatment protocols for laboratory animal bite anaphylaxis in the United States.

METHODS

An online survey was e-mailed to designated institutional officials at laboratory animal facilities identified by the National Institutes of Health Office of Laboratory Animal Welfare.

RESULTS

One hundred eighty-nine organizations responded to the question of whether they had a treatment protocol with 32% indicating that they had a protocol. Having a case of anaphylaxis increased the likelihood of having a protocol (61%). Of those with a protocol, 58% included treatment with injectable epinephrine, if clinically indicated. Among all respondents, only 14% reported keeping injectable epinephrine at the location where animal work is performed.

CONCLUSIONS

A minority of responding organizations had protocols in place to address laboratory animal bite anaphylaxis. Organizations with workers at risk should consider implementing a protocol for assessment and treatment.

Laboratory animal allergy reduction from 2001 to 2016: An intervention study

Exposure to laboratory animals (LA) can cause allergic sensitization and symptoms as rhinitis, conjunctivitis, asthma, anaphylaxis and dermatitis. In 2000, a program was instituted at Trieste Universities to decrease LA allergy among scientists and technicians working with animals. The aim of our study was to investigate LA allergy in workers exposed to LA from 2001 to 2016, and to verify the effects of a preventive program. Four hundred sixty seven people underwent pre-employment screening for a job with laboratory animals at Universities of Trieste consisting in a medical examination, a full respiratory and allergy anamnesis, using a standardized questionnaire, skin prick test with common and occupational allergens, and spirometry. Every year, each worker repeated the medical examination and underwent again tests and questionnaire. Each worker can ask for a medical examination and skin prick test, in case of unset of symptoms. Logistic multivariate analysis and generalized equation estimation were use, to verify factors associated to LA allergy. Sensitization to LA decreased in years, going from 25.6% in 2001-2004 to 8.2% in 2013-2016 (p < 0.001). Multivariate logistic regression analysis confirmed the role of atopy by prick test (OR = 6; IC95% 2.2-16.6), of common allergic symptoms (OR = 2.9; IC95% 1.4-6.39) and of calendar periods. No association was found between LA allergy, years, and hours of exposure. Our study demonstrated a significant reduction of LA allergy after the application of a preventive program.

Occupational Animal Allergy

PURPOSE OF REVIEW

This review explores animal allergen exposure in research laboratories and other work settings, focusing on causes and prevention.

RECENT FINDINGS

(1) Consistent with the hygiene hypothesis, there is new evidence that early childhood exposure to pets produces changes in the gut microbiome that likely lead to a lower risk of allergy. (2) Anaphylaxis from laboratory animal bites occurs more frequently than suggested by prior literature. (3) Animal allergens represent an occupational hazard in a wide variety of work settings ranging from fields that work with animals to public settings like schools and public transportation where allergens are brought into or are present in the workplace. Exposure to animal allergens can result in allergy, asthma, and anaphylaxis. Animal allergy has been most studied in the research laboratory setting, where exposure reduction can prevent the development of allergy. Similar prevention approaches need to be considered for other animal work environments and in all settings where animal allergens are present.

Allergic sensitization to laboratory animals is more associated with asthma, rhinitis, and skin symptoms than sensitization to common allergens

BACKGROUND

Workers exposed to laboratory animals have a high risk of developing laboratory animal allergy (LAA). Atopy seems to be the main risk factor for LAA. We hypothesized that occupational sensitization is a better predictor for the development of asthma, rhinitis, and bronchial hyperresponsiveness (BHR) than common sensitization.

OBJECTIVE

To investigate the association between occupational sensitization to laboratory animals and clinical outcomes.

METHODS

This was a cross-sectional study performed at two universities on students and employees dealing with small rodents. The subjects were allocated in groups: non-sensitized, common sensitization, or occupational sensitization, according to the results of the skin prick test (SPT). All subjects answered a questionnaire about animal exposures, symptoms, allergic diseases, and underwent spirometry and bronchial challenge test with mannitol. Multivariate analysis was performed using Poisson regression to estimate the prevalence ratio (PR).

