Exposure to indoor allergens in day-care facilities: Results from 2 North Carolina counties
Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, MD, USA. Journal of Allergy and Clinical Immunology
(Impact Factor: 11.48).
08/2005; 116(1):133-9. DOI: 10.1016/j.jaci.2005.04.022
With 63% of US children under 5 years of age in regular child care, day-care facilities could be an important source of exposure to indoor allergens.
This study examined levels of 7 indoor allergens in 89 day-care facilities in 2 North Carolina counties.
At each facility, a questionnaire was administered, observations were made, and vacuumed dust samples were collected from carpeted and noncarpeted areas of one room. Allergen concentrations were measured with antibody-based ELISAs.
Each allergen was detected in a majority of facilities (52% to 100%). Geometric mean concentrations were 5.19 mug/g for Alternaria alternata , 2.06 mug/g for Can f 1, 1.43 microg/g for Fel d 1, 0.21 U/g for Bla g 1, 0.20 microg/g for Der p 1, 0.10 microg/g for Der f 1, and 0.01 microg/g for Mus m 1. Concentrations for 5 of the 7 allergens were not statistically different from concentrations found in southern US homes sampled in the National Survey of Lead and Allergens in Housing. In rooms with carpet and hard-surfaced flooring, levels of A alternata , Can f 1, Der f 1, Der p 1, and Fel d 1 were statistically higher on carpet.
In this survey of day-care facilities in North Carolina, detectable levels of indoor allergens were commonly found. For many young children and day-care staff, day-care facilities might be a source of clinically relevant exposures to indoor allergens.
Available from: Sabina Wünschmann
- "Exposure to high levels of Alternaria spores in the US Midwest during the spring and summer months is a risk factor for asthma attacks and has been associated with respiratory arrest among children and young adults (1) . Sensitization and exposure to Alternaria species was also associated with asthma in the Inner City Asthma Studies and the most recent National Health and Nutrition Examination Survey (2) (3) (4) (5) (6) . "
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ABSTRACT: Focus on…Alt a 1 Exposure to high levels of Alternaria spores in the US Midwest during the spring and summer months is a risk factor for asthma attacks and has been associated with respiratory arrest among children and young adults (1) . Sensitization and exposure to Alternaria species was also associated with asthma in the Inner City Asthma Studies and the most recent National Health and Nutrition Examination Survey (2-6) . Most research has focused on A. alternata. Thirteen allergens of Alternaria alternata have been identified, however only Alt a 1 is considered a major allergen. Alt a 1 is a dimer of 29 kDa that dissociates into 14.5 and 16 kDa subunits under reducing conditions and is recognized by approximately 80% of Alternaria-allergic patients (7) . Alt a 1 has been cloned and the recombinant allergen has been used to measure IgE and IgG antibody responses in patients with Alternaria allergy. Recombinant Alt a 1 induces skin prick reactivity comparable with natural Alt a 1 or A. alternata extract and is sufficient for a reliable diagnosis of A. alternata sensitization (7-9) . Homologs of Alt a 1 have been identified as allergens primarily in other Alternaria species (10) . The three-dimensional structure of the E. coli expressed recombinant Alt a 1 has just recently been solved through collaborative NIH supported research studies between scientists at INDOOR Biotechnologies and crystallographers and structural biologists at the University of Virginia. Chruszcz et al published the crystal structure of Alt a 1, determined by means of x-ray crystallography in the JACI (11) . The study reveals that Alt a 1 has a unique β-barrel structure, comprised of 11 β-strands, which form a "butterfly-like" dimer that is linked by a single disulfide bond (Figure 1). Dimerization of Alt a 1 provides an explanation for the ability to use the same monoclonal antibody for capture and detection of the allergen in a sandwich ELISA. INDOOR Biotechnologies recently expressed rAlt a 1 in Pichia pastoris (rAlt a 1-P). rAlt a 1-P was purified and compared to the E. coli expressed rAlt a 1 (rAlt a 1-E) by SDS-PAGE, mAb ELISA and IgE Ab ELISA. Under non-reducing conditions SDS-PAGE shows the rAlt a 1-P dimer at ~29kD (Fig. 2A, Lane 2) and the rAlt a 1-E dimer and monomer at ~29kD and ~15kD, respectively (Lane 3). Under reducing conditions only the rAlt a 1 monomer is visible (inset). Immunoreactivity of rAlt a 1 was measured using a mAb ELISA and by chimeric ELISA assay for IgE. No difference in mAb binding was seen between rAlt a 1 constructs (Fig.2B), and IgE binding of rAlt a 1-P showed an excellent correlation to that of rAlt a 1-E (Fig. 3).
