Symptoms Of Laboratory Animal Allergy Research Articles

LABORATORY ANIMAL ALLERGY (LAA) AMONG THE ANIMAL FACILITIES’ WORKERS IN A RESEARCH INSTITUTE: A CLINICAL SURVEY

Research animal facilities had been identified as a risky environment for the development of Laboratory Animal Allergy (LAA) among the exposed workers. The risk degree is in parallel with the nature of contact, intensity of exposure and individual susceptibility. Early recognition of LAA via active clinical surveillance is imperative before it progresses into occupational asthma with chronic disability. This study aimed to determine the prevalence of LAA among animal facilities’ workers in Institute for Medical Research, Malaysia together with its associated exposure or environmental risk factors. This cross-sectional study recruited a total of 87 workers exposed to animal allergen and 87 control subjects. Self-administered LAA questionnaire contained details of occupational and socio-environmental history as well as lung function test (spirometry) were employed as study tools. Statistical analysis were performed using SPSS version 20, utilizing descriptive analysis , cross tabulation, independent t-test ,Mann Whitney U-test and Multivariable Logistic Regression (MLR).More than half of the exposed subjects were reported at least one LAA symptoms (58.6%) and declined ling function (56.3%). Upper respiratory symptoms were the most prevalent LAA symptoms (49.4%). There was significant association between the reported symptoms and abnormal lung profile (p<0.05). In term of lung function values, the mean FEV1, median FVC and mean FEV1/FVC were significantly lower among the exposed group compared to the control group (p<0.001). MLR substantiated that atopic workers, smokers and those did not comply to full PPE regularly upon animal contact were more likely to develop LAA. LAA is an acknowledged occupational hazard. Therefore knowing the existing prevalence and its risk factors to design an effective LAA prevention program consisted of exposure avoidance as well as exposure reduction which combines the engineering control, administrative control and PPE is of paramount importance.

Laboratory animal allergy is preventable in modern research facilities.

Historical data suggest 15% of laboratory animal workers develop IgE sensitisation and 10% symptoms of laboratory animal allergy (LAA), including occupational asthma. Individually ventilated cages (IVCs) are replacing conventional open cages; we sought to evaluate their impact on the development of LAA. We surveyed 750 laboratory animal workers and measured airborne Mus m 1 (mouse allergen) levels in seven UK institutions. We compared the prevalence of sensitisation to mouse proteins (by specific IgE assay or skin prick test) and of work-related allergic symptoms in IVC-only and open cage units. Full-shift Mus m 1 levels were lower in IVC than open cage units (geometric mean 1.00 (95% CI 0.73-1.36) versus 8.35 (95% CI 6.97-9.95) ng·m-3; p<0.001), but varied eight-fold across the IVC units (geometric mean range 0.33-4.12 ng·m-3). Primary analyses on data from 216 participants with ≤3 years exposure to mice revealed a lower prevalence of sensitisation in those working in IVC units compared with conventional cage units (2.4% (n=2) versus 9.8% (n=13); p=0.052). Sensitisation in IVC units varied from 0% to 12.5%; the use of fitted respiratory protection was less common in IVC units where prevalence of sensitisation was higher. Work-related allergy symptoms were more frequently reported by mouse-sensitised individuals (46.7% versus 10.9%; p<0.001) and only by those working in open cage units. In contemporary practice, LAA is now largely preventable with the use of IVC systems and the judicious use of appropriate respiratory protection.

S6 The Role Of Individually Ventilated Cages In Prevention Of Laboratory Animal Allergy: A Proof Of Concept Study

Introduction and objectives At least 12000 people work with laboratory animals in the UK. Approximately 15% of exposed employees develop specific IgE sensitisation and 10% clinical symptoms of laboratory animal allergy (LAA), a form of occupational asthma. Individually ventilated cages (IVCs) are increasingly replacing conventional open cages (primarily to protect mice from external infection) and whilst this can be associated with lower levels of ambient aeroallergen levels no corresponding reduction in the incidence of LAA is apparent. The SPIRAL (Safe Practice In Reducing Allergy in Laboratories) study is a large multi-centred study designed to increase understanding of the complex association between workplace exposure to mouse allergens and development of sensitisation, and to evaluate the risk of working with mice today. Methods A cross-sectional study of animal workers at seven UK medical research institutions is in progress. We aim to recruit 250 people working in IVC-only facilities and 160 people working in mixed facilities; our primary outcome is a comparison of prevalence of sensitisation to Mus m 1 (mouse urinary antigen) between these two groups. Participants are invited to complete a detailed online questionnaire about work tasks and practices. Skin-prick tests to common aeroallergens and various animal proteins are performed and blood samples analysed for serum specific IgE to Mus m 1. Aeroallergen sampling for particular matter and Mus m 1 is undertaken concurrently to provide additional information about potential exposures. Recently employed individuals are invited to participate in a cohort study to determine incidence rates of laboratory animal allergy. Results 136 individuals have been recruited to date; Table 1 shows their demographics and preliminary immunology results. Prevalence of allergic symptoms and sensitisation is similar to that anticipated. Conclusion The SPIRAL study is the largest, most detailed study of LAA to be carried out. It aims to increase understanding of the relationship between allergen exposure and risk of sensitisation with the goal of significantly reducing the incidence of LAA. The results will be used to develop a “Code of best working practices” for facilities using IVC systems, nationally and further afield.

