Fungal DNA in dust in Swedish day care centres: associations with respiratory symptoms, fractional exhaled nitrogen oxide (FeNO) and C-reactive protein (CRP) in serum among day care centre staff

Laboratory Test Results in Patients with Workplace Moisture Damage Associated Symptoms—The SAMDAW Study

The mechanisms of health effects of moisture damage (MD) are unclear, but inflammatory responses have been suspected. The usefulness of laboratory and allergy tests among patients in secondary healthcare with symptoms associated with workplace MD were examined. Full blood count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), total serum immunoglobulin E (IgE), fractional exhaled nitric oxide (FeNO), and skin prick testing were assessed and analyzed in relation to multiple chemical sensitivity (MCS) and perceived stress in 99 patients and 48 controls. In analysis, t-tests, Mann-Whitney tests, and chi-squared tests were used. Minor clinically insignificant differences in blood counts were seen in patients and controls, but among patients with asthma an elevated neutrophil count was found in 19% with and only in 2% of patients without asthma (p = 0.003). CRP levels and ESR were low, and the study patients’ FeNO, total IgE, or allergic sensitization were not increased compared to controls. The level of stress was high among 26% of patients and 6% of controls (p = 0.005), and MCS was more common among patients (39% vs. 10%, p < 0.001). Stress or MCS were not significantly associated with laboratory test results. In conclusion, no basic laboratory or allergy test results were characteristic of this patient group, and neither inflammatory processes nor allergic sensitization were found to explain the symptoms among these patients. While the value of basic laboratory tests should not be ignored, the use of allergy tests does not seem necessary when symptoms are indicated to be workplace-related.

Fungi composition in settled dust associated with fractional exhaled nitric oxide in school children with asthma

Fungi exposure has been significantly linked to respiratory illness. However, numerous fungi taxa that are potentially allergenic still undocumented and leave a barrier to establishing a clear connection between exposure and health risks. This study aimed to evaluate the association of fungi composition in settled dust with fractional exhaled nitric oxide (FeNO) levels among school children with doctor-diagnosed asthma. A cross-sectional study was undertaken among secondary school students in eight schools in the urban area of Hulu Langat, Selangor, Malaysia. A total of 470 school children (aged 14 years old) were randomly selected and their FeNO levels were measured and allergic skin prick tests were conducted. The settled dust samples were collected and analysed by using metagenomic technique to determine the fungi composition. The general linear regression with complex sampling was employed to determine the interrelationship. In total, 2645 fungal operational taxonomic units (OTUs) were characterised from the sequencing process which belongs to Ascomycota (60.7 %), Basidiomycota (36.4 %), Glomeromycota (2.9 %) and Chytridiomycota (0.04 %). The top five mostly abundance in all dust samples were Aspergillus clavatus (27.2 %), followed by Hyphoderma multicystidium (12.2 %), Verrucoconiothyrium prosopidis (9.4 %), Ganoderma tuberculosum (9.2 %), and Heterochaete shearii (7.2 %). The regression results indicated that A. clavatus, Brycekendrickomyces acaciae, Candida parapsilosis, Hazslinszkyomyces aloes, H. multicystidium, H. shearii, Starmerella meliponinorum, V. prosopidis were associated in increased of FeNO levels among the asthmatic group at 0.992 ppb (95 % CI = 0.34-1.68), 2.887 ppb (95 % CI = 2.09-3.76), 0.809 ppb (95 % CI = 0.14-1.49), 0.647 ppb (95 % CI = 0.36-0.94), 1.442 ppb (95 % CI = 0.29-2.61), 1.757 ppb (95 % CI = 0.59-2.87), 1.092 ppb (95 % CI = 0.43-1.75) and 1.088 ppb (95 % CI = 0.51-1.62), respectively. To our knowledge, this is a new finding. The findings pointed out that metagenomics profiling of fungi could enhance our understanding of a complex interrelation between rare and unculturable fungi with airway inflammation.