RESULTS

Data from 453 volunteers were analysed. Non-sensitized group comprised 237 subjects; common sensitization group, 142 subjects; and occupational sensitization group, 74 subjects. Occupational sensitization was associated with greater risk for all outcomes studied. When the common sensitization group was reference, skin symptoms had PR of 1.36, 95% confidence interval (CI): 1.01-1.85; wheezing had PR of 1.75, CI 95%: 1.21-2.53; rhinitis had PR of 1.25, 95%: 1.11-1.40; nocturnal dyspnoea had PR of 2.40, 95% CI: 1.31-4.40; bronchial hyperresponsiveness (BHR) had PR of 2.47, 95% CI: 1.50-4.09; and confirmed asthma had PR of 2.65, 95% CI: 1.45-4.85. In addition, the overlap of asthma, rhinitis, and skin symptoms in a same subject was significantly more prevalent in the occupational sensitization group, 16.2% versus 4.9% in the common sensitization group.

CONCLUSION AND CLINICAL RELEVANCE

Occupational sensitization is associated with allergic symptoms and respiratory diseases. SPT with occupational allergens along with other parameters may contribute to detection of risk for allergic and respiratory diseases associated with exposure to laboratory animals.

Impact of environmental microbiota on human microbiota of workers in academic mouse research facilities: An observational study

Objectives

To characterize the microbial environment of workers in academic mouse research facilities using endotoxin, 16S qPCR, and 16S amplicon sequencing. To determine whether the work microbiome contributes to the human microbiome of workers.

Methods

We performed area air sampling from the animal rooms, dirty, middle, and setup cage wash locations in four academic mouse research facilities. 10 workers in the dirty cage wash area underwent personal air sampling as well as repeated collection of nasal, oral, and skin samples before and after the work shift. Environmental samples underwent measurement of endotoxin, mouse allergen, bacteria copy number via 16S qPCR, and microbial identification via 16S rDNA sequencing. 16S rDNA sequencing was also performed on human samples before and after the work shift. SourceTracker was used to identify the contribution of the work microbiome to the human microbiome.

Results

Median endotoxin levels ranged from undetectable to 1.0 EU/m³. Significant differences in mouse allergen levels, bacterial copy number, microbial richness, and microbial community structure were identified between animal, dirty, middle, and setup cage wash locations. Endotoxin levels had only a moderate correlation with microbial composition. Location within a facility was a stronger predictor of microbial community composition (R² = 0.41, p = 0.002) than facility. The contribution of the work microbiome to the pre-shift human microbiome of workers was estimated to be 0.1 ± 0.1% for the oral microbiome; 3.1 ± 1.9% for the nasal microbiome; and 3.0 ± 1.5% for the skin microbiome.

Conclusions

The microbial environment of academic animal care facilities varies significantly by location rather than facility. Endotoxin is not a proxy for assessment of environmental microbial exposures using 16S qPCR or 16S rDNA sequencing. The work microbiome contributes to the composition of the nasal and skin microbiome of workers; the clinical implications of this observation should be further studied.

Procedures of Necropsy and Tissue Sampling

Necropsy is a major step of most studies using laboratory animals. During necropsy, tissue and organ noticeable grossly changes should be recorded and critical tissue samples may be stored for the subsequent evaluation. It is therefore important that the personnel in charge of this key experimental step to be adequately trained and aware of the study endpoints.

Anaphylaxis in laboratory workers because of rodent handling: two case reports

Introduction:

Occupational allergy to rodents among laboratory animal workers is common. Most patients generally experience allergic symptoms after the first few years of work. Associated symptoms are usually mild, such as rhinoconjunctivits, urticaria, and asthma. Anaphylaxis, although rare, could be severe and life threatening.

Methods:

We have described in this study two cases of laboratory workers that developed skin and respiratory reactions following laboratory rat and mouse bites, consistent with anaphylaxis.

Results:

Skin testing was found positive for rat epithelium in the patient with anaphylaxis due to rat bite. Elevated levels of specific IgE antibodies against rat and mouse epitheliums were also detected in both the patients.

Conclusion:

These cases illustrate a severe hypersensitivity reaction that could potentially occur in occupational workers that are in close contact with rodents. Reduction of allergen exposure, regular screening, and job modification could be beneficial for affected individuals. Health care workers should be made aware that anaphylaxis could be a serious consequence of laboratory animal bites, particularly in those already sensitized.

Study of risk factors for atopic sensitization, asthma, and bronchial hyperresponsiveness in animal laboratory workers

OBJECTIVES

The aim of this estudy was to investigate the influence of allergen exposure levels and other risk factors for allergic sensitization, asthma, and bronchial hyperresponsiveness (BHR) in workers exposed to laboratory animals.

