Mold hysteria: origin of the hoax

Melinacidin-Producing Acrostalagmus luteoalbus, a Major Constituent of Mixed Mycobiota Contaminating Insulation Material in an Outdoor Wall

Occupants may complain about indoor air quality in closed spaces where the officially approved standard methods for indoor air quality risk assessment fail to reveal the cause of the problem. This study describes a rare genus not previously detected in Finnish buildings, Acrostalagmus, and its species A. luteoalbus as the major constituents of the mixed microbiota in the wet cork liner from an outdoor wall. Representatives of the genus were also present in the settled dust in offices where occupants suffered from symptoms related to the indoor air. One strain, POB8, was identified as A. luteoalbus by ITS sequencing. The strain produced the immunosuppressive and cytotoxic melinacidins II, III, and IV, as evidenced by mass spectrometry analysis. In addition, the classical toxigenic species indicating water damage, mycoparasitic Trichoderma, Aspergillus section Versicolores, Aspergillus section Circumdati, Aspergillus section Nigri, and Chaetomium spp., were detected in the wet outdoor wall and settled dust from the problematic rooms. The offices exhibited no visible signs of microbial growth, and the airborne load of microbial conidia was too low to explain the reported symptoms. In conclusion, we suggest the possible migration of microbial bioactive metabolites from the wet outdoor wall into indoor spaces as a plausible explanation for the reported complaints.

Allergic rhinitis: Disease characteristics and coping measures in Saudi Arabia

BACKGROUND

Despite allergic rhinitis (AR) being a highly prevalent disease, according to literature, it is often underdiagnosed or undertreated.

AIM

This study explored the disease characteristics of AR in the Saudi community and the non-conventional coping measures used to alleviate symptoms.

METHODS

The study was a nationwide cross-sectional study, using a self-report electronic survey distributed via social media networks in 2018. The survey included an explanatory letter and consent. The sample size comprised 3,458 participants and 2,849 adults had at least one of the four signs of AR, i.e. watery-nose, sneezing, nasal obstruction, itchy nose, watery eyes, in the past year, not related to cold/flu. The outcomes of the study were the triggers, pattern, severity and the classification of AR (2016 ARIA guidelines) and coping measures. Descriptive statistics, univariate analytic statistics and binary logistic regression analyses were conducted. The P-value was considered statistically significant at <0.05.

RESULTS

The leading reported trigger of AR was dust (74%, n = 2118), followed by pollen (17%, n = 477), mold (5%, n = 140) and fur (4%, n = 114). The prevalence of intermittent AR was (54%, n = 1,635), while that of persistent AR was (46%, n = 1,314). Almost one-third (34%, n = 959) complained of mild forms of AR, while others complained of moderate to severe forms (66%, n = 1890). The coping measures were mainly shower/humidification 368(12.9%) and herbal hot drinks 266(9.3%). Older participants (adj.OR = 1.3[1.1-1.5]) and overweight participants, (adj.OR = 1.2[1.1-1.4]) reported more persistent forms of rhinitis compared to their counter groups, (adj.P<0.001 and adj.P = 0.032) respectively. Female participants (adj.OR = 0.8[0.7-0.9]) had significantly milder forms of AR, in comparison to males, adj.P = 0.006.

CONCLUSION

This study presented the disease characteristics of self-reported AR and its associated factors in Saudi Arabia. Special attention should be paid to older age groups and overweight patients who reported persistent forms of AR. Males reported more severe and persistent forms of AR.

Chloroanisoles may explain mold odor and represent a major indoor environment problem in Sweden

Indoor mold odor is associated with adverse health effects, but the microbial volatiles underlying mold odor are poorly described. Here, chloroanisoles were studied as potential key players, being formed by microbial metabolism of chlorophenols in wood preservatives. Using a three-stage approach, we (i) investigated the occurrence of chloroanisoles in buildings with indoor air quality problems, (ii) estimated their frequency in Sweden, and (iii) evaluated the toxicological risk of observed chloroanisole concentrations. Analyses of 499 building materials revealed several chloroanisole congeners in various types of buildings from the 1950s to 1970s. Evaluation of Swedish records from this time period revealed three coinciding factors, namely an unprecedented nationwide building boom, national regulations promoting wood preservatives instead of moisture prevention, and use of chlorophenols in these preservatives. Chlorophenols were banned in 1978, yet analysis of 457 indoor air samples revealed several chloroanisole congeners, but at median air levels generally below 15 ng/m(3) . Our toxicological evaluation suggests that these concentrations are not detrimental to human health per se, but sufficiently high to cause malodor. Thereby, one may speculate that chloroanisoles in buildings contribute to adverse health effects by evoking odor which, enhanced by belief of the exposure being hazardous, induces stress-related and inflammatory symptoms.