Available from: Coby Schal
- "of their time , often in close contact with settled dust on carpeted ßoors . The Bla g 1 aeroallergen concentrations we mea - sured in conventionally treated schools were similar to measurements that we have made in North Carolina homes ( Arbes et al . 2003 , 2004 ; Sever et al . 2007 ) and to levels measured in North Carolina daycare facilities ( Arbes et al . 2005b ) . It is important to recognize that , although children may encounter cockroach and other allergens in various settings , they spend most of their time in the school and home environments , where sensitization and exposure risks are highest . It is not surprising , therefore , that a positive corre - lation was found between asthma pr"
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ABSTRACT: Cockroach suppression is fundamental to cockroach allergen mitigation in infested homes. The effects of various cockroach control strategies on cockroach populations and allergen concentration have not been examined in schools. This study was conducted to compare the effectiveness of integrated pest management (IPM) and conventional pest control in controlling German cockroach (Blattella germanica L.) infestations and concentrations of the cockroach allergen Bla g 1 in public school buildings. Two school districts included six schools that used conventional pest control and one district included seven schools that used IPM to control pests. Cockroach traps were deployed to assess the level of infestation, settled dust samples were collected in food service areas, classrooms, and other school areas, and the Bla g 1 allergen was quantified by ELISA. Both cockroach counts and Bla g 1 concentrations were dependent on the pest control approach, with highly significant differences between IPM-treated schools and conventionally treated schools in both the cockroach mean trap counts (0 versus 82.6 +/- 17.3 cockroaches/trap/wk, respectively) and in the amount of Bla g 1 in dust samples (2.8 +/- 0.3 versus 30.6 +/- 3.4 U/g dust). Cockroaches and Bla g 1 were primarily associated with food preparation and food service areas and much less with classrooms and offices. Our data extend recent findings from studies in homes, showing that cockroach allergens can be reduced by cockroach elimination alone or by integrating several tactics including education, cleaning, and pest control. IPM is not only effective at controlling cockroaches but also can lead to long-term reductions in cockroach allergen concentrations, resulting in a healthier environment for students and school personnel.
Available from: Richard D Cohn
- "The estimated prevalence of detectable Bla g 1 concentrations in 63% of homes is consistent with other research that found 52% prevalence in a regional sample of child care facilities (Arbes et al. 2005b). "
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ABSTRACT: We characterized the prevalence of cockroach allergen exposure in a nationally representative sample of U.S. homes and assessed risk factors for elevated concentrations.
We used data from the National Survey of Lead and Allergens in Housing, a population-based cross-sectional survey.
Participants were residents of 831 U.S. homes in the survey. EVALUATIONS/MEASUREMENTS: We analyzed allergen, questionnaire, and observational data of 831 U.S. homes.
Cockroach allergen (Bla g 1) concentrations exceed 2.0 U/g, a level associated with allergic sensitization, in 11% of U.S. living room floors and 13% of kitchen floors. Concentrations exceed 8.0 U/g, a level associated with asthma morbidity, in 3% of living room floors and 10% of kitchen floors. Elevated concentrations were observed in high-rise apartments, urban settings, pre-1940 constructions, and households with incomes < $20,000. Odds of having concentrations > 8.0 U/g were greatest when roach problems were reported or observed and increased with the number of cockroaches observed and with indications of recent cockroach activity.
Household cockroach allergen exposure is characterized in a nationally representative context. The allergen is prevalent in many settings, at levels that may contribute to allergic sensitization and asthma morbidity.
Likelihood of exposure can be assessed by consideration of demographic and household determinants.
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