Progression of self-reported symptoms in laboratory animal allergy

Comparison of high- and low-molecular-weight sensitizing agents causing occupational asthma: an evidence-based insight

INTRODUCTION

The many substances used at the workplace that can cause sensitizer-induced occupational asthma are conventionally categorized into high-molecular-weight (HMW) agents and low-molecular-weight (LMW) agents, implying implicitly that these two categories of agents are associated with distinct phenotypic profiles and pathophysiological mechanisms.

AREAS COVERED

The authors conducted an evidence-based review of available data in order to identify the similarities and differences between HMW and LMW sensitizing agents.

EXPERT OPINION

Compared with LMW agents, HMW agents are associated with a few distinct clinical features (i.e. concomitant work-related rhinitis, incidence of immediate asthmatic reactions and increase in fractional exhaled nitric oxide upon exposure) and risk factors (i.e. atopy and smoking). However, some LMW agents may exhibit 'HMW-like' phenotypic characteristics, indicating that LMW agents are a heterogeneous group of agents and that pooling them into a single group may be misleading. Regardless of the presence of detectable specific IgE antibodies, both HMW and LMW agents are associated with a mixed Th1/Th2 immune response and a predominantly eosinophilic pattern of airway inflammation. Large-scale multicenter studies are needed that use objective diagnostic criteria and assessment of airway inflammatory biomarkers to identify the pathobiological pathways involved in OA caused by the various non-protein agents.

Occupational Rhinitis

There is convincing evidence that tight relationships between the upper and lower airways also apply to the workplace context. Most patients with occupational asthma (OA) also suffer from occupational rhinitis (OR), although OR is 2 to 3 times more common than OA. OR most often precedes the development of OA, especially when high-molecular-weight protein agents are involved, and longitudinal cohort studies have confirmed that OR is associated with an increased risk for the development of OA. The level of exposure to sensitizing agents at the workplace is the most important determinant for the development of IgE-mediated sensitization and OR. Atopy is a risk factor for the development of IgE-mediated sensitization only to high-molecular-weight agents. In workers with work-related rhinitis symptoms, documentation of IgE-mediated sensitization to a workplace agent via skin prick testing or serum specific IgE confirms a diagnosis of probable OR, whereas specific nasal provocation testing in the laboratory remains the reference method to establish a definite diagnosis of OR. Complete avoidance of exposure to the causal agent is the most effective therapeutic option for controlling work-related nasal symptoms and preventing the development of OA. If complete elimination of exposure is expected to induce meaningful adverse socioeconomic consequences, reduction of exposure can be considered as an alternative approach, but it is important to consider the individual risk factors for the development of OA to implement a more personalized management of OR.

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.

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.

[Occupational asthma: Clinical and professional profile of the Tunisian asthmatic worker]

INTRODUCTION

Asthma takes up a great importance in occupational diseases but remains underestimated as it is insufficiently diagnosed.

OBJECTIVE

We aimed to access the clinical and professional profile of the Tunisian asthmatic worker.

MATERIALS AND METHODS

It was a retrospective descriptive study in a professional pathology unit in a university hospital. All patients referred by their doctor for symptoms suggestive of occupational asthma, during a period from 2000 to 2008, were included.

RESULTS

Forty-eight patients were selected from 172. The mean age was 40 years, with a male predominance (56 %). In 2/3 of the cases, it was the textile workers, food and chemical industry. The etiological agents incriminated were textile dust in 18.8 % of cases followed by isocyanates and flour. Typical episodes of wheezing dyspnea were present in 52 % and atopy in 54.2 % of workers. In 2 % of cases, symptoms disappeared and worsened in 18.8 %.

CONCLUSIONS

The prognosis of OA depends on early end accurate diagnosis. The physician's role is to initiate the appropriate diagnostic approach, which must comply with the Tunisian conditions.

When to suspect occupational asthma

Occupational asthma (OA) is a difficult diagnosis to make. The present review describes the work environments in which workers are at risk for developing OA, the characteristics of the individuals in whom OA should be suspected and the investigation that can be performed to diagnose the condition. Accurately diagnosing OA is crucial because of the major social and economic consequences of this diagnosis on the patient.

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.

Medical surveillance for prevention of occupational asthma

PURPOSE OF REVIEW

Because there is sufficient knowledge of its environmental determinants, occupational asthma is a disease that ought to be largely preventable; yet its incidence in many settings remains unacceptably high. Here we review one approach to prevention: the routine use of health surveillance in exposed workforces.