METHODS

This was a cross-sectional study performed at two universities, 123 workplaces with 737 subjects. Dust samples were collected from laboratories and animal facilities housing rats, mice, guinea pigs, rabbits, or hamsters and analyzed by enzyme-linked immunosorbent assay (ELISA) to measure allergen concentrations. We also sampled workplaces without animals. Asthma was defined by both symptoms and BHR to mannitol. The concentrations of allergens were tested for association with a skin prick test, respiratory symptoms, spirometry data, and BHR. This multivariate analysis was performed by using Poisson regression to estimate the relative risk (RR) for the exposed group.

RESULTS

Our sample comprised students and workers, with 336 subjects in the nonexposed group and 401 subjects in the exposed group. Sixty-nine subjects (17%) had positive results in the skin prick test for animal allergens in the exposed group; in the nonexposed group, 10 subjects had positive results (3%) (p<0.001). Exposure to laboratory animals over 2.8 years was associated with atopic sensitization (RR=1.85; 95% confidence interval: 1.09-3.15; p=0.02). Allergen concentration was not associated with sensitization, asthma, or BHR.

CONCLUSION

Exposure to laboratory animals was associated with atopic sensitization. However, we did not find a cutoff allergen concentration that increased the risk for sensitization. Duration of exposure seems to be more relevant to sensitization than concentration of allergens in dust.

[Cockroaches and co. The role of health pests as allergen source]

In most of the cases health pests are carriers of pathogens or parasites which have a negative impact on human health or affect the health of other mammals. What is lesser known is that they can also act as allergens. Most of the health pests in this sense belong to the arthropods, such as cockroaches (Blattaria), mosquitos (Culiciformia), lice (Pediculus humanus corporis), fleas (Siphonaptera) and ticks (Argasidae). In the group of vertebrates rats (Rattus norvegicus and Rattus rattus), house mice (Mus musculus) and pigeons (Columba livia domestica) are also classified as health pests. Also storage pests which are not carriers of pathogens can induce secondary infestation with hygiene pests or molds and have an underestimated impact on human health. In this article selected examples of health pests and also storage pests as an allergen source are described, taking into account the sensitization prevalence and identified single allergens.

Occupational asthma: an overview

Occupational asthma is a form of asthma that is often under-diagnosed and under-reported. Unrecognized occupational asthma can lead to progression of disease and increased morbidity. The medical history is a critical element for establishing a diagnosis of OA. The history should include a detailed assessment of the workplace environment, the work process, changes in symptoms in and away from the workplace, and a review of relevant material safety data sheets that may provide clues regarding exposure(s) and the potential cause(s). Objective testing including spirometry pre- and post-bronchodilators, peak expiratory flow rate monitoring in and out of the workplace, provocation testing (i.e., methacholine challenge) to assess for airway hyperresponsiveness, and, if feasible, specific provocation by experienced personnel in a controlled setting to a suspected inciting agent are necessary for confirming a diagnosis. Skin or serologic testing for specific IgE to aeroallergens to assess the worker's atopic status is useful especially when considering certain forms of OA where atopy is a risk factor. Specialized laboratory testing may be useful for specific OA causes. It is important to correctly make the diagnosis of OA as the impact on the worker's future employment and earning power can be significantly affected.

Animal allergens and their presence in the environment

Exposure to animal allergens is a major risk factor for sensitization and allergic diseases. Besides mites and cockroaches, the most important animal allergens are derived from mammals. Cat and dog allergies affect the general population; whereas, allergies to rodents or cattle is an occupational problem. Exposure to animal allergens is not limited to direct contact to animals. Based on their aerodynamic properties, mammalian allergens easily become airborne, attach to clothing and hair, and can be spread from one environment to another. For example, the major cat allergen Fel d 1 was frequently found in homes without pets and in public buildings, including schools, day-care centers, and hospitals. Allergen concentrations in a particular environment showed high variability depending on numerous factors. Assessment of allergen exposure levels is a stepwise process that involves dust collection, allergen quantification, and data analysis. Whereas a number of different dust sampling strategies are used, ELISA assays have prevailed in the last years as the standard technique for quantification of allergen concentrations. This review focuses on allergens arising from domestic, farm, and laboratory animals and describes the ubiquity of mammalian allergens in the human environment. It includes an overview of exposure assessment studies carried out in different indoor settings (homes, schools, workplaces) using numerous sampling and analytical methods and summarizes significant factors influencing exposure levels. However, methodological differences among studies have contributed to the variability of the findings and make comparisons between studies difficult. Therefore, a general standardization of methods is needed and recommended.