Indoor microbiome and allergic diseases: From theoretical advances to prevention strategies

The prevalence of allergic diseases, such as asthma, rhinitis, eczema, and sick building syndrome (SBS), has increased drastically in the past few decades. Current medications can only relieve the symptoms but not cure these diseases whose development is suggested to be greatly impacted by the indoor microbiome. However, no study comprehensively summarizes the progress and general rules in the field, impeding subsequent translational application. To close knowledge gaps between theoretical research and practical application, we conducted a comprehensive literature review to summarize the epidemiological, environmental, and molecular evidence of indoor microbiome studies. Epidemiological evidence shows that the potential protective indoor microorganisms for asthma are mainly from the phyla Actinobacteria and Proteobacteria, and the risk microorganisms are mainly from Bacilli, Clostridia, and Bacteroidia. Due to extremely high microbial diversity and geographic variation, different health-associated species/genera are detected in different regions. Compared with indoor microbial composition, indoor metabolites show more consistent associations with health, including microbial volatile organic compounds (MVOCs), lipopolysaccharides (LPS), indole derivatives, and flavonoids. Therefore, indoor metabolites could be a better indicator than indoor microbial taxa for environmental assessments and health outcome prediction. The interaction between the indoor microbiome and environmental characteristics (surrounding greenness, relative humidity, building confinement, and CO2 concentration) and immunology effects of indoor microorganisms (inflammatory cytokines and pattern recognition receptors) are briefly reviewed to provide new insights for disease prevention and treatment. Widely used tools in indoor microbiome studies are introduced to facilitate standard practice and the precise identification of health-related targets.

Early age exposure to moisture and mould is related to FeNO at the age of 6 years

BACKGROUND

Exposure to indoor moisture damage and visible mold has been found to be associated with asthma and respiratory symptoms in several questionnaire-based studies by self-report. We aimed to define the prospective association between the early life exposure to residential moisture damage or mold and fractional exhaled nitric oxide (FeNO) and lung function parameters as objective markers for airway inflammation and asthma in 6-year-old children.

METHODS

Home inspections were performed in children's homes when infants were on average 5 months old. At age 6 years, data on FeNO (n = 322) as well as lung function (n = 216) measurements were collected. Logistic regression and generalized additive models were used for statistical analyses.

RESULTS

Early age major moisture damage and moisture damage or mold in the child's main living areas were significantly associated with increased FeNO levels (>75th percentile) at the age of 6 years (adjusted odds ratios, 95% confidence intervals, aOR (95% CI): 3.10 (1.35-7.07) and 3.16 (1.43-6.98), respectively. Effects were more pronounced in those who did not change residential address throughout the study period. For lung function, major structural damage within the whole home was associated with reduced FEV1 and FVC, but not with FEV1/FVC. No association with lung function was observed with early moisture damage or mold in the child's main living areas.

CONCLUSION

These results underline the importance of prevention and remediation efforts of moisture and mold-damaged buildings in order to avoid harmful effects within the vulnerable phase of the infants and children's immunologic development.

Microbial Agents in the Indoor Environment: Associations with Health

There is international consensus that damp buildings and indoor mould can increase the risk of asthma, rhinitis, bronchitis and respiratory tract infections but we do not know which types of microbial agents that are causing the observed adverse health effects. Microbial indoor exposure is a broader concept than microbial growth in buildings. Other sources of indoor microbial exposure include the outdoor environment, humans (crowdedness) and furry pet keeping. Microbial exposure can have different health effects depending on the dose, different exposure route, genetic disposition and the timing of exposure. Microbial stimulation linked to large microbial diversity in early life can protect against disease development, especially for allergic asthma and atopy. Protective effects are more often reported for bacterial exposure and adverse health effects are more often linked to mould exposure. There are many studies on health associations for indoor exposure to endotoxin, mainly from homes. The risk of getting atopic asthma may be less if you are exposed to endotoxin in childhood but the risk of non-atopic asthma may increase if exposed to endotoxin especially in adulthood. Moreover, genetic disposition modifies health effects of endotoxin. Epidemiological studies on muramic acid (from gram-positive bacteria) or ergosterol (from mould) are few. Studies on health effects of indoor exposure to beta-1-3-glucan (from mould) have conflicting results (positive as well as negative associations). Epidemiological studies on health effects of indoor exposure to mycotoxins are very few. Some studies have reported health associations for MVOC, but it is unclear to what extent MVOC has microbial sources in indoor environments. Many studies have reported health associations for fungal DNA, especially as a risk factor for childhood asthma at home. Since most studies on health effects of indoor exposure to mould, bacteria and microbial agents are cross-sectional, it is difficult to draw conclusions on causality. More prospective studies on indoor microbial exposure are needed and studies should include other indoor environments than homes, such as day care centers, schools, hospitals and offices.

