Adverse human health effects associated with molds in the indoor environment

Assessment of mould remediation in a healthcare setting following extensive flooding

BACKGROUND

A new hospital building was close to completion when a large pipe carrying clean water broke, causing extensive flooding.

AIM

To determine the flood-associated fungal risk to susceptible patients who would use that building.

METHODS

Though standard flood remediation by the builders was relatively straightforward, there was no model for specialist assessment of patient risk due to the flood-associated mould growth. As levels of background airborne fungal spores can be expected to vary significantly over time, we could not use absolute levels to indicate either an excess of airborne fungal spores or successful remediation. Therefore it was decided to use weekly settle plates, exposed at the same time in flooded (test) and equivalent non-flooded (control) areas to compensate for variations in background levels. Flood-related risk was estimated by the ratio between fungal colonies on the test and control sets of settle plates, rather than absolute number.

FINDINGS

Whereas the physical flood remediation, including the use of 'anti-fungal' treatments, was completed in three weeks post flooding, fungal contamination in flooded areas took 38 weeks to return to control levels and remained so for a further six weeks of observation.

CONCLUSION

By the use of this method, we were able to assure the absence of flood-associated fungal risk to susceptible patients who would use that building. We recommend that infection prevention and control teams consider using this approach should they be faced with similar situations.

Efficacy of dupilumab in patients with uncontrolled, moderate-to-severe asthma with fungal sensitization

BACKGROUND

Fungal sensitization (FS) exacerbates asthma in patients who have elevated type 2 inflammatory response. Dupilumab, a fully human monoclonal antibody, blocks the shared receptor component for interleukin (IL)-4 and IL-13, key and central drivers of type 2 inflammation in multiple diseases.

OBJECTIVE

This post hoc analysis, funded by the manufacturers of dupilumab, was conducted to assess dupilumab efficacy in patients from the phase 3 LIBERTY ASTHMA QUEST trial (NCT02414854) and TRAVERSE open-label extension (NCT02134028) study who had uncontrolled, moderate-to-severe asthma with type 2 inflammatory phenotype (defined as blood eosinophil count ≥150 cells/μL or FeNO ≥25 ppb) and with FS (defined as IgE specific to Alternaria alternata, Aspergillus fumigatus or Cladosporium herbarum >0.35 IU/mL).

METHODS

We evaluated annualized rate of severe exacerbations (AER), change from baseline in pre-bronchodilator (BD) forced expiratory volume in 1 s (FEV1 ), asthma control (per 5-item Asthma Control Questionnaire [ACQ-5]) and biomarker levels (blood eosinophil count, fractional exhaled nitric oxide [FeNO], total IgE, fungal-specific IgEs, thymus and activation-regulated chemokine [TARC] and eotaxin-3).

RESULTS

Dupilumab vs. placebo reduced AER, improved pre-BD FEV1 and asthma control (ACQ-5), and reduced serum IgE levels, blood eosinophil count, TARC, eotaxin-3 and FeNO in patients both with and without FS after 52 weeks of treatment in QUEST. Reductions in asthma exacerbation rates and improvements in all other variables were sustained over the TRAVERSE open-label extension study.

CONCLUSION

Dupilumab demonstrated efficacy during prolonged treatment in patients with uncontrolled, moderate-to-severe asthma with FS.

Intensive poultry farming: A review of the impact on the environment and human health

Poultry farming is one of the most efficient animal husbandry methods and it provides nutritional security to a significant number of the world population. Using modern intensive farming techniques, global production has reached 133.4 mil. t in 2020, with a steady growth each year. Such intensive growth methods however lead to a significant environmental footprint. Waste materials such as poultry litter and manure can pose a serious threat to environmental and human health, and need to be managed properly. Poultry production and waste by-products are linked to NH₃, N₂O and CH₄ emissions, and have an impact on global greenhouse gas emissions, as well as animal and human health. Litter and manure can contain pesticide residues, microorganisms, pathogens, pharmaceuticals (antibiotics), hormones, metals, macronutrients (at improper ratios) and other pollutants which can lead to air, soil and water contamination as well as formation of antimicrobial/multidrug resistant strains of pathogens. Dust emitted from intensive poultry production operations contains feather and skin fragments, faeces, feed particles, microorganisms and other pollutants, which can adversely impact poultry health as well as the health of farm workers and nearby inhabitants. Fastidious odours are another problem that can have an adverse impact on health and quality of life of workers and surrounding population. This study discusses the current knowledge on the impact of intensive poultry farming on environmental and human health, as well as taking a look at solutions for a sustainable future.

Failure of chelator-provoked urine testing results to predict heavy metal toxicity in a prospective cohort of patients referred for medical toxicology evaluation

INTRODUCTION

Provoked urine testing (PUT), involving chelating agent administration prior to measuring urine metal excretion levels, is used by some alternative health care practitioners to diagnose patients with heavy metal poisoning. Multiple medical societies have advised against this practice due to its presumed unreliability, expense, and lack of validation. However, no prospective study of the predictive value of PUT for heavy metal poisoning has been undertaken.

METHODS

This study utilized the Toxicology Consortium's prospective case registry to evaluate the reliability of PUT for diagnosing heavy metal poisoning. Inclusion criteria were toxicology clinic patients with PUT results who were subsequently evaluated by a board-certified medical toxicologist and had a determination made regarding whether their signs and symptoms were likely related or unrelated to toxicologic exposures. The primary outcome was the positive predictive value of PUT for heavy metal toxicity as diagnosed by the evaluating medical toxicologist. Patients presenting to participating toxicology clinics without PUT served as a comparison group.

RESULTS

74 of 106 cases presenting with PUT results met inclusion criteria and were analyzed. 15 cases were determined by the examining toxicologist to be likely related to a toxicologic exposure. Only three cases were found to be related to heavy metal exposure, giving a positive predictive value of 4.3%. 20.2% of patients with PUT were found to have signs or symptoms related to any toxicologic exposure, compared to 14.3% of clinic patients without PUT. Demographics of toxicology clinic patients with and without PUT results were not significantly different except for age.

DISCUSSION

Our results provide empiric support that PUT is an inaccurate predictor of a diagnosis of heavy metal poisoning by a board-certified medical toxicologist. Given the inability to properly interpret PUT results along with the increased cost burden and risk of false positives, PUT should not be performed.

Impact of negative pressure system on microbiological air quality in a Central Sterile Supply Department

OBJECTIVE

Guidelines recommend that the cleaning area in a Central Sterile Supply Department (CSSD) maintain a negative pressure of the environmental air, but how much this system can impact the contamination of the air by bioaerosols in the area is not known. The objective of this study was to assess the impact of negative pressure on CSSD by evaluating the microbiological air quality of this sector.