Indoor fungal composition is geographically patterned and more diverse in temperate zones than in the tropics

Fungi are ubiquitous components of indoor human environments, where most contact between humans and microbes occurs. The majority of these organisms apparently play a neutral role, but some are detrimental to human lifestyles and health. Recent studies that used culture-independent sampling methods demonstrated a high diversity of indoor fungi distinct from that of outdoor environments. Others have shown temporal fluctuations of fungal assemblages in human environments and modest correlations with human activity, but global-scale patterns have not been examined, despite the manifest significance of biogeography in other microbial systems. Here we present a global survey of fungi from indoor environments (n = 72), using both taxonomic and phylogeny-informative molecular markers to determine whether global or local indoor factors determine indoor fungal composition. Contrary to common ecological patterns, we show that fungal diversity is significantly higher in temperate zones than in the tropics, with distance from the equator being the best predictor of phylogenetic community similarity. Fungal composition is significantly auto-correlated at the national and hemispheric spatial scales. Remarkably, building function has no significant effect on indoor fungal composition, despite stark contrasts between architecture and materials of some buildings in close proximity. Distribution of individual taxa is significantly range- and latitude-limited compared with a null model of randomized distribution. Our results suggest that factors driving fungal composition are primarily global rather than mediated by building design or function.

Mold and human health: separating the wheat from the chaff

The term "mold" is utilized to define the ubiquitous fungal species commonly found in household dust and observed as visible multicellular filaments. Several well-defined human diseases are known to be caused or exacerbated by mold or by exposure to their byproducts. Among these, a solid connection has been established with infections, allergic bronchopulmonary aspergillosis, allergic fungal rhinosinusitis, hypersensitivity pneumonitis, and asthma. In the past decades, other less-defined and generally false conditions have also been ascribed to mold. We will herein review and critically discuss the available evidence on the influence of mold on human health.

Patients referred to an indoor air health clinic: exposure to water-damaged buildings causes an increase of lymphocytes in bronchoalveolar lavage and a decrease of CD19 leucocytes in peripheral blood

BACKGROUND

Respiratory and other symptoms are often associated with exposure to microbes present in water-damaged buildings.

MATERIAL AND METHODS

We examined 82 consecutive patients referred to the Indoor Air Clinic, Helsinki University Hospital, due to symptoms suspected of having been caused by long-term exposure to water damage in the home or workplace. Exposure to water damage was assessed by building inspections and microbial analyses as needed. Bronchoalveolar lavage, lung function measurements, skin prick tests to inhalant allergens and radiological examinations were performed in all patients. Leucocyte subsets in peripheral blood were analysed in 35 patients.

RESULTS

Marked water damage was detected in the homes or workplaces of 47 (59%) patients; the remaining 34 patients formed the control group. The exposed group expressed more symptoms in total than the control group: fatigue, conjunctival symptoms, rhinitis with sinusitis, recurrent bronchitis and asthma were more common in the exposed group, but a significant difference was seen only for headache. In BAL (bronchoalveolar lavage) samples, lymphocytes represented 25% of the total cell population in non-smoking-exposed patients compared with 12% in control patients (p=0.004). In peripheral blood, CD19 leucocytes were significantly decreased in the exposed group (7.5% versus 12.3%; p<0.01).

CONCLUSIONS

Confirmed exposure to water damage was associated with an increase in symptoms. Exposure to water damage caused a significant change in the cellular composition in BAL fluid (lymphocytosis) and blood (decrease of CD19 cells). The depletion of CD19 leucocytes in peripheral blood may indicate an active immune response in the lungs.