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Fungal DNA, Mould, Dampness and Allergens in Schools and Day Care Centers and Respiratory Health
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Day care centers and schools are important environments for children, but few epidemiological studies exist from these environments. Mould, dampness, fungal DNA and allergens levels in these environments and respiratory health effects in school children were investigated in this thesis. In the day care centers studies, Allergen Avoidance Day care Centers (AADCs) and Ordinary Day care Centers were included. One third of the Swedish day care centers had a history of dampness or mould growth. Total fungal DNA levels were positively associated with risk construction buildings, reported dampness/moulds, rotating heat exchangers, linoleum floors and allergens (cat, dog, horse allergen) levels. The two school studies included secondary schools in Johor Bahru, Malaysia and elementary schools from five European countries (Italy, Denmark, Sweden, Norway, and France) (HESE-study). In Malaysia, 13 % of the pupils reported doctor-diagnosed asthma but only 4 % had asthma medication. The prevalence of wheeze in the last 12 months was 10 % in Malaysia and 13 % in the HESE-study. Cough and rhinitis were common among children in the HESE-study. There were associations between fungal DNA and reported dampness or mould growth. Fungal DNA levels and viable mould (VM) concentration in the classrooms were associated with respiratory symptoms (wheeze, rhinitis, cough, daytime breathlessness) in school children. In the HESE-study, associations were found between total fungal DNA, Aspergillus/Penicillium DNA and respiratory symptoms among children. Moreover, Aspergillus versicolor DNA and Streptomyces DNA were associated with respiratory symptoms in Malaysia and the HESE-study, as well as reduced lung function [forced vitality capacity (FVC) and forced expiratory volume in 1 second (FEV1)] among children in the HESE-study. In conclusion, fungal DNA and pet allergens were common in day care centers and schools and respiratory symptoms in school children were common. The associations between VM concentration and fungal DNA levels in the schools and respiratory health effects in school children indicated a need for improvement of these environments. Moreover, risk constructions should be avoided and buildings should be maintained to avoid dampness and microbial growth. Health relevance of microbial exposure and biodiversity needs to be further studied using molecular methods.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. , 85 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 942
Keyword [en]
Day care centers, Quantitative PCR, Fungal DNA, Allergens, Indoor environment, Building dampness, Bacteria, Mycotoxins, Respiratory symptoms, Asthma, School environment, Viable moulds, School children
National Category
Clinical Medicine
Research subject
Occupational and Environmental Medicine
Identifiers
URN: urn:nbn:se:uu:diva-209597ISBN: 978-91-554-8788-1 (print)OAI: oai:DiVA.org:uu-209597DiVA: diva2:658668
Public defence
2013-12-06, Frödingsalen, Ulleråkersvägen 40, Uppsala, 13:00 (English)
Opponent
Supervisors
Available from: 2013-11-15 Created: 2013-10-22 Last updated: 2014-01-23
List of papers
1. Quantitative PCR analysis of fungal DNA in Swedish day care centers and comparison with building characteristics and allergen levels
Open this publication in new window or tab >>Quantitative PCR analysis of fungal DNA in Swedish day care centers and comparison with building characteristics and allergen levels
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2009 (English)In: Indoor Air, ISSN 0905-6947, E-ISSN 1600-0668, Vol. 19, no 5, 392-400 p.Article in journal (Refereed) Published
Abstract [en]

 Sweden has had allergen-avoidance day care centers (AADCs) since 1979. The aim of this study was to measure fungal DNA by quantitative polymerase chain reaction (qPCR), a new method, in AADCs and ordinary day care centers (ODCs) and examine associations between allergen levels and building characteristics. Dust samples were collected by swabbing doorframes, vacuum-cleaning, and using Petri dishes. In total, 11 AADCs and 11 ODCs were studied (70 rooms). Total fungal DNA, measured by qPCR in the swab dust, was detected in 89%, Aspergillus or Penicillium (Asp/Pen) DNA in 34%, and Stachybotrys chartarum DNA in 6% of the rooms. Total fungal DNA was significantly higher in rooms with linoleum floor (P = 0.02), textile carpets (P = 0.03), reported dampness/molds (P = 0.02) and reported odor (P < 0.001) in the buildings, and significantly lower in wooden facade buildings (P = 0.003). Reported odor was related to the amount of sieved fine dust, reported dampness/molds and type of building construction. Total fungal DNA was related to cat, dog, horse and total allergen levels (P = 0.003) in the day care centers. In conclusion, total fungal DNA is related to reported dampness/molds, reported odor, and type of wall construction. The association between fungal and allergen contamination indicated a general 'hygiene factor' related to biological contaminants. Practical Implications The associations between fungal DNA, reported dampness/molds, and odor support the view that buildings with odor problems should be investigated for possible hidden fungal growth. There is a need to measure fungal biomass in different types of building constructions by monitoring fungal DNA. Analysis of fungal DNA with quantitative PCR can be a fast and practical way to study indoor fungal contamination. Swabbing dust from the doorframe of the main entrance to the room can be a convenient method of sampling dust for fungal DNA analysis. The high prevalence of reported dampness/molds and the common occurrence of fungal DNA indicate the need to improve the indoor environment of Swedish day care centers.