METHODS

Microbiological air samples were collected in two CSSD in the same hospital: one with and one without a negative air pressure system. Outdoor air samples were collected as a comparative control. Andersen six-stage air sampler was used to obtain the microbiological air samples.

RESULTS

The concentration of bioaerosols in the CSSD without negative pressure was 273.15 and 206.71 CFU/m3 , while in the CSSD with negative pressure the concentration of bioaerosols was 116.96 CFU/m3 and 131.10 CFU/m3 . The number of isolated colonies in the negative pressure CSSD was significantly lower (P = .01541).

CONCLUSION

The findings showed that the negative pressure system in the CSSD cleaning area contributed to the quantitative reduction in bioaerosols. However, the concentration of bioaerosols was lower than that established in the guideline for indoor air quality of many countries. Therefore, it cannot be concluded that CSSDs which do not have a negative pressure system in their cleaning area offer occupational risk.

Allergenicity assessment of fungal species using immunoclinical and proteomic techniques: a study on Fusarium lateritium

Airborne fungal spores are extensively reported as the elicitors of respiratory allergies in human. Fusarium lateritium is one such fungal species reported for eliciting significant skin prick results from India. The present study aims to analyze the allergenic potential of F. lateritium followed by the identification of allergens. The total protein of F. lateritium was subjected to 1dimensional (1D) and 2D gel electrophoresis followed by corresponding IgE-specific immunoblots. We found 8 immunoreactive bands/zones in (1D) immunoblot using 11 F. lateritium-sensitised patient sera. In 1D immunoblot, a 34 kDa band was detected in >80% of the patients and hence considered as a potential allergen of F. lateritium. Corresponding 34 kDa spot in 2D-immunoblot was analyzed by mass spectrometric analysis and identified as Glyceraldehyde 3-phosphate dehydrogenase. The identified F. lateritium allergen holds the potential to instigate vaccine development for immunotherapy of F. lateritium sensitized patients.

Mold inhalation causes innate immune activation, neural, cognitive and emotional dysfunction

Individuals living or working in moldy buildings complain of a variety of health problems including pain, fatigue, increased anxiety, depression, and cognitive deficits. The ability of mold to cause such symptoms is controversial since no published research has examined the effects of controlled mold exposure on brain function or proposed a plausible mechanism of action. Patient symptoms following mold exposure are indistinguishable from those caused by innate immune activation following bacterial or viral exposure. We tested the hypothesis that repeated, quantified doses of both toxic and nontoxic mold stimuli would cause innate immune activation with concomitant neural effects and cognitive, emotional, and behavioral symptoms. We intranasally administered either 1) intact, toxic Stachybotrys spores; 2) extracted, nontoxic Stachybotrys spores; or 3) saline vehicle to mice. As predicted, intact spores increased interleukin-1β immunoreactivity in the hippocampus. Both spore types decreased neurogenesis and caused striking contextual memory deficits in young mice, while decreasing pain thresholds and enhancing auditory-cued memory in older mice. Nontoxic spores also increased anxiety-like behavior. Levels of hippocampal immune activation correlated with decreased neurogenesis, contextual memory deficits, and/or enhanced auditory-cued fear memory. Innate-immune activation may explain how both toxic mold and nontoxic mold skeletal elements caused cognitive and emotional dysfunction.

Characterization and pro-inflammatory potential of indoor mold particles

A number of epidemiological studies find an association between indoor air dampness and respiratory health effects. This is often suggested to be linked to enhanced mold growth. However, the role of mold is obviously difficult to disentangle from other dampness-related exposure including microbes as well as non-biological particles and chemical pollutants. The association may partly be due to visible mycelial growth and a characteristic musty smell of mold. Thus, the potential role of mold exposure should be further explored by evaluating information from experimental studies elucidating possible mechanistic links. Such studies show that exposure to spores and hyphal fragments may act as allergens and pro-inflammatory mediators and that they may damage airways by the production of toxins, enzymes, and volatile organic compounds. In the present review, we hypothesize that continuous exposure to mold particles may result in chronic low-grade pro-inflammatory responses contributing to respiratory diseases. We summarize some of the main methods for detection and characterization of fungal aerosols and highlight in vitro research elucidating how molds may induce toxicity and pro-inflammatory reactions in human cell models relevant for airway exposure. Data suggest that the fraction of fungal hyphal fragments in indoor air is much higher than that of airborne spores, and the hyphal fragments often have a higher pro-inflammatory potential. Thus, hyphal fragments of prevalent mold species with strong pro-inflammatory potential may be particularly relevant candidates for respiratory diseases associated with damp/mold-contaminated indoor air. Future studies linking of indoor air dampness with health effects should assess the toxicity and pro-inflammatory potential of indoor air particulate matter and combined this information with a better characterization of biological components including hyphal fragments from both pathogenic and non-pathogenic mold species. Such studies may increase our understanding of the potential role of mold exposure.

Comparison of the performance of ITS1 and ITS2 as barcodes in amplicon-based sequencing of bioaerosols

This paper presents the performance of two eukaryotic genomic ribosomal regions, ITS1 and ITS2, in describing fungal diversity in aerosol samples using amplicon-based High-Throughput Sequencing (HTS). Composting sites, biomethanization facilities, and dairy farms, all affected by the presence of fungi, were visited to collect air samples. The amplicon-based HTS approach is a target enrichment method that relies on the amplification of a specific target using particular primers before sequencing. Thus, the results are highly dependent on the quality of amplification. For this reason, the authors of this paper used a shotgun metagenomic approach to compare its outcome with the amplicon-based method. Indeed, shotgun metagenomic does not rely on any amplification prior to sequencing, because all genes are sequenced without a specific target. In addition, culture methods were added to the analyses in biomethanization and dairy farms samples to validate their contribution to fungal diversity of aerosols. The results obtained are unequivocal towards ITS1 outperformance to ITS2 in terms of richness, and taxonomic coverage. The differential abundance analysis did demonstrate that some taxa were exclusively detected only by ITS2, and vice-versa for ITS1. However, the shotgun metagenomic approach showed a taxonomic profile more resembling to ITS1 than ITS2. Based on these results, neither of the barcodes evaluated is perfect in terms of distinguishing all species. Using both barcodes offers a broader view of the fungal aerosol population. However, with the actual knowledge, the authors strongly recommend using ITS1 as a universal fungal barcode for quick general analyses of diversity and when limited financial resources are available, primarily due its ability to capture taxonomic profiles similar to those obtained using the shotgun metagenomic. The culture comparison with amplicon-based sequencing showed the complementarity of both approaches in describing the most abundant taxa.