Characterization of occupational sensitization by multiallergen immunoblotting in workers exposed to laboratory animals

BackgroundStudies have estimated that 10% to 23% of workers exposed to laboratory animals report symptoms of laboratory animal allergy. ObjectivesTo determine the level of occupational sensitization in workers exposed to laboratory animals and to develop a diagnosis system based on a multiallergen IgE immunoblot. MethodsA total of 75 workers exposed to laboratory animals were initially studied with skin prick tests performed with animal epithelia extracts. The workers with suspected occupational disease and positive skin prick test results were further studied with the ImmunoCAP system to determine specific IgE levels to urine and epithelia allergens and with multiallergen IgE immunoblotting to detect specific IgE levels to epithelia allergens and bovine serum albumin. ResultsTwenty of the 75 workers were studied with ImmunoCAP and multiallergen IgE immunoblotting. Nine were polysensitized and 3 were sensitized to only one animal. The results obtained by ImmunoCAP and multiallergen IgE immunoblotting were concordant except for in 3 workers, who had low or negative values of specific IgE determined by ImmunoCAP but positive allergen detections by immunoblotting. On the basis of the results of the study and the clinical symptoms related by workers, 16% were diagnosed as having occupational allergy. ConclusionsMultiallergen immunoblotting by means of a unique test offers a graphic representation of sensitization to the different animals to which workers are exposed, providing additional information on the clinical symptoms caused by the involved allergens. The results presented suggest that this system can improve the diagnosis of laboratory animal allergy by obtaining a sensitization profile for each exposed worker.

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...

Progression of self-reported symptoms in laboratory animal allergy

Laboratory animal allergy is a common illness among workers exposed to laboratory animals and can progress to symptoms of asthma. This study evaluates the continuum of disease from allergy symptoms to asthma symptoms in a dynamic cohort of workers exposed to animals in a pharmaceutical company. Data arose from annual questionnaires administered to workers in a surveillance program established to monitor exposure to animals and the development of allergy. The life-table method was used to compare asthma-free survival between workers with and without symptoms of allergy. A Cox proportional hazards model was used to examine the effects of covariates on the development of asthma. A total of 603 workers contributed 2527.4 person-years to the study over the 12.3-year period. The probabilities of experiencing asthma symptoms by the 11th year of follow-up were 0.367 for workers with allergy symptoms and 0.052 for those without allergy symptoms. The hazard ratio for asthma symptoms when comparing workers with and without allergy symptoms was 7.39 (95% CI, 3.29-16.60) after adjustment for sex and family history of allergy. Female subjects developed asthma at a rate 3.4 times that of male subjects. This study supports the hypothesis that laboratory animal allergy symptoms are a major risk factor for the development of asthma. It also suggests a heightened risk of asthma for women who work with laboratory animals, a finding that has not been previously reported.

Mechanism and epidemiology of laboratory animal allergy.

Laboratory animal allergy (LAA) is a form of occupational allergic disease. The development of laboratory animal allergy is due to the presence of IgE antibodies directed against animal proteins. The process of sensitization (development of IgE antibodies) is a complex process which involves interaction of antigen presenting cells and lymphocytes of the Th-2 cell type. These cells generate a host of cytokines and other factors which lead to immediate hypersensitivity reactions and other factors which lead to immediate hypersensitivity reactions and the generation of allergic inflammation. Typical symptoms of laboratory animal allergy include nasal symptoms, such as sneezing, watery discharge, and congestion. Skin rashes are also common. Asthma, which produces symptoms of cough, wheezing, and shortness of breath, may affect 20-38% of workers who are sensitized to laboratory animal allergens. Rarely a generalized, life-threatening allergic reaction (anaphylaxis) may occur. The estimated prevalence of laboratory animal allergy is variable depending on the method used for diagnosis, but nonetheless may affect up to 46% of exposed workers. The presence of pre-existing allergies to non-work place allergens (e.g., dust mite, pollens, molds), exposure to laboratory animal allergens, and possibly tobacco smoking are risk factors for the development of laboratory animal allergy. Progress in the understanding of the mechanism and epidemiology of laboratory animal allergy will lead to improved methods for its prevention.

Allergen exposure, atopy and smoking as determinants of allergy to rats in a cohort of laboratory employees.