Animal allergens and their presence in the environment

Exposure to animal allergens is a major risk factor for sensitization and allergic diseases. Besides mites and cockroaches, the most important animal allergens are derived from mammals. Cat and dog allergies affect the general population; whereas, allergies to rodents or cattle is an occupational problem. Exposure to animal allergens is not limited to direct contact to animals. Based on their aerodynamic properties, mammalian allergens easily become airborne, attach to clothing and hair, and can be spread from one environment to another. For example, the major cat allergen Fel d 1 was frequently found in homes without pets and in public buildings, including schools, day-care centers, and hospitals. Allergen concentrations in a particular environment showed high variability depending on numerous factors. Assessment of allergen exposure levels is a stepwise process that involves dust collection, allergen quantification, and data analysis. Whereas a number of different dust sampling strategies are used, ELISA assays have prevailed in the last years as the standard technique for quantification of allergen concentrations. This review focuses on allergens arising from domestic, farm, and laboratory animals and describes the ubiquity of mammalian allergens in the human environment. It includes an overview of exposure assessment studies carried out in different indoor settings (homes, schools, workplaces) using numerous sampling and analytical methods and summarizes significant factors influencing exposure levels. However, methodological differences among studies have contributed to the variability of the findings and make comparisons between studies difficult. Therefore, a general standardization of methods is needed and recommended.

Prevalence of occupational allergy in medical researchers exposed to laboratory animals

Allergy to laboratory animals is a well known occupational hazard and remains a health concern for individuals in contact with lab animals. This study evaluates the prevalence of allergy symptoms among medical researchers exposed to laboratory animals. We analyzed data from a cross-sectional survey, involving subjects (n=169, 21-59 yr), working in Kochi Medical School, Japan. They were asked to fill out a questionnaire to evaluate symptoms related to contact with laboratory animals. The overall response rate was 86.2%. The prevalence of laboratory animal allergy was 17.6%. The symptoms most reported were allergic rhino-conjunctivitis and asthma. A small number of the subjects received education on the allergy issue and 62.5% of subjects with an allergy to laboratory animals claimed to have atopy. Protection from animal allergens should be a high priority for institutions using lab animals; providing continuous education to animal handlers would be meaningful to reduce and control exposure.

The characteristics, treatment and prevention of laboratory animal allergy

Laboratory animal allergy (LAA) is a pervasive problem that affects up to one-third of laboratory animal personnel. An immediate hypersensitivity reaction can be triggered by contact with antigens present in urine, hair, dander and saliva of laboratory animals. The authors provide an overview of the epidemiology, triggering mechanisms, diagnosis, treatment and risk factors of LAA. They also discuss primary and secondary prevention measures that can be taken to reduce LAA morbidity and to allow personnel suffering from LAA to safely continue to do their jobs.

Serum albumins-unusual allergens

BACKGROUND

Albumins are multifunctional proteins present in the blood serum of animals. They can bind and transport a wide variety of ligands which they accommodate due to their conformational flexibility. Serum albumins are highly conserved both in amino acid sequence and three-dimensional structure. Several mammalian and avian serum albumins (SAs) are also allergens. Sensitization to one of the SAs coupled with the high degree of conservation between SAs may result in cross-reactive antibodies in allergic individuals. Sensitivity to SA generally begins with exposure to an aeroallergen, which can then lead to cross-sensitization to serum albumins present in food.

SCOPE OF REVIEW

This review focuses on the allergenicity of SAs presented in a structural context.

MAJOR CONCLUSIONS

SA allergenicity is unusual taking into account the high sequence identity and similarity between SA from different species and human serum albumin. Cross-reactivity of human antibodies towards different SAs is one of the most important characteristics of these allergens.

GENERAL SIGNIFICANCE

Establishing a relationship between sequence and structure of different SAs and their interactions with antibodies is crucial for understanding the mechanisms of cross-sensitization of atopic individuals. Structural information can also lead to better design and production of recombinant SAs to replace natural proteins in allergy testing and desensitization. Therefore, structural analyses are important for diagnostic and treatment purposes. This article is part of a Special Issue entitled Serum Albumin.