Recovery of Fungal Cells from Air Samples: a Tale of Loss and Gain

There are limitations in establishing a direct link between fungal exposure and health effects due to the methodology used, among other reasons. Culture methods ignore the nonviable/uncultivable fraction of airborne fungi. Molecular methods allow for a better understanding of the environmental health impacts of microbial communities. However, there are challenges when applying these techniques to bioaerosols, particularly to fungal cells. This study reveals that there is a loss of fungal cells when samples are recovered from air using wet samplers and aimed to create and test an improved protocol for concentrating mold spores via filtration prior to DNA extraction. Results obtained using the new technique showed that up to 3 orders of magnitude more fungal DNA was retrieved from the samples using quantitative PCR. A sequencing approach with MiSeq revealed a different diversity profile depending on the methodology used. Specifically, 8 fungal families out of 19 families tested were highlighted to be differentially abundant in centrifuged and filtered samples. An experiment using laboratory settings showed the same spore loss during centrifugation for Aspergillus niger and Penicillium roquefortii strains. We believe that this work helped identify and address fungal cell loss during processing of air samples, including centrifugation steps, and propose an alternative method for a more accurate evaluation of fungal exposure and diversity.IMPORTANCE This work shed light on a significant issue regarding the loss of fungal spores when recovered from air samples using liquid medium and centrifugation to concentrate air particles before DNA extraction. We provide proof that the loss affects the overall fungal diversity of aerosols and that some taxa are differentially more affected than others. Furthermore, a laboratory experiment confirmed the environmental results obtained during field sampling. The filtration protocol described in this work offers a better description of the fungal diversity of aerosols and should be used in fungal aerosol studies.

Effects of indoor environmental parameters related to building heating, ventilation, and air conditioning systems on patients' medical outcomes: A review of scientific research on hospital buildings

The indoor environment of a mechanically ventilated hospital building controls infection rates as well as influences patients' healing processes and overall medical outcomes. This review covers the scientific research that has assessed patients' medical outcomes concerning at least one indoor environmental parameter related to building heating, ventilation, and air conditioning (HVAC) systems, such as indoor air temperature, relative humidity, and indoor air ventilation parameters. Research related to the naturally ventilated hospital buildings was outside the scope of this review article. After 1998, a total of 899 papers were identified that fit the inclusion criteria of this study. Of these, 176 papers have been included in this review to understand the relationship between the health outcomes of a patient and the indoor environment of a mechanically ventilated hospital building. The purpose of this literature review was to summarize how indoor environmental parameters related to mechanical ventilation systems of a hospital building are impacting patients. This review suggests that there is a need for future interdisciplinary collaborative research to quantify the optimum range for HVAC parameters considering airborne exposures and patients' positive medical outcomes.

Fungal aerosols at dairy farms using molecular and culture techniques

Occupational exposure to harmful bioaerosols in industrial environments is a real threat to the workers. In particular, dairy-farm workers are exposed to high levels of fungal bioaerosols on a daily basis. Associating bioaerosol exposure and health problems is challenging and adequate exposure monitoring is a top priority for aerosol scientists. Using only culture-based tools does not express the overall microbial diversity and underestimate the large spectrum of microbes in bioaerosols and therefore the extended fungal profile that farmers are exposed to. The aim of this study was to provide an in-depth characterization of fungal exposure at Eastern Canadian dairy farms using qPCR and high-throughput sequencing methods. Specific primers were used for the quantification of Penicillium/Aspergillus and Aspergillus fumigatus in dairy farms air samples. Illumina Miseq sequencing of the ITS1 region provided sequences for the diversity analyses. The minimum and maximum concentration of Penicillium/Aspergillus ranged from 4.6 × 10⁶ to 9.4 × 10⁶ gene copies/m³ and from 1 × 10⁴ gene copies/m³ to 4.8 × 10⁵ gene copies/m³ for Aspergillus fumigatus, respectively. Differences in the diversity profiles of the five dairy farms support the idea that the novel approach identifies a large number of fungal taxa. The most striking differences include Microascus, Piptoporus, Parastagonospora, Dissoconium, Microdochium, Tubilicrinis, Ganoderma, Ustilago, Phlebia and Wickerhamomyces. The presence of a diverse portrait of fungi in air may represent a health risk for workers who are exposed on a daily basis. The broad spectrum of fungi detected in this study includes many known pathogens like Aspergillus, Acremonium, Alternaria and Fusarium. Adequate monitoring of bioaerosol exposure is necessary to evaluate and minimize risks.

Indoor air pollution and the contribution of biosensors

A vast majority of people today spend more time indoors than outdoors. However, the air quality indoors may be as bad as or even worse than the air quality outside. This is due to the continuous circulation of the same air without proper ventilation and filtration systems, causing a buildup of pollutants. As such, indoor air quality monitoring should be considered more seriously. Indoor air quality (IAQ) is a measure of the air quality within and around buildings and relates to the health and comfort of building occupants. To determine the IAQ, computer modeling is done to simulate the air flow and human exposure to the pollutant. Currently, very few instruments are available to measure the indoor air pollution index. In this paper, we will review the list of techniques available for measuring IAQ, but our emphasis will be on indoor air toxicity monitoring.

Rapid and Sensitive Detection of Aspergillus niger Using a Single-Mediator System Combined with Redox Cycling

Rapid and sensitive mold detection is becoming increasingly important, especially in indoor environments. Common mold detection methods based on double-mediated electron transfer between an electrode and molds are not highly sensitive and reproducible, although they are rapid and simple. Here, we report a sensitive and reproducible detection method specific to Aspergillus niger ( A. niger), based on a single-mediator system combined with electrochemical-chemical (EC) redox cycling. Intracellular NAD(P)H-oxidizing enzymes in molds can convert electro-inactive hydroxy-nitro(so)arenes into electro-active hydroxy-aminoarenes. Since the membrane and wall of A. niger is well permeable to both a substrate (4-nitro-1-naphthol) and a reduced product (4-amino-1-naphthol) in tris buffer (pH 7.5) solution, the electrochemical signal is increased in the presence of A. niger due to two reactions: (i) enzymatic reduction of the substrate to the reduced product and (ii) electrochemical oxidation of the reduced product to an oxidized product. When a reducing agent (NADH) is present in the solution, the oxidized product is reduced back to the reduced product and then electrochemically reoxidized. This EC redox cycling significantly amplifies the electrochemical signal. Moreover, the background level is low and highly reproducible because the substrate and the reducing agent are electro-inactive at an applied potential of 0.20 V. The calculated detection limit for A. niger in a common double-mediator system consisting of Fe(CN)₆^3- and menadione is ∼2 × 10⁴ colony-forming unit (CFU)/mL, but the detection limit in the single-mediator system combined with EC redox cycling is ∼2 × 10³ CFU/mL, indicating that the newly developed single-mediator system is more sensitive. Importantly, the detection method requires only an incubation period of 10 min and does not require a washing step, an electrode modification step, or a specific probe.