This study aimed to examine the relationship between exposure to rat urinary allergens, atopic status, smoking and the development of allergic symptoms and specific sensitization. It is a case-referent analysis of a cohort of 342 newly employed laboratory animal workers. Cases comprised persons developing symptoms of laboratory animal allergy or a positive skin prick test to rat urinary allergens; each was matched with up to two asymptomatic referents. Subjects were assigned to categories of exposure based on measurements of airborne rat urinary allergens. Of the cases, 80% reported that their symptoms started within 2 yrs of employment. The odds ratio (OR) for development of each symptom type (respiratory, eye or nose and skin) and of an immediate skin test reaction was increased in those with direct contact with rats. A gradient of increasing OR for the development of any such symptom across exposure categories was found; for respiratory symptoms and skin test reactions the OR for subjects in the highest exposure category were lower than those in intermediate categories, a pattern attenuated when the analysis was confined to outcomes developing within 2 yrs of first exposure. Atopy increased the OR of most outcomes as did cigarette smoking, although there was no evidence of a relationship between smoking and the development of a specific skin test reaction. In conclusion, allergen exposure was confirmed as the most important determinant of laboratory animal allergy; by implication, measures to reduce exposure may be the most effective means to reduce its incidence.

Exhaled and nasal nitric oxide is increased in laboratory animal allergy.

Allergens from rats, mice, guinea pigs or rabbits cause up to 30% of exposed persons to develop specific immunoglobulin E (IgE) responses. Laboratory animal allergy (LAA) is among the highest occupational risks for asthma in the UK. Elevated levels of nitric oxide (NO) are found in exhaled breath in asthma. In LAA symptoms may progress from conjunctivitis, rhinitis to asthma. Health surveillance aims to detect early sensitization. To assess whether an association exists between LAA and exhaled NO. A cross-sectional study was performed in 39 laboratory workers undergoing LAA health surveillance. Volunteers completed two health questionnaires, had skin-prick tests, spirometry, total IgE and RAST tests. Exhaled and nasal NO was measured by chemiluminescence analyser (LR2000, Logan Research, Rochester, UK). There were 23 asymptomatic subjects (mean age 29.53 years) and 16 symptomatic subjects (29.63 years, P=0.95); 9 early LAA, seven LAA asthma. Exhaled NO was raised in those with LAA symptoms 17.97 ppb+/-1.24 (mean+/-SEM) compared with asymptomatics 6.08 ppb+/-1.15, P < 0.05. A trend of increased NO by allergic status was observed; asymptomatic, to early LAA, to asthma. One-way analysis of variance compared differences between groups (F ratio 13.93, P < 0.001). Symptomatic subjects also had raised nasal NO, vs asymptomatic subjects (mean difference 378 ppb, P < 0.05). A trend was again observed by allergic status (F ratio 5.28, P=0.01). Raised NO levels in LAA increasing with symptom severity suggest NO may prove a useful additional tool in monitoring for LAA, and possibly the response to exposure reduction or allergy due to other respiratory sensitizers.

Respiratory allergy in laboratory animal workers: a retrospective cohort study using pre-employment screening data.

OBJECTIVES: To study the role of exposure, atopy, and smoking in the development of laboratory animal allergy (LAA) in a retrospective cohort study. METHODS: Between 1977 and 1993, 225 people...

Epidemiologic assessment of laboratory animal allergy among university employees.

The prevalence of, and risk factors for, laboratory animal allergy (LAA) among university employees were evaluated in a cross-sectional university-based study. A stratified random sample was drawn based on current or no laboratory animal exposure and smoking status. Participants received a modified ATS questionnaire; spirometry; methacholine challenge; and intradermal allergen skin tests. One hundred three currently animal-exposed and 113 never-occupationally-exposed employees participated. Controlling for smoking, currently exposed workers were significantly more likely than controls to describe work-related cough, odds ratio (O.R.) = 6.87; wheeze, O.R. = 12.96; and chest tightness, O.R. = 2.89. Skin test reactivity to non-animal antigens was associated in a dose-response fashion with both upper and lower respiratory symptoms, O.R. = 1.45 and 1.65, respectively, for each additional positive skin test. Exposed workers were significantly more likely than controls to react to methacholine at either 10 or 25 mg/ml, while controlling for smoking status, prior allergy, or asthma. Multiple logistic regression analysis revealed history of hay fever, family history of allergy, non-animal skin test positivity, animal bites, age, and smoking status to each be associated with work-related respiratory symptoms. These data suggest that atopy and smoking status are risk factors for LAA symptoms. Smoking was associated with work-related respiratory symptoms among animal-exposed workers, but not with skin test positivity. It is therefore recommended that periodic screening evaluations be performed on laboratory animal workers and that workers who are atopic, are smokers, or are symptomatic be placed in low exposure settings. These data further, support the need for efficient exhaust ventilation, personal protective clothing and, among high risk workers, the use of efficient respiratory protection.

Laboratory animal allergy: a clinical survey of an exposed population.

A clinical survey of workers exposed to laboratory animals in a pharmaceutical company was designed to discover the prevalence and severity of symptoms of laboratory animal allergy (LAA). The overall prevalence of the condition was 30%, and two distinguishable LAA syndromes, termed regional and progressive LAA, were found. The first is characterised by rhinitis with negative skin prick tests. The second consists of rhinitis leading progressively to asthma with positive prick tests. Prick tests were useful diagnostically only in the latter. Atopes were shown not to be at special risk of developing LAA, but if they did so were more likely to progress to asthma. The implications for selection and management policy are outlined and specific measures for the further study of LAA are proposed.