Keyword
Day care centers, Quantitative PCR, Fungal DNA, Allergen levels, Indoor environment, Building dampness
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-122932 (URN)10.1111/j.1600-0668.2009.00600.x (DOI)000269874800003 ()19500176 (PubMedID)
Available from: 2010-04-21 Created: 2010-04-21 Last updated: 2017-12-12Bibliographically approved
2. Fungal DNA and pet allergen levels in Swedish day care centers and associations with building characteristics
Open this publication in new window or tab >>Fungal DNA and pet allergen levels in Swedish day care centers and associations with building characteristics
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2011 (English)In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 13, no 7, 2018-2024 p.Article in journal (Refereed) Published
Abstract [en]

Pet allergens and mold growth related to damp are common phenomena in day care centers in Sweden but exposure measurements of these factors are lacking. The aim of this study was to investigate the relationship between building construction and indoor environment quality in Swedish day care centers and the potential for exposure to fungi (analyzed by quantitative PCR) and animal allergens (analyzed by ELISA). Measurements were performed in 21 day care centers (103 rooms) from one municipality in Sweden, which were identified as constructions at risk of dampness (85% of the buildings) and with visible damage and mold growth (54% of the buildings). Dust samples were collected using cotton swab and Petri dishes. Total fungal DNA was detected in 99% and 100%, Aspergillus/Penicillium DNA in 54% and 68%, and Stachybotrys chartarum DNA in 4% and 9% of the investigated rooms in cotton swab and Petri dish samples, respectively. The total fungal DNA levels (Geometric Mean, GM) were 4.2 × 106 cell equivalents per m2 and 2.9 × 105 cell equivalents per m2 per day in the swab and Petri dish samples, respectively. The concentrations (GM) of cat (Fel d1), dog (Can f1), and horse (Equ cx) allergens were 9.4, 7.2 ng m−2 day−1, and 5.0 unit per m2 per day, respectively. Total fungal DNA levels were higher in risk construction buildings (p = 0.01), in rooms with linoleum flooring material (p = 0.003), and in buildings with rotating heat exchangers (p = 0.02). There were associations between total fungal DNA levels and cat (p = 0.02), dog (p < 0.001), and horse (p = 0.001) allergens. In conclusion, risk constructions, damp constructions, mould growth, fungal DNA, and animal allergens were common exposure factors in Swedish day care centers. Building constructions that represent a high risk for internal dampness should be avoided in the future, and measures to reduce allergen levels should be considered to protect pet-allergic children from asthmatic problems.

National Category
Environmental Health and Occupational Health
Identifiers
urn:nbn:se:uu:diva-165162 (URN)10.1039/c0em00553c (DOI)000292984100018 ()21637862 (PubMedID)
Available from: 2012-01-03 Created: 2012-01-03 Last updated: 2017-12-08Bibliographically approved
3. Fungal DNA, allergens, mycotoxins and associations with asthmatic symptoms among pupils in schools from Johor Bahru, Malaysia
Open this publication in new window or tab >>Fungal DNA, allergens, mycotoxins and associations with asthmatic symptoms among pupils in schools from Johor Bahru, Malaysia
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2011 (English)In: Pediatric Allergy and Immunology, ISSN 0905-6157, E-ISSN 1399-3038, Vol. 22, no 3, 290-297 p.Article in journal (Refereed) Published
Abstract [en]