Early age exposure to moisture damage and systemic inflammation at the age of 6 years

Cross-sectional studies have shown that exposure to indoor moisture damage and mold may be associated with subclinical inflammation. Our aim was to determine whether early age exposure to moisture damage or mold is prospectively associated with subclinical systemic inflammation or with immune responsiveness in later childhood. Home inspections were performed in children's homes in the first year of life. At age 6 years, subclinical systemic inflammation was measured by serum C-reactive protein (CRP) and blood leukocytes and immune responsiveness by ex vivo production of interleukin 1-beta (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α) in whole blood cultures without stimulation or after 24 hours stimulation with phorbol 12-myristate 13-acetate and ionomycin (PI), lipopolysaccharide (LPS), or peptidoglycan (PPG) in 251-270 children. Moisture damage in child's main living areas in infancy was not significantly associated with elevated levels of CRP or leukocytes at 6 years. In contrast, there was some suggestion for an effect on immune responsiveness, as moisture damage with visible mold was positively associated with LPS-stimulated production of TNF-α and minor moisture damage was inversely associated with PI-stimulated IL-1β. While early life exposure to mold damage may have some influence on later immune responsiveness, it does not seem to increase subclinical systemic inflammation in later life.

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

Few health studies exist on dampness and mould in schools in the tropics. We studied associations between fraction of exhaled nitric oxide (FeNO), respiratory symptoms and airway infections among students and dampness and fungal DNA in schools in Malaysia. A total of 368 randomly selected students from 32 classrooms in 8 secondary schools in Penang, Malaysia, participated (58% participation rate). Information on current respiratory symptoms and the home environment was collected by a standardised questionnaire. FeNO was measured by NIOX MINO (50ml/min). The classrooms were inspected and dust was collected by vacuuming on special filters and was analysed for five fungal DNA sequences by quantitative PCR. Linear mixed models and 3-level multiple logistic regression (school, classroom, student) were applied adjusting for demographic data and the home environment. Totally 10.3% reported doctor's diagnosed asthma, 15.1% current wheeze, 12.4% current asthma, 37.3% daytime breathlessness, 10.2% nocturnal breathlessness, 38.9% airway infections and 15.5% had pollen or furry pet allergy. The geometric mean of FeNO was 19.9ppb and 45% had elevated FeNO (>20ppb). Boys had higher levels of FeNO. Chinese had less daytime breathlessness than Malay (OR=0.30: p<0.001). Indoor carbon dioxide levels were low (380-720ppm). Dampness was observed in 18% of the classrooms and was associated with respiratory infections (OR=3.70; 95% CI 1.14-12.1) and FeNO (p=0.04). Aspergillus versicolor DNA was detected in 67% of the classrooms. Higher numbers of Aspergillus versicolor DNA in classroom dust were associated with wheeze (p=0.006), current asthma (p=0.002), respiratory infections (p=0.005) and elevated FeNO levels (p=0.02). In conclusion, respiratory symptoms were common among the students and the high FeNO levels indicate ongoing airway inflammation. Building dampness and the mould Aspergillus versicolor in schools in Malaysia can be risk factors for impaired respiratory health among the students.