RECENT FINDINGS

Health surveillance is widely practised but there is little evidence that it is used strategically to reduce disease incidence. There are several barriers to the effective use of its various components, chiefly symptoms questionnaires and spirometry. Cost-benefit analyses may help to increase the uptake of industry-wide workplace interventions.

SUMMARY

The effective use of health surveillance for occupational asthma continues to be challenging and there remains relatively little published evidence that will encourage those involved to use it more efficiently. Useful advances could be made by greater collaboration between employers, employee organizations, legislators and researchers.

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: etiologies and risk factors

The purpose of this article is to critically review the available evidence pertaining to occupational, environmental, and individual factors that can affect the development of occupational asthma (OA). Increasing evidence suggests that exploration of the intrinsic characteristics of OA-causing agents and associated structure-activity relationships offers promising avenues for quantifying the sensitizing potential of agents that are introduced in the workplace. The intensity of exposure to sensitizing agents has been identified as the most important environmental risk factor for OA and should remain the cornerstone for primary prevention strategies. The role of other environmental co-factors (e.g., non-respiratory routes of exposure and concomitant exposure to cigarette smoke and other pollutants) remains to be further delineated. There is convincing evidence that atopy is an important individual risk factor for OA induced by high-molecular-weight agents. There is some evidence that genetic factors, such as leukocyte antigen class II alleles, are associated with an increased risk of OA; however, the role of genetic susceptibility factors is likely to be obscured by complex gene-environment interactions. OA, as well as asthma in general, is a complex disease that results from multiple interactions between environmental factors and host susceptibilities. Determining these interactions is a crucial step towards implementing optimal prevention policies.

Asthma and rhinitis in the workplace

Accumulating evidence indicates that the workplace environment substantially contributes to the global burden of asthma and rhinitis. Work-related asthma and rhinitis represent a public health concern due to their health and socioeconomic impacts. This article summarizes the scientific evidence on sensitizer-induced occupational asthma and rhinitis that has been published during the past 5 years. The review addresses the strategies for diagnosing and managing these highly prevalent occupational diseases.

EAACI position paper on occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and non-European countries on Occupational Rhinitis (OR), a disease of emerging relevance which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored on that of occupational asthma, as well as a diagnostic algorithm based on steps allowing for different levels of diagnostic evidence are proposed. The needs for future research are pointed out. Key messages are issued for each item.

Occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and nonEuropean countries on Occupational Rhinitis (OR), a disease of emerging relevance, which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored to that of occupational asthma, as well as a diagnostic algorithm based on steps allowing different levels of diagnostic evidence, are proposed. The needs for future research are pointed out. Key messages are issued for each item.

[Epidemiology and etiologic agents of occupational asthma]

INTRODUCTION

Occupational asthma is, by definition, a disease that can be prevented through appropriate protective strategies. Epidemiological information is required to guide these interventions, and we here examine epidemiological data on the burden, causes, and risk factors for this condition.

STATE OF THE ART

Population-based surveys indicate that approximately 15% of adult asthma is attributable to the workplace environment. The most common occupational agents implicated include flour, isocyanates, latex, and persulphate salts. The occupations in which occupational asthma has been most commonly reported are bakers, spray painters, health-care workers, hairdressers, and cleaners. The level of exposure to sensitizing agents seems to be the most relevant risk factor. Atopy is a significant risk factor only for the development of sensitization to high molecular weight agents. The role of other individual determinants, such as genetic factors, has been less consistently established. Occupational asthma is associated with a substantial adverse impact on the employment and financial status of affected workers.

PERSPECTIVES

Methodological improvements are required in order to distinguish more accurately between occupational and work-exacerbated asthma. Further investigations of the effectiveness of primary and secondary preventive interventions are also needed.

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.

New insights into laboratory animal exposures and allergic responses

PURPOSE OF REVIEW

To update the epidemiology of laboratory animal allergy, identify new exposures in the laboratory animal workplace, discuss complexities in the exposure-response relationship, and review the immunology of symptomatic and allergic responses.

RECENT FINDINGS

Laboratory animal allergy remains a common occupational hazard of research scientists, technicians and animal handlers. The epidemiology is typical of a stable workforce: incidence is low, although prevalence is high. Risk factors of atopy, current exposures, and sensitization to cats or dogs incompletely predict disease. Exposures include a complex, potent mixture of allergens, biological adjuvants such as endotoxin and irritants. The dose-response relationship between laboratory animal exposure, sensitization and symptoms is hard to define: cross-sectional studies identify most sensitized workers in moderate laboratory animal exposure, not in the highest exposure. Exposure assessments based on workday averages underestimate exposure peaks that may be significant for symptoms and disease. Although we have assumed that workers without symptoms are not sensitized to laboratory animal allergens, recent data demonstrate that many asymptomatic workers do make laboratory animal-specific immune responses that may be necessary to prevent symptomatic disease.