Laboratory animals and respiratory allergies: the prevalence of allergies among laboratory animal workers and the need for prophylaxis

OBJECTIVE

Subjects exposed to laboratory animals are at a heightened risk of developing respiratory and allergic diseases. These diseases can be prevented by simple measures such as the use of personal protective equipment. We report here the primary findings of the Laboratory Animals and Respiratory Allergies Study regarding the prevalence of allergic diseases among laboratory animal workers, the routine use of preventive measures in laboratories and animal facilities, and the need for prevention programs.

METHODS

Animal handlers and non-animal handlers from 2 Brazilian universities (University of São Paulo and State University of Campinas) answered specific questionnaires to assess work conditions and symptoms. These subjects also underwent spirometry, a bronchial challenge test with mannitol, and skin prick tests for 11 common allergens and 5 occupational allergens (rat, mouse, guinea pig, hamster, and rabbit).

RESULTS

Four hundred fifty-five animal handlers (32±10 years old [mean±SD], 209 men) and 387 non-animal handlers (33±11 years old, 121 men) were evaluated. Sensitization to occupational allergens was higher among animal handlers (16%) than non-animal handlers (3%, p<0.01). Accessibility to personal protective equipment was measured at 85% (median, considering 73 workplaces of the animal handler group). Nineteen percent of the animal handlers indicated that they wear a respirator at all times while handling animals or working in the animal room, and only 25% of the animal handlers had received an orientation about animal-induced allergies, asthma, or rhinitis.

CONCLUSION

In conclusion, our data indicate that preventive programs are necessary. We suggest providing individual advice to workers associated with institutional programs to promote a safer work environment.

Occupational asthma

Occupational asthma is the most common occupational lung disease. Work-aggravated asthma and occupational asthma are two forms of asthma causally related to the workplace, while reactive airways dysfunction syndrome is a separate entity and a subtype of occupational asthma. The diagnosis of occupational asthma is most often made on clinical grounds. The gold standard test, specific inhalation challenge, is rarely used. Low molecular weight isocyanates are the most common compounds that cause occupational asthma. Workers with occupational asthma secondary to low molecular weight agents may not have elevated specific IgE levels. The mechanisms of occupational asthma associated with these compounds are partially described. Not all patients with occupational asthma will improve after removal from the workplace.

Prevention of laboratory animal allergy in the United States: a national survey

OBJECTIVE

Respiratory allergy to laboratory animals is a common and preventable occupational health problem. This study documents current laboratory animal allergy (LAA) prevention programs in the United States.

METHODS

An online survey was e-mailed to designated institutional officials at laboratory animal facilities identified by the National Institutes of Health Office of Laboratory Animal Welfare.

RESULTS

A total of 198 organizations responded and more than 80% required the use of uniforms and gloves to control exposure. Respirators were required by 25% of organizations. Medical surveillance was mandated by 58% of organizations (70% for organizations with at least 100 employees working with animals). Work restriction practices varied. Only 25% of organizations reported knowing the prevalence (range: 0% to 75%) and 29% reported knowing the incidence of LAA (range: 0% to 18%).

CONCLUSIONS

There is broad variation in policy and practice to prevent LAA. An evidence-based consensus would ensure greater protection of workers.

Angora wool asthma in textile industry

Up to now the exposures to hair and skin derivatives of animals have not yet been the subject of systematic studies. The observation of a clinical case has provided the opportunity for a review of the literature. The inpatient was a 49-year-old man, a carder in a textile factory, exposed to angora wool. He noticed the appearance of dyspnea during working hours. There was no eosinophilia in blood, and the results of pulmonary function tests were normal. The nonspecific bronchial provocation test with methacholine demonstrated an abnormal bronchial reactivity. The challenge test with angora wool was positive (decrease in FEV1 of more than 40%) as well as total IGE and specific IgE to rabbit epithelium (433 KU/l and 12.1 KUA/l, resp.). Several sources of allergens were found in the rabbit, and the main allergen was represented by proteins from epithelia, urine, and saliva. Most of these proteins belong to the family of lipocalin, they function as carriers for small hydrophobic molecules (vitamins and pheromones). If the diagnosis of occupational asthma caused by animal hair and skin derivatives may be relatively easy by means of the challenge test, defining etiology is complicated because of the lack of in vitro tests.