From Office Environmental Stressors to Work Performance: The Role of Work Patterns

Background: Different studies have shown a relationship between office environmental stressors and performance. However, studying environmental stress in the workplace requires analyzing more specific patterns to generate knowledge about the type of employees who are more or less vulnerable to environmental stressors. The present study analyzes the mediating role of health symptoms and negative emotions in the relationship between stressors and performance in different work patterns (task complexity and interactivity). Methods: There were 83 office workers (n = 603 time points) that took part in a diary study with multilevel design. Results: The appraisal of the environmental stressors is positively related to health-related symptoms, which in turn increase negative emotions, and then decrease the performance of workers who perform complex tasks and interact frequently with other people at work. This mediation is not significant when office workers do not interact frequently with other people at work and/or perform simple, rather than complex tasks. Conclusions: Work patterns play an important role when studying the mediating role of health-related symptoms and negative emotions in the relationship between the appraisal of environmental stressors and performance in office workers. In other words, employees in the 'interactive and complex' pattern are more vulnerable to the negative effects of office stressors on performance.

Mold and Human Health: a Reality Check

There are possibly millions of mold species on earth. The vast majority of these mold spores live in harmony with humans, rarely causing disease. The rare species that does cause disease does so by triggering allergies or asthma, or may be involved in hypersensitivity diseases such as allergic bronchopulmonary aspergillosis or allergic fungal sinusitis. Other hypersensitivity diseases include those related to occupational or domiciliary exposures to certain mold species, as in the case of Pigeon Breeder's disease, Farmer's lung, or humidifier fever. The final proven category of fungal diseases is through infection, as in the case of onchomycosis or coccidiomycosis. These diseases can be treated using anti-fungal agents. Molds and fungi can also be particularly important in infections that occur in immunocompromised patients. Systemic candidiasis does not occur unless the individual is immunodeficient. Previous reports of "toxic mold syndrome" or "toxic black mold" have been shown to be no more than media hype and mass hysteria, partly stemming from the misinterpreted concept of the "sick building syndrome." There is no scientific evidence that exposure to visible black mold in apartments and buildings can lead to the vague and subjective symptoms of memory loss, inability to focus, fatigue, and headaches that were reported by people who erroneously believed that they were suffering from "mycotoxicosis." Similarly, a causal relationship between cases of infant pulmonary hemorrhage and exposure to "black mold" has never been proven. Finally, there is no evidence of a link between autoimmune disease and mold exposure.

Filter forensics: microbiota recovery from residential HVAC filters

BACKGROUND

Establishing reliable methods for assessing the microbiome within the built environment is critical for understanding the impact of biological exposures on human health. High-throughput DNA sequencing of dust samples provides valuable insights into the microbiome present in human-occupied spaces. However, the effect that different sampling methods have on the microbial community recovered from dust samples is not well understood across sample types. Heating, ventilation, and air conditioning (HVAC) filters hold promise as long-term, spatially integrated, high volume samplers to characterize the airborne microbiome in homes and other climate-controlled spaces. In this study, the effect that dust recovery method (i.e., cut and elution, swabbing, or vacuuming) has on the microbial community structure, membership, and repeatability inferred by Illumina sequencing was evaluated.

RESULTS

The results indicate that vacuum samples captured higher quantities of total, bacterial, and fungal DNA than swab or cut samples. Repeated swab and vacuum samples collected from the same filter were less variable than cut samples with respect to both quantitative DNA recovery and bacterial community structure. Vacuum samples captured substantially greater bacterial diversity than the other methods, whereas fungal diversity was similar across all three methods. Vacuum and swab samples of HVAC filter dust were repeatable and generally superior to cut samples. Nevertheless, the contribution of environmental and human sources to the bacterial and fungal communities recovered via each sampling method was generally consistent across the methods investigated.

CONCLUSIONS

Dust recovery methodologies have been shown to affect the recovery, repeatability, structure, and membership of microbial communities recovered from dust samples in the built environment. The results of this study are directly applicable to indoor microbiota studies utilizing the filter forensics approach. More broadly, this study provides a better understanding of the microbial community variability attributable to sampling methodology and helps inform interpretation of data collected from other types of dust samples collected from indoor environments.

Fungal raw materials used to produce allergen extracts

OBJECTIVE

To review the topic of fungal raw materials used for the production of allergen extracts and the associated challenges and highlight candidate areas for development before standardized fungal allergen extracts can be commercially produced.

DATA SOURCES

A PubMed search was performed using focused keywords and combined with a review of regulatory documents and industry guidelines. Several books on mycology also were consulted.

STUDY SELECTIONS

The information obtained through the literature, books, and industry was scrutinized and combined with personal experience and expertise to write this article.

RESULTS

Fungi are complex ubiquitous organisms on Earth. They are beneficial and detrimental for humans. Fungi can cause hypersensitivity reactions, including types I, III, and IV. The procurement of fungal raw materials to prepare allergen extracts for diagnosis and possible allergen immunotherapy is complex owing to the intrinsic nature of fungi and their complex genome. Allergen manufacturers produce allergen extracts with variable qualitative and quantitative compositions, which can lead to unpredictable clinical outcomes.

CONCLUSION

The clinician should be aware of the factors responsible for the qualitative and quantitative compositions of fungal allergen extracts and the reasons that currently preclude their standardization. Scientific advances and collaboration and cooperation between allergen manufacturing companies and regulatory agencies are necessary to improve the quality and consistency of fungal extracts. Moreover, clinicians should understand the limitations of currently available fungal extracts.

Cold homes, fuel poverty and energy efficiency improvements: A longitudinal focus group approach

Cold homes and fuel poverty have been identified as factors in health and social inequalities that could be alleviated through energy efficiency interventions. Research on fuel poverty and the health impacts of affordable warmth initiatives have to date primarily been conducted using quantitative and statistical methods, limiting the way how fuel poverty is understood. This study took a longitudinal focus group approach that allowed exploration of lived experiences of fuel poverty before and after an energy efficiency intervention. Focus group discussions were held with residents from three low-income communities before (n = 28) and after (n = 22) they received energy efficiency measures funded through a government-led scheme. The results show that improving the energy efficiency of homes at risk of fuel poverty has a profound impact on wellbeing and quality of life, financial stress, thermal comfort, social interactions and indoor space use. However, the process of receiving the intervention was experienced by some as stressful. There is a need for better community engagement and communication to improve the benefits delivered by fuel poverty programmes, as well as further qualitative exploration to better understand the wider impacts of fuel poverty and policy-led intervention schemes.