SUMMARY

Understanding laboratory animal exposures and disease must include exposures other than allergen, and responses other than allergic disease.

Prevalence and host determinants of occupational bronchial asthma in animal shelter workers

OBJECTIVE

We examined the risk factors for the development of airway allergy in animal shelter workers.

METHODS

The study population comprised 88 animal shelter workers occupationally exposed to cats and dogs. They responded to a questionnaire concerning the history of exposure to animal allergens and job characteristics and were subjected to skin prick test (SPT) to common and occupational allergens (cat and dog), and determination of total serum IgE level and specific IgE. In addition, SPT with rat and mouse allergens were performed. Bronchial hyperreactivity and peak expiratory flow rate were measured at work and off work only in workers with work-related symptoms suggestive of occupational asthma (OA).

RESULTS

The prevalence of OA was 9.1%. Sensitization to dog allergens was higher than to cats. The multivariate logistic regression analysis revealed a significant role of positive family history of atopy and having a dog as pet in the past for the development of occupational airway allergy (OR 5.9; 95% CI 1.76, 20.00; P = 0.003; OR 6.47; 95% CI 1.90, 22.02; P = 0.002, respectively). In the multivariate logistic regression analysis, the risk for developing OA was most clearly associated with growing up in the country (OR 7.59; 95% CI 1.25, 45.9; P = 0.025).

CONCLUSIONS

Allergic disease is a serious occupational health concern for subjects who have occupational contact with cats and dogs.

Risk factors associated with airway allergic diseases from exposure to laboratory animal allergens among veterinarians

OBJECTIVES

Investigate the risk factors for the development of occupational airway allergy (OAA) from exposure to laboratory animal allergens (LAA) among Polish veterinarians.

METHODS

Two hundred veterinarians responded to the questionnaire and were subjected to skin prick test (SPT) to common allergens and LAA (rat, mouse, hamster, guinea pig, rabbit). Evaluation of total serum IgE level and specific IgE against occupational allergens was performed. In addition, bronchial hyperreactivity (BHR) and peak expiratory flow rate (PEFR) were measured before and after specific challenge testing (SCT) only in the subjects with work-related symptoms suggestive of occupational asthma (OA).

RESULTS

The prevalence of asthmatic and ocular symptoms was statistically more prevalent in the group of veterinarians sensitised to LAA versus non-sensitised subjects. The most frequent occupational allergens of skin and serum reactivity were LAA (44.5 and 31.5%, respectively). In 41 (20.5%) and in 22 (11%) subjects out of 200 veterinarians, serum specific IgE to natural rubber latex (NRL) allergens and disinfectants was also found. Serum sensitisation to cat allergens and daily contact with laboratory animals (LA) increased the risk for developing isolated occupational rhinitis. Furthermore, working time of more than 10 years and daily contact with LA were also significant risk factors for the development of OAA. Measuring PEFR and BHR before and after SCT is a useful method to confirm the presence of OA.

CONCLUSIONS

Allergy to LAA is an important health problem among veterinary medicine practitioners in Poland.

A brief targeted review of susceptibility factors, environmental exposures, asthma incidence, and recommendations for future asthma incidence research

Relative to research on effects of environmental exposures on exacerbation of existing asthma, little research on incident asthma and environmental exposures has been conducted. However, this research is needed to better devise strategies for the prevention of asthma. The U.S. Environmental Protection Agency (EPA) and National Institute of Environmental Health Sciences held a conference in October 2004 to collaboratively discuss a future research agenda in this area. The first three articles in this mini-monograph summarize the discussion on potential putative environmental exposure; they include an overview of asthma and conclusions of the workshop participants with respect to public health actions that could currently be applied to the problem and research needs to better understand and control the induction and incidence of asthma, the potential role of indoor/outdoor air pollutants in the induction of asthma), and biologics in the induction of asthma. Susceptibility is a key concept in the U.S. EPA "Asthma Research Strategy" document and is associated with the U.S. EPA framework of protecting vulnerable populations from potentially harmful environmental exposures. Genetics, age, and lifestyle (obesity, diet) are major susceptibility factors in the induction of asthma and can interact with environmental exposures either synergistically or antagonistically. Therefore, in this fourth and last article we consider a number of "susceptibility factors" that potentially influence the asthmatic response to environmental exposures and propose a framework for developing research hypotheses regarding the effects of environmental exposures on asthma incidence and induction.