Occupational exposure to laboratory animals causing a severe exacerbation of atopic eczema

A 24-year-old man with a long history of severe atopic eczema presented with a marked exacerbation requiring hospital admission. It emerged that his occupation as an animal house technician required him to work closely with laboratory animals, particularly mice and rats. Radioallergosorbent tests to mice allergens were markedly elevated. Avoidance of animal work, in conjunction with medical treatment, resulted in a marked improvement of his eczema.

Necropsy and sampling procedures in rodents

Necropsy is a major step of most studies using laboratory animals. During necropsy, tissue and organ changes noticeable grossly can be recorded, and important tissue samples can be stored for subsequent evaluation. It is therefore important that the personnel in charge of this key experimentation step be adequately trained and aware of the study endpoints.

Role of mouse allergens in allergic disease

Mouse allergen has long been recognized as an important cause of occupational allergy and asthma, but only recently has it been implicated in asthma and allergic diseases in community settings. Recent studies have established that mouse allergen is detectable in most US homes, with strikingly high levels in some inner cities. Inner city homes in major northeastern and midwestern US urban centers have levels as much as 100-fold higher than those found in other geographic regions. In addition, about 25% of inner city children with asthma have evidence of IgE sensitization to mouse. Several studies have shown that the combination of sensitization and exposure to higher levels of mouse allergen is associated with substantial asthma morbidity, including hospitalizations. Integrated pest management is efficacious in reducing mouse allergen levels and is recommended for sensitized patients with asthma. However, its impact on clinical outcomes has not yet been proven.

Implementing a medical surveillance program for animal care staff

In animal research facilities, personnel may develop allergies or serious health problems as a result of exposure to chemical or biological agents. Medical surveillance is essential for evaluating the health of prospective or current employees and determining their risk of exposure to occupational hazards. The author discusses the role of institutional medical surveillance programs and presents considerations for implementing such programs.

Exposure to mouse allergen in U.S. homes associated with asthma symptoms

BACKGROUND

Most studies investigating the role of residential mouse allergen exposures in asthma have focused on inner-city populations.

OBJECTIVE

We examined whether elevated mouse allergen levels were associated with occupants' asthma status in a nationally representative sample of U.S. households.

METHODS

Data for this study were collected as part of the National Survey of Lead and Allergens in Housing. This cross-sectional study surveyed 831 housing units inhabited by 2,456 individuals in 75 different locations throughout the United States. The survey obtained information on demographics, household characteristics, and occupants' health status by questionnaire and environmental observations. We used a polyclonal immunoassay to assess concentrations of mouse urinary protein (MUP) in vacuumed dust collected from various indoor sites.

RESULTS

Of the surveyed homes, 82% had detectable levels of MUP, and in 35% of the homes, MUP concentrations exceeded 1.6 microg/g, a level that has been associated with increased mouse allergen sensitization rates. Current asthma, defined as having doctor-diagnosed asthma and asthma symptoms in the preceding 12 months, was positively associated with increased MUP levels. The observed association was modified by atopic status; in allergic individuals, elevated MUP levels (>1.6 microg/g) increased the odds of having asthma symptoms [adjusted OR=1.93; 95% confidence interval (CI), 1.14-3.27], but we found no association in those who did not report allergies (adjusted OR=0.69; 95% CI, 0.33-1.44).

CONCLUSIONS

In allergic asthma, residential mouse allergen exposure is an important risk factor for asthma morbidity.

Controlling occupational allergies in the workplace

OBJECTIVES

In recent years, the prevalence of work-related asthma has increased. Therefore, more attention needs to be paid to occupational allergens and their avoidance and control in workplaces. However, risk assessment of occupational allergen exposure is difficult because the relationship between exposure concentration, sensitization, and symptoms has not been fully established. This paper introduces a systematic and comprehensive approach to assessing and managing allergen risks at workplaces.

MATERIALS AND METHODS

This approach relies on the cooperation and active communication during the whole process between management, employees, and health care personnel, with the assistance of experts when needed. In addition to gathering background information, including allergic symptoms, through questionnaires addressed to the management and employees, hazard identification is also processed in the workplace through observations and measurements. The methods generally recommended to reduce allergen exposure are compared with those used in the workplace. The process is to be carefully planned and documented to allow later follow-up and re-evaluation.