Mold allergy: is it real and what do we do about it?

INTRODUCTION

fungi produce substances that contain pathogen-associated molecular patterns (pamps) and damage-associated molecular patterns (damps) which bind to pattern recognition receptors, stimulating innate immune responses in humans. they also produce allergens that induce production of specific ige. Areas covered: In this review we cover both innate and adaptive immune responses to fungi. Some fungal products can activate both innate and adaptive responses and in doing so, cause an intense and complex health effects. Methods of testing for fungal allergy and evidence for clinical treatment including environmental control are also discussed. In addition, we describe controversial issues including the role of Stachybotrys and mycotoxins in adverse health effects. Expert commentary: Concerns about long-term exposure to fungi have led some patients, attorneys and fungus advocates to promote fears about a condition that has been termed toxic mold syndrome. This syndrome is associated with vague symptoms and is believed to be due to exposure to mycotoxins, though this connection has not been proven. Ultimately, more precise methods are needed to measure both fungal exposure and the resulting health effects. Once that such methods become available, much of the speculation will be replaced by knowledge.

Microbiota and Particulate Matter Assessment in Portuguese Optical Shops Providing Contact Lens Services

The aim of this work was to assess the microbiota (fungi and bacteria) and particulate matter in optical shops, contributing to a specific protocol to ensure a proper assessment. Air samples were collected through an impaction method. Surface and equipment swab samples were also collected side-by-side. Measurements of particulate matter were performed using portable direct-reading equipment. A walkthrough survey and checklist was also applied in each shop. Regarding air sampling, eight of the 13 shops analysed were above the legal requirement and 10 from the 26 surfaces samples were overloaded. In three out of the 13 shops fungal contamination in the analysed equipment was not detected. The bacteria air load was above the threshold in one of the 13 analysed shops. However, bacterial counts were detected in all sampled equipment. Fungi and bacteria air load suggested to be influencing all of the other surface and equipment samples. These results reinforce the need to improve air quality, not only to comply with the legal requirements, but also to ensure proper hygienic conditions. Public health intervention is needed to assure the quality and safety of the rooms and equipment in optical shops that perform health interventions in patients.

Volatile organic compounds emitted by filamentous fungi isolated from flooded homes after Hurricane Sandy show toxicity in a Drosophila bioassay

Superstorm Sandy provided an opportunity to study filamentous fungi (molds) associated with winter storm damage. We collected 36 morphologically distinct fungal isolates from flooded buildings. By combining traditional morphological and cultural characters with an analysis of ITS sequences (the fungal DNA barcode), we identified 24 fungal species that belong to eight genera: Penicillium (11 species), Fusarium (four species), Aspergillus (three species), Trichoderma (two species), and one species each of Metarhizium, Mucor, Pestalotiopsis, and Umbelopsis. Then, we used a Drosophila larval assay to assess possible toxicity of volatile organic compounds (VOCs) emitted by these molds. When cultured in a shared atmosphere with growing cultures of molds isolated after Hurricane Sandy, larval toxicity ranged from 15 to 80%. VOCs from Aspergillus niger 129B were the most toxic yielding 80% mortality to Drosophila after 12 days. The VOCs from Trichoderma longibrachiatum 117, Mucor racemosus 138a, and Metarhizium anisopliae 124 were relatively non-toxigenic. A preliminary analysis of VOCs was conducted using solid-phase microextraction-gas chromatography-mass spectrometry from two of the most toxic, two of the least toxic, and two species of intermediate toxicity. The more toxic molds produced higher concentrations of 1-octen-3-ol, 3-octanone, 3-octanol, 2-octen-1-ol, and 2-nonanone; while the less toxic molds produced more 3-methyl-1-butanol and 2-methyl-1-propanol, or an overall lower amount of volatiles. Our data support the hypothesis that at certain concentrations, some VOCs emitted by indoor molds are toxigenic.

The role of outdoor fungi on asthma hospital admissions in children and adolescents: A 5-year time stratified case-crossover analysis

BACKGROUND

Some fungal spores can trigger asthma exacerbation but knowledge of which outdoor fungal spores contribute to asthma hospitalisation is limited.

OBJECTIVES

To examine the role of outdoor fungal spores in child and adolescent asthma hospitalisations.

METHODS

We conducted a bi-directional time-stratified case-crossover study of child and adolescent asthma hospitalisations over 5 years. Conditional logistic regression assessed the role of 20 fungi taxa (Same day [L0] and lagged [L1-3]) adjusted for maximum temperature, humidity and grass pollen. Strata specific effects were explored if there was evidence of effect modification by age, sex, air pollutants or grass pollen. Non-linear effects examined with Generalized Additive Models.

RESULTS

Of 2098 children hospitalised for asthma, 60% were boys; mean age was 5.5±3.7 years. Fungal spore counts peaked during warm months. Regression models found weak associations with Coprinus [L0,L1: OR=1.03, 1.01-1.06], Periconia [L0: OR=1.03, 1.001-1.07] and Chaetomium [L2: OR=1.08, 1.0-1.2]. Sex appeared to act as an effect modifier with girls having stronger associations with Cladosporium, Coprinus and total fungi. Older adolescent (14-18 years) hospitalisation was significantly associated with Coprinus and Ustilago/smuts. Air pollutants and grass pollen did not appear to act as effect modifiers. Non-linearity was not detected.

CONCLUSION

There may be associations between some outdoor fungal spores and asthma hospitalisations. Further research needed to explore whether these findings can be replicated; and examine whether fungal sensitisation and/or human rhinovirus infections are associated with stronger effects. If findings are replicated, then the need to develop predictive models for fungal spore distribution and levels may become more important.

Galvanic microcells as control agent of indoor microorganisms

Today, fungicides are part of the basic tool kit for indoor surface maintenance. However, fungi develop resistance to fungicides, which consequently accelerates the evolution of virulence. Fungicides also carry the risk of adverse effects in humans. Galvanic microcells are a new tool for fungal control on indoor surfaces. We used two types of electrodes, Zn and Cu, with two potential anti-fungal mechanisms: the oligodynamic action of the metal ions themselves and the electricidal effect of the current between the electrodes. The size of the inhibition zone is related to the distance between the electrodes. We hypothesized that the unique geometric properties of the observed inhibition zone could be modelled using multi foci curve Cassini ovals. Moreover, the size of the inhibition zone possessed two maximum values, while the shape of the observed inhibition zones correlated with the shape of the electric field strength. The control activity of the galvanic microcells correlated with decreasing water content in building materials. Thus, this acute antifungal system works the best in damp building environments where the risk of fungal contamination is highest.

