Endotoxin, Ergosterol, Fungal DNA and Allergens in Dust from Schools in Johor Bahru, Malaysia- Associations with Asthma and Respiratory Infections in Pupils

Abstract

There are few studies on associations between respiratory health and allergens, fungal and bacterial compounds in schools in tropical countries. The aim was to study associations between respiratory symptoms in pupils and ethnicity, chemical microbial markers, allergens and fungal DNA in settled dust in schools in Malaysia. Totally 462 pupils (96%) from 8 randomly selected secondary schools in Johor Bahru, Malaysia, participated. Dust was vacuumed from 32 classrooms and analysed for levels of different types of endotoxin as 3-hydroxy fatty acids (3-OH), muramic acid, ergosterol, allergens and five fungal DNA sequences. Multiple logistic regression was applied. Totally 13.1% pupils reported doctor’s diagnosed asthma, 10.3% wheeze and 21.1% pollen or pet allergy. Indian and Chinese children had less atopy and asthma than Malay. Carbon dioxide levels were low (380–690 ppm). No cat (Fel d1), dog (Can f 1) or horse allergens (Ecu cx) were detected. The levels of Bloomia tropicalis (Blo t), house dust mite allergens (Der p 1, Der f 1, Der m 1) and cockroach allergens (Per a 1 and Bla g 1) were low. There were positive associations between levels of Aspergillus versicolor DNA and daytime breathlessness, between C14 3-OH and respiratory infections and between ergosterol and doctors diagnosed asthma. There were negative (protective) associations between levels of C10 3-OH and wheeze, between C16 3-OH and day time and night time breathlessness, between cockroach allergens and doctors diagnosed asthma. Moreover there were negative associations between amount of fine dust, total endotoxin (LPS) and respiratory infections. In conclusion, endotoxin at school seems to be mainly protective for respiratory illness but different types of endotoxin could have different effects. Fungal contamination measured as ergosterol and Aspergillus versicolor DNA can be risk factors for respiratory illness. The ethnical differences for atopy and asthma deserve further attention.

Volatile organic compounds (VOC), formaldehyde and nitrogen dioxide (NO 2 ) in schools in Johor Bahru, Malaysia: Associations with rhinitis, ocular, throat and dermal symptoms, headache and fatigue

“…The participation rate was 96%, a total of 462 pupils participated. All schools had a two shift system, one group was at school from 7 a.m. to 1 p.m. (our study group) and another afternoon shift was at school from 1 p.m.-7 p.m. (not participating in our study).We have previously published results on associations between fungal and bacterial exposure and asthmatic symptoms and airway infections among the students in these schools (Cai et al, 2011;Norbäck et al, 2014;Norbäck et al, 2016).…”

Respiratory symptoms and fractional exhaled nitric oxide (FeNO) among students in Penang, Malaysia in relation to signs of dampness at school and fungal DNA in school dust

“…We used a self-administered questionnaire from previous school studies (Smedje et al, 1997;Cai et al, 2011;Mi et al, 2006;Zhao et al, 2008;Norbäck et al, 2014) with questions on doctors' diagnosed asthma, current asthma, allergies, respiratory symptoms and airway infections obtained from the ISAAC study (Asher et al, 2006), the European Respiratory Health Survey (ECRHS) (Janson et al, 2001) and our previous school studies (Smedje et al, 1997;Cai et al, 2011;Mi et al, 2006;Zhao et al, 2008;Norbäck et al, 2014). There were (yes/ no) questions on doctors' diagnosed asthma, current asthma medication (sprays, tablets etc.)…”

“…Temperature (°C), Relative Humidity (RH, %) and CO 2 (ppm) were measured in the classrooms during normal activities for 1 h with Q-TrakTM monitors (TSI Incorporated, St. Paul, Minnesota, USA). Settled dust was collected from floors, desks and chair (mixed sample) by a 400 W vacuum cleaner provided with a special dust collector (ALK Abello, Copenhagen, Denmark) as in previous school studies (Smedje et al, 1997;Zhao et al, 2008;Norbäck et al, 2014). The dust was sieved through 0.3-mm mesh screen to obtain the fine dust, weighed, and analysed for fungal DNA.…”

“…The method for analysis of fungal DNA has been previously described Norbäck and Cai, 2011;Norbäck et al, 2014). Briefly fungal DNA was extracted from 10 mg of sieved dust and five multiplex reactions were performed in five separate tubes targeting the DNA of the following species: total fungi, Aspergillus spp.…”

The Impact of Microbiological Pollutants on School Indoor Air Quality

“…These were analyzed using quantitative polymerase chain reaction (qPCR) techniques [7]. Allergen levels were determined using two-site sandwich ELISA for house dust mite (Der p1, Der f1), cat (Fel d1), dog (Can f1) while horse allergen (Equ cx) was measured using monoclonal antibodies [8] [9]. Due to the lack of established guidelines, data has been reported in quartiles and schools having indoor concentrations within the upper quartile were considered as having elevated levels of the particular microbiological or allergen contaminant.…”