RESULTS

The multi-faceted approach encompasses several risk assessment techniques, and reveals the prevalence of work-related allergic symptoms. The process effectively focuses on the potential means for controlling allergen exposure.

CONCLUSION

Based on this approach, the synopsis on the critical points that require implementation of effective control measures can be presented.

Laboratory animal allergy: an occupational hazard

Laboratory animal allergy is a relatively common work-related condition occurring in an estimated one-third of laboratory animal workers. More than 10% of these workers develop occupational asthma. Sensitization often occurs in the first 3 years of employment. Risk factors include a personal or family history of atopy, other preexisting non-work-related allergies, and a significant exposure to laboratory animals. Inhalation is the most common route of exposure, followed by skin and eye exposures. Preplacement testing and regular health surveillance screening may be used by institutions employing laboratory animal workers to identify, monitor, and prevent allergies and disease in these workers. Intervention and prevention techniques (i.e., engineering, administrative, and work practice controls and personal protective equipment) are key to controlling and preventing allergy symptoms and occupational asthma. Occupational health professionals play an important role in the early identification of at-risk and affected employees, and can render the necessary treatment, referrals, education, and recommendations to prevent debilitating illness.

Occupation and adult-onset asthma among Chinese women in a population-based cohort

BACKGROUND

Exposure to industrial irritants is believed to have contributed to the increasing prevalence of asthma worldwide. We examined the associations between occupation and asthma among women in a case-control study nested in the population-based Shanghai Women's Health Study cohort in China.

METHODS

Cases were 1,050 women who reported a physician-diagnosed asthma as adults. Controls were 4,200 women matched to the cases by year of birth and age at diagnosis. Lifetime occupational histories were obtained. Logistic regression was applied to estimate odds ratios (ORs) adjusting for smoking, education, family income, and concurrent chronic bronchitis.

RESULTS

Asthma is more prevalent in production industries for metal tools (OR = 2.4; 1.3-4.7), metal products for everyday use (OR = 1.6; 1.1-2.4), ships (OR = 2.6; 1.0-6.8), and clocks (OR = 1.9; 1.0-3.4), and in occupations as farm workers (OR = 4.0; 1.2-13.0), laboratory technicians and analyzers (OR = 2.2; 1.2-3.9), and installation and maintenance workers for weaving and knitting machineries (OR = 2.4; 1.1-5.4). Other associations less commonly reported were identified for electricians (OR = 2.1; 1.1-4.1), performers (OR = 3.2; 1.4-7.4), administrative workers in organizations and enterprises (OR = 1.8; 1.1-2.8), and postal and telecommunication workers (OR = 3.5; 1.6-7.6).

CONCLUSIONS

Our findings suggest that occupational exposures contribute to the development of asthma in women.

A multi-faceted approach to risk assessment of laboratory animal allergens at two facilities

BACKGROUND

Risk assessment of exposure to allergens is difficult because the relationship between exposure, sensitization, and symptoms has not been fully established. Laboratory animal allergens (LAA) are an important occupational health risk factor; 10-32% of workers exposed to these allergens develop allergic diseases. This article introduces a versatile approach to assessing the risks posed by LAA at two laboratory animal facilities.

METHODS

The risk assessment approach that was used at the laboratory animal facilities included questionnaires for management and employees, a hazard identification visit and measurements in the workplaces, as well as the creation of a list of generally recommended procedures to reduce allergen exposure.

RESULTS

The prevalence of work-related allergic symptoms was 17%. Suggested countermeasures at the sites included changes in ventilation and work practices, reduction of unnecessary exposure, recommendations for more comprehensive use of personal protective equipment, and wider communication about LAA risks.

CONCLUSIONS

The approach managed to identify critical points and potential means for controlling LAA exposure.

Prevention of occupational asthma--practical implications for occupational physicians

BACKGROUND

Occupational factors have been estimated to contribute to approximately 10% of adult-onset asthma and occupational asthma (OA) is one of the most common occupational lung diseases in industrialized areas. Persistent asthma frequently occurs with significant socio-economic impacts.

METHODS

A literature search was performed using PubMed. The key term searched was occupational asthma combined with prevention.