Subchronic exposures to fungal bioaerosols promotes allergic pulmonary inflammation in naïve mice

BACKGROUND

Epidemiological surveys indicate that occupants of mold contaminated environments are at increased risk of respiratory symptoms. The immunological mechanisms associated with these responses require further characterization.

OBJECTIVE

The aim of this study was to characterize the immunotoxicological outcomes following repeated inhalation of dry Aspergillus fumigatus spores aerosolized at concentrations potentially encountered in contaminated indoor environments.

METHODS

Aspergillus fumigatus spores were delivered to the lungs of naïve BALB/cJ mice housed in a multi-animal nose-only chamber twice a week for a period of 13 weeks. Mice were evaluated at 24 and 48 h post-exposure for histopathological changes in lung architecture, recruitment of specific immune cells to the airways, and serum antibody responses.

RESULT

Germinating A. fumigatus spores were observed in lungs along with persistent fungal debris in the perivascular regions of the lungs. Repeated exposures promoted pleocellular infiltration with concomitant epithelial mucus hypersecretion, goblet cell metaplasia, subepithelial fibrosis and enhanced airway hyperreactivity. Cellular infiltration in airways was predominated by CD4(+) T cells expressing the pro-allergic cytokine IL-13. Furthermore, our studies show that antifungal T cell responses (IFN-γ(+) or IL-17A(+) ) co-expressed IL-13, revealing a novel mechanism for the dysregulated immune response to inhaled fungi. Total IgE production was augmented in animals repeatedly exposed to A. fumigatus.

CONCLUSIONS & CLINICAL RELEVANCE

Repeated inhalation of fungal aerosols resulted in significant pulmonary pathology mediated by dynamic shifts in specific immune populations and their cytokines. These studies provide novel insights into the immunological mechanisms and targets that govern the health outcomes that result from repeated inhalation of fungal bioaerosols in contaminated environments.

The Black Yeast Exophiala dermatitidis and Other Selected Opportunistic Human Fungal Pathogens Spread from Dishwashers to Kitchens

We investigated the diversity and distribution of fungi in nine different sites inside 30 residential dishwashers. In total, 503 fungal strains were isolated, which belong to 10 genera and 84 species. Irrespective of the sampled site, 83% of the dishwashers were positive for fungi. The most frequent opportunistic pathogenic species were Exophiala dermatitidis, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Fusarium dimerum, and the Saprochaete/Magnusiomyces clade. The black yeast E. dermatitidis was detected in 47% of the dishwashers, primarily at the dishwasher rubber seals, at up to 10⁶ CFU/cm²; the other fungi detected were in the range of 10² to 10⁵ CFU/cm². The other most heavily contaminated dishwasher sites were side nozzles, doors and drains. Only F. dimerum was isolated from washed dishes, while dishwasher waste water contained E. dermatitidis, Exophiala oligosperma and Sarocladium killiense. Plumbing systems supplying water to household appliances represent the most probable route for contamination of dishwashers, as the fungi that represented the core dishwasher mycobiota were also detected in the tap water. Hot aerosols from dishwashers contained the human opportunistic yeast C. parapsilosis, Rhodotorula mucilaginosa and E. dermatitidis (as well as common air-borne genera such as Aspergillus, Penicillium, Trichoderma and Cladosporium). Comparison of fungal contamination of kitchens without and with dishwashers revealed that virtually all were contaminated with fungi. In both cases, the most contaminated sites were the kitchen drain and the dish drying rack. The most important difference was higher prevalence of black yeasts (E. dermatitidis in particular) in kitchens with dishwashers. In kitchens without dishwashers, C. parapsilosis strongly prevailed with negligible occurrence of E. dermatitidis. F. dimerum was isolated only from kitchens with dishwashers, while Saprochaete/Magnusiomyces isolates were only found within dishwashers. We conclude that dishwashers represent a reservoir of enriched opportunistic pathogenic species that can spread from the dishwasher into the indoor biome.

Are Some Fungal Volatile Organic Compounds (VOCs) Mycotoxins?

Volatile organic compounds (VOCs) are carbon-compounds that easily evaporate at room temperature. Toxins are biologically produced poisons; mycotoxins are those toxins produced by microscopic fungi. All fungi emit blends of VOCs; the qualitative and quantitative composition of these volatile blends varies with the species of fungus and the environmental situation in which the fungus is grown. These fungal VOCs, produced as mixtures of alcohols, aldehydes, acids, ethers, esters, ketones, terpenes, thiols and their derivatives, are responsible for the characteristic moldy odors associated with damp indoor spaces. There is increasing experimental evidence that some of these VOCs have toxic properties. Laboratory tests in mammalian tissue culture and Drosophila melanogaster have shown that many single VOCs, as well as mixtures of VOCs emitted by growing fungi, have toxic effects. This paper describes the pros and cons of categorizing toxigenic fungal VOCs as mycotoxins, uses genomic data to expand on the definition of mycotoxin, and summarizes some of the linguistic and other conventions that can create barriers to communication between the scientists who study VOCs and those who study toxins. We propose that "volatoxin" might be a useful term to describe biogenic volatile compounds with toxigenic properties.

Field evaluation of personal sampling methods for multiple bioaerosols

Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC) filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters) and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min). Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

Silver linings: a personal memoir about Hurricane Katrina and fungal volatiles

In the aftermath of Hurricane Katrina, the levees protecting New Orleans, Louisiana failed. Because approximately 80% of the city was under sea level, widespread flooding ensued. As a resident of New Orleans who had evacuated before the storm and a life-long researcher on filamentous fungi, I had known what to expect. After the hurricane I traveled home with a suitcase full of Petri dishes and sampling equipment so as to study the fungi that were "eating my house." Not only were surfaces covered with fungal growth, the air itself was full of concentrated mold odor, a smell that was orders of magnitude more funky than any damp, musty basement I had ever encountered. The smell made me feel bad and I had to take regular breaks as I sampled. Being a mycotoxin expert, I knew a fair amount about "sick building syndrome" but believed that it was difficult to get enough respiratory exposure to toxins to cause the array of symptoms associated with the syndrome. So why was I feeling sick? Some Scandinavian experts had hypothesized that mold volatile organic compounds (VOCs) might be the fungal metabolites to blame for sick building syndrome and the time in my smelly, mold infested home made me think they might be right. After securing a new job and establishing a new laboratory, I endeavored to test the hypothesis that some volatile mold metabolites might be toxic. My laboratory at Rutgers University has interrogated the role of VOCs in possible interkingdom toxicity by developing controlled microcosms for exposing simple genetic model organisms to the vapor phase of growing fungi. Both Arabidopsis thaliana and Drosophila melanogaster exhibit a range of toxic symptoms that vary with the species of fungus, the duration of exposure, and other experimental parameters. Moreover, low concentrations of chemical standards of individual fungal VOCs such as 1-octen-3-ol also exhibit varying toxicity and cause neurotoxicity in a Drosophila model. Collectively, these data suggest that fungal VOCs may contribute to some of the adverse health effects reported by people exposed to damp indoor environments and that biogenic gas phase molecules deserve increased attention by the research community.