P>While there is a large variation of prevalence of asthma symptoms worldwide, what we do know is that it is on the rise in developing countries. However, there are few studies on allergens, moulds and mycotoxin exposure in schools in tropical countries. The aims were to measure selected fungal DNA, furry pet allergens and mycotoxins in dust samples from schools in Malaysia and to study associations with pupils' respiratory health effects. Eight secondary schools and 32 classrooms in Johor Bahru, Malaysia were randomly selected. A questionnaire with standardized questions was used for health assessment in 15 randomly selected pupils from each class. The school buildings were inspected and both indoor and outdoor climate were measured. Dust samples were collected by cotton swabs and Petri dishes for fungal DNA, mycotoxins and allergens analysis. The participation rate was 96% (462/480 invited pupils), with a mean age of 14 yr (range 14-16). The pupils mostly reported daytime breathlessness (41%), parental asthma or allergy (22%), pollen or pet allergy (21%) and doctor-diagnosed asthma (13%) but rarely reported night-time breathlessness (7%), asthma in the last 12 months (3%), medication for asthma (4%) or smoking (5%). The inspection showed that no school had any mechanical ventilation system, but all classrooms had openable windows that were kept open during lectures. The mean building age was 16 yr (range 3-40) and the mean indoor and outdoor CO2 levels were 492 ppm and 408 ppm, respectively. The mean values of indoor and outdoor temperature and relative humidity were the same, 29 degrees C and 70% respectively. In cotton swab dust samples, the Geometric Mean (GM) value for total fungal DNA and Aspergillus/Penicillium (Asp/Pen) DNA in swab samples (Cell Equivalents (CE)/m2) was 5.7*108 and 0.5*108, respectively. The arithmetic mean (CE/m2) for Aspergillus versicolor DNA was 8780, Stachybotrys chartarum DNA was 26 and Streptomyces DNA was 893. The arithmetic means (pg/m2) for the mycotoxins sterigmatocystin and verrucarol were 2547 and 17, respectively. In Petri dish dust samples, the GM value for total fungal DNA and Asp/Pen DNA (CE/m2 per day) was 9.2*106 and 1.6*106, respectively. The arithmetic mean (CE/m2 per day) for A. versicolor DNA was 1478, S. chartarum DNA was 105 and Streptomyces DNA was 1271, respectively. The GM value for cat (Fel d1) allergen was 5.9 ng/m2 per day. There were positive associations between A. versicolor DNA, wheeze and daytime breathlessness and between Streptomyces DNA and doctor-diagnosed asthma. However, the associations were inverse between S. chartarum DNA and daytime breathlessness and between verrucarol and daytime breathlessness. In conclusion, fungal DNA and cat allergen contamination were common in schools from Malaysia and there was a high prevalence of respiratory symptoms among pupils. Moreover, there were associations between levels of some fungal DNA and reported respiratory health in the pupils.

Keyword
allergens, fungal DNA, quantitative PCR, bacteria, mycotoxins, respiratory symptoms, asthma, school environments, indoor environments
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-151961 (URN)10.1111/j.1399-3038.2010.01127.x (DOI)000289159800006 ()21457336 (PubMedID)
Available from: 2011-04-29 Created: 2011-04-20 Last updated: 2017-12-11Bibliographically approved
4. Total viable molds and fungal DNA in classrooms and association with respiratory health and pulmonary function of European schoolchildren
Open this publication in new window or tab >>Total viable molds and fungal DNA in classrooms and association with respiratory health and pulmonary function of European schoolchildren
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2011 (English)In: Pediatric Allergy and Immunology, ISSN 0905-6157, E-ISSN 1399-3038, Vol. 22, no 8, 843-852 p.Article in journal (Refereed) Published
Abstract [en]

Indoor molds are associated with adverse respiratory effects in children. Although schools are important exposure sources of molds, objective measurements were more often taken in homes. Our aim was to assess indoor molds in schools and related effects on schoolchildren health. The Health Effects of the School Environment study (HESE) included 21 schools (46 classrooms) in Italy, Denmark, Sweden, Norway, and France and 654 schoolchildren (mean age 10 yr). Information on schoolchildren was collected by standardized questionnaires. Measurements of total viable molds (VM, colony-forming units, cfu/m(3) ) and total/specific fungal DNA (cell equivalents, CE/g dust) were taken inside all classrooms in the cold season during normal activities, using the same standardized methodology. Pulmonary function tests were performed on 244 pupils. VM (mean, 320 cfu/m(3) ) and total fungal DNA (geometric mean, 2.2 × 10(5)  ± 2.1 CE/g dust) were detectable in all classrooms. The levels were significantly higher in buildings with mold/dampness problems. VM, but not fungal DNA, were inversely related to ventilation rate. VM exceeded the maximum standard of 300 cfu/m(3) in 33% of the classrooms. In the past 12 months, dry cough at night (34%) and rhinitis (32%) were the mostly reported. Children exposed to VM levels ≥300 cfu/m(3) , compared with those exposed to lower levels, showed higher risk for past year dry cough at night (odds ratio, OR: 3.10, 95% confidence interval, CI: 1.61-5.98) and rhinitis (OR: 2.86, 95% CI: 1.65-4.95), as well as for persistent cough (OR: 3.79, 95% CI: 2.40-5.60). Aspergillus/Penicillium DNA was significantly positively associated with wheeze, and Aspergillus versicolor DNA with wheeze, rhinitis, and cough. There were significant inverse associations of Aspergillus versicolor DNA with forced vitality capacity (FVC) and Streptomyces DNA with both FEV(1) and FVC. In conclusion, indoor VM and fungal DNA were commonly found in monitored European schools and adversely related to respiratory health. Schools should be routinely tested through both culturable and non-culturable methods for global indoor molds' evaluation.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-165153 (URN)10.1111/j.1399-3038.2011.01208.x (DOI)000298095300013 ()22122789 (PubMedID)
Available from: 2012-01-03 Created: 2012-01-03 Last updated: 2017-12-08Bibliographically approved

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