RESULTS

Primary prevention has been effective for OA related to natural rubber latex, and may have reduced the incidence of diisocyanate-induced asthma. Medical health surveillance has been effective in settings such as the detergent enzyme industry, workers exposed to complex platinum salts and likely for diisocyanate workers in Ontario. Tertiary prevention is still required for workers with OA and can improve prognosis.

CONCLUSIONS

OA is potentially preventable. Sufficient studies have demonstrated the rationale and benefit of primary preventive strategies. Medical health surveillance programs combined with occupational hygiene measures and worker education have been associated with improved outcomes but further studies are needed to understand the optimum frequency and measures for such programs and to identify the separate contribution of the components. Until primary and secondary prevention is better understood and implemented, there will also remain a need for tertiary preventive measures.

Incidence of allergy and allergy symptoms among workers exposed to laboratory animals

BACKGROUND AND AIMS

Few studies have described relations between exposure to laboratory animals and the incidence of laboratory animal allergy (LAA). Studies that have found exposure-response relations have been cross sectional in design or have focused on exposure to rats and mice. This study used longitudinal data collected over a 12 year period to describe the relations between indices of exposure to laboratory animals and the development of LAA and LAA symptoms.

METHODS

Data were obtained from questionnaires and serological laboratory results from a dynamic cohort of workers exposed to a variety of laboratory animals in a pharmaceutical manufacturing company. Poisson regression was used to model the incidence rate ratios of species specific and general LAA and LAA symptoms at different levels of exposure.

RESULTS

The 12 year incidence rates of LAA symptoms and LAA for all workers were 2.26 (95% CI 1.61 to 2.91) and 1.32 (95% CI 0.76 to 1.87) per 100 person-years, respectively. Higher rate ratios were seen with increasing reported hours of exposure to tasks that required working with animal cages or with many animals at one time. The most common symptoms were related to rhinitis rather than to asthma.

CONCLUSIONS

This study suggests that the risk of LAA increases with duration of exposure to animals and work in animal related tasks. Incidence might be reduced by limiting hours per week of exposure to laboratory animals.

Allergic rhinoconjunctivitis: epidemiology

Allergic rhinoconjunctivitis has been studied much less frequently than asthma using epidemiologic approaches. Population-based studies are difficult to conduct because of misclassification arising from the reliance on self-reported questionnaires that use terms such as allergic rhinitis or hay fever to establish the diagnosis. In addition, many epidemiologic studies focus on diagnostic skin testing or allergen-specific IgE antibodies (RASTs) as an objective outcome to assess for hay fever. These techniques are helpful but not perfect measures for predicting hay fever outcomes in epidemiologic studies. It is generally accepted, however, that allergic rhinoconjunctivitis is one of the most common of chronic diseases and is the most common atopic disorder. This article reviews the definition of allergic rhinoconjunctivitis, the epidemiology of this disorder from infancy into adulthood, and environmental risk factors for development of sensitization to certain allergens.

Laboratory Animal Allergies: Overview of Causation and Prevention

In sensitized individuals, exposure to laboratory animal allergens can cause symptoms ranging in severity from annoying to life-threatening. The author presents an overview of the pathology of LAA and discusses a number of methods that can be used to limit exposure to these allergens.

Chemical safety in animal care, use, and research

Chemical safety is an essential element of an effective occupational health and safety program. Controlling exposures to chemical agents requires a careful process of hazard recognition, risk assessment, development of control measures, communication of the risks and control measures, and training to ensure that the indicated controls will be utilized. Managing chemical safety in animal care and use presents a unique challenge, in part because research is frequently conducted in two very different environments--the research laboratory and the animal care facility. The chemical agents specific to each of these environments are typically well understood by the employees working there; however, the extent of understanding may not be adequate when these individuals, or chemicals, cross over into the other environment. In addition, many chemicals utilized in animal research are not typically used in the research laboratory, and therefore the level of employee knowledge and proficiency may be less compared with more routinely used materials. Finally, the research protocol may involve the exposure of laboratory animals to either toxic chemicals or chemicals with unknown hazards. Such animal protocols require careful review to minimize the potential for unanticipated exposures of the research staff or animal care personnel. Numerous guidelines and regulations are cited, which define the standard of practice for the safe use of chemicals. Key chemical safety issues relevant to personnel involved in the care and use of research animals are discussed.