Risk of Bioaerosol Contamination With Aspergillus Species Before and After Cleaning in Rooms Filtered With High-Efficiency Particulate Air Filters That House Patients With Hematologic Malignancy

Objective.

To examine the impact of cleaning and directional airflow on environmental contamination with Aspergillus species in hospital rooms filtered with high-efficiency particulate air (HEPA) filters that house patients with hematologic malignancy.

Design.

Detailed environmental assessment.

Setting.

A 475-bed tertiary cancer center in the southern United States.

Methods.

From April to October 2004, 1,258 surface samples and 627 bioaerosol samples were obtained from 74 HEPA-filtered rooms (in addition, 88 outdoor bioaerosol samples were obtained). Samples were collected from rooms cleaned within 1 hour after patient discharge and from rooms before cleaning. Positive and negative airflows were evaluated using air-current tubes at entrances to patient rooms.

Results.

Of 1,258 surface samples, 3.3% were positive for Aspergillus species. Univariate analysis showed no relationship between cleaning status and occurrence of Aspergillus species. Of 627 bioaerosol samples, 7.3% were positive for Aspergillus species. Multiple logistic analysis revealed independently significant associations with detection of Aspergillus species. Cleaned rooms positive for Aspergillus species had a higher geometric mean density of colonies than that of rooms sampled before cleaning (18.9 vs 5.5 colony-forming units [cfu] per cubic meter; P = .0047). Rooms with positive airflow had a detection rate for bioaerosol samples equivalent to that of rooms with negative airflow (7.3% vs 7.8%; P = .8). There was no significant difference in the density of Aspergillus species between rooms with negative airflow and rooms with positive airflow (12.5 vs 8.4 cfu/m3; P = .33).

Conclusions.

Concentration of bioaerosol contamination with Aspergillus species was increased in rooms sampled 1 hour after cleaning compared with rooms sampled before cleaning, suggesting a possible correlation between reentrained bioaerosols (ie, those suspended by activity in the room) after cleaning and the risk of nosocomial invasive aspergillosis.

Fungi in housefly (Musca domestica L.) as a disease risk indicator-A case study in South Africa

Houseflies are the commonest insects which have increasingly overcrowded human dwellings, particularly in rural areas and constitute a health hazard. In the environment they move back and forth by feeding and breeding on food commodities and filth. This may lead to the spread of diseases and also mycotoxin-producing fungi. Thus frequent exposure to the activity of such houseflies will have an impact on the welfare of humans. The study investigated the natural occurrence of fungal contamination in housefly samples captured from different households and pit toilets from a rural community in South Africa. Fungal contamination data were based on the prevalence, contamination level and morphological characteristics of the different identified species. A total of 497 fungal isolates of 15 genera including Aspergillus (37%), Fusarium (17%), Penicillium (21%), Alternaria (1.4%), Chrysosporium (2%), Cladosporium (0.2%), Curvularia (0.4%), Epicoccum (1%), Eupenicillium (1%), Moniliella (9%), Mucor (2%), Nigrospora (1%), Rhizopus (2%), Scopulariopsis (2%) and Yeasts (3%) were identified from the external surfaces of both female and male houseflies. The range of fungal contamination per total fungal count isolated from female and male houseflies were recorded with mean fungal load of 4.1×10(6), 8.4×10(6), 4.4×10(6), 3.3×10(5), 9.8×10(6), 2.2×10(4), 5.6×10(4), 2.9×10(6), 5.2×10(6), 4.7×10(6), 4.5×10(7), 4.6×10(6), 2.3×10(6), 4.9×10(7) and 6.4×10(6)CFU/ml, respectively. However, the range from The most dominant fungal isolates of the female housefly samples were Aspergillus flavus, Fusarium verticillioides, Penicillium verrucosum and Moniliella suaveolens, while A. flavus, Aspergillus parasiticus, F. verticillioides, Fusarium proliferatum and Penicillium aurantiogriseum were most prevalent in male samples. The study proves that housefly is a vector for fungal spores. Therefore, it is crucial to implement housefly-control measures to curb the spread of diseases.

Current asthma in schoolchildren is related to fungal spores in classrooms

BACKGROUND

The presence of visible mold in households is associated with asthma. However, the role of "classroom fungus" in the development of childhood asthma, as well as the fungal species that may lead to asthma, remains controversial. This nationwide school survey was conducted to investigate the correlation between fungal spores in classrooms and asthma in schoolchildren.

METHODS

From April to May 2011, a cross-sectional survey was conducted to assess allergic/asthmatic conditions in schoolchildren aged 6 to 15 years old in 44 schools across Taiwan. Personal histories and current asthmatic conditions were collected using a modified International Study of Asthma and Allergies in Childhood questionnaire. Fungal spores in classroom were collected using a Burkard Personal Air Sampler and counted under light microscopy. Three-level hierarchical modeling was used to determine the complex correlation between fungal spores in classrooms and childhood asthma.

RESULTS

The survey was completed by 6,346 out of 7,154 parents (88.7%). The prevalences of physician-diagnosed asthma, current asthma, and asthma with symptoms reduced on holidays or weekends (ASROH) were 11.7%, 7.5%, and 3.1%, respectively. The geometric mean spore concentrations of total fungi, Aspergillus/Penicillium, and basidiospores were 2,181, 49, and 318 spores/m3. Aspergillus/Penicillium and basidiospores were significantly correlated with current asthma and ASROH after adjusting for personal and school factors. Of those with current asthma, 41% reported relief of symptoms during weekends.

CONCLUSIONS

Classroom Aspergillus/Penicillium and basidiospores are significantly associated with childhood asthma and ASROH. Government health policy should explore environmental interventions for the elimination of fungal spores in classrooms to reduce the prevalence of childhood asthma.

Drosophila melanogaster as a model to characterize fungal volatile organic compounds

Fungi are implicated in poor indoor air quality and may pose a potential risk factor for building/mold related illnesses. Fungi emit numerous volatile organic compounds (VOCs) as alcohols, esters, ethers, ketones, aldehydes, terpenoids, thiols, and their derivatives. The toxicity profile of these VOCs has never been explored in a model organism, which could enable the performance of high throughput toxicological assays and lead to a better understanding of the mechanism of toxicity. We have established a reductionist Drosophila melanogaster model to evaluate the toxicity of fungal VOCs. In this report, we assessed the toxicity of fungal VOCs emitted from living cultures of species in the genera, Trichoderma, Aspergillus, and Penicillium and observed a detrimental effect on larval survival. We then used chemical standards of selected fungal VOCs to assess their toxicity on larval and adult Drosophila. We compared the survival of adult flies exposed to these fungal VOCs with known industrial toxic chemicals (formaldehyde [37%], xylene, benzene, and toluene). Among the tested fungal VOC standards, the compounds with eight carbons (C8) caused greater truncation of fly lifespan than tested non-C8 fungal VOCs and industrial toxins. Our data validate the use of Drosophila melanogaster as a model with the potential to elucidate the mechanistic attributes of different toxic VOCs emitted by fungi and also to explore the potential link between reported human illnesses/symptoms and exposure to water damaged and mold contaminated buildings.

Fungal allergy in asthma-state of the art and research needs

Sensitization to fungi and long term or uncontrolled fungal infection are associated with poor control of asthma, the likelihood of more severe disease and complications such as bronchiectasis and chronic pulmonary aspergillosis. Modelling suggests that >6.5 million people have severe asthma with fungal sensitizations (SAFS), up to 50% of adult asthmatics attending secondary care have fungal sensitization, and an estimated 4.8 million adults have allergic bronchopulmonary aspergillosis (ABPA). There is much uncertainty about which fungi and fungal allergens are relevant to asthma, the natural history of sensitisation to fungi, if there is an exposure response relationship for fungal allergy, and the pathogenesis and frequency of exacerbations and complications. Genetic associations have been described but only weakly linked to phenotypes. The evidence base for most management strategies in ABPA, SAFS and related conditions is weak. Yet straightforward clinical practice guidelines for management are required. The role of environmental monitoring and optimal means of controlling disease to prevent disability and complications are not yet clear. In this paper we set out the key evidence supporting the role of fungal exposure, sensitisation and infection in asthmatics, what is understood about pathogenesis and natural history and identify the numerous areas for research studies.

Impact of a cleaners' strike on compensation claims for asthma among teachers in Ontario

BACKGROUND

A review of Workplace Safety and Insurance Board (WSIB) claims in Ontario from 1998 to 2002 showed an unusual spike in the number of claims accepted for work-exacerbated asthma (WEA) in April 2001.

OBJECTIVE

To identify the cause for the spike in the number of WSIB claims for WEA in April 2001.

METHODS

File reviews were performed to identify the occupations of workers with claims accepted for WEA in April 2001 compared with claims during March and May 2001, and during the same months in 2000 and 2002.

RESULTS

In April 2001, there were 61 accepted WEA claims; the most common occupation was 'teacher'. In contrast, among educational workers, there was only one WEA claim in the previous month and one in the following month. From March to May in the preceding and following years, there were only four and two claims, respectively. The most frequently implicated causative agents were dust and dirt exposure, which were responsible for 98% of claims; the mean (± SD) number of lost workdays was 6.5±10. The only identified environmental change associated with this spike was a cleaners' strike at all elementary and high schools in the Toronto District School Board in Ontario, which started on March 31, 2001 and ended on May 1, 2001.

CONCLUSION

[corrected] The spike in accepted WEA claims in Ontario in April 2001 was temporally associated with a strike by Toronto District School Board cleaners, suggesting acute symptomatic effects of poor workplace (school) maintenance on asthmatic employees. The WSIB database was sufficiently sensitive to capture this phenomenon.

The antifungal efficacy of nano-metals supported TiO₂ and ozone on the resistant Aspergillus niger spore

Recently, antimicrobial efficacy of nano-metals has been extensively investigated. However, most of the related studies focused on the bactericidal effectiveness. Molds, especially their spores, are more resistant than bacteria, and can build a high concentration in houses due to dampness. Therefore, a comprehensive evaluation of the antifungal effectiveness of nano-metals is necessary. In this study, the nano-metals (Ag, Cu and Ni) supported catalysts were successfully prepared by the incipient wetness impregnation method, while the titanium dioxide (Degussa (Evonik) P25) nanoparticle was served as the support. The antifungal experiments of Aspergillus niger spores were conducted on two surfaces (quartz and putty) in the darkness with and without ozone exposure, respectively. The critical Ag concentration to inhibit the germination and growth of A. niger spores of 5 wt% nano Ag catalyst was 65 mg/mL, lower than several cases in previous studies. The inactivation rate constants (k) of A. niger spores on nano-metals supported catalysts in the presence of ozone (k=0.475-0.966 h(-1)) were much higher than those in the absence of ozone (k=0.001-0.268 h(-1)). However, on the surface of TiO₂ particles, no antifungal effect was observed until 6-h exposure to ozone. Consequently, ozone has a synergetic effect on nano-metals antifungal efficacy.

Occupational exposure to aflatoxin B1: the case of poultry and swine production

Although there is an abundance of literature concerning the ingestion of food contaminated with aflatoxin B1 (AFB1), only a small number of studies explore mycotoxin exposure in occupational settings. Taking this into consideration, our study was developed with the intention of elucidating whether there is occupational exposure to AFB1 in Portuguese poultry and swine production facilities. A specific biomarker was used to assess exposure to AFB1. A total of 45 workers (34 from poultry farms; 11 from swine production facilities) participated in this study, providing blood samples. Additionally, a control group (n=30) composed of subjects without any type of contact with agricultural activity was considered. All participants signed a consent form and were provided with the study protocol. Eighteen poultry workers (58.6%) and six workers from the swine production facilities (54.5%) showed detectable levels of AFB1. In the control group, the AFB1 values were all below 1 ng/ml. No significant differences in AFB1 levels in serum between workers from poultry and swine farms were found. Poultry workers, however, showed the highest serum levels and a significant statistical difference between this group and the control group was found. Results suggest that exposure to AFB1 by inhalation occurs in both occupational settings representing an additional risk that needs to be recognised, assessed and prevented.

Home life: factors structuring the bacterial diversity found within and between homes

Most of our time is spent indoors where we are exposed to a wide array of different microorganisms living on surfaces and in the air of our homes. Despite their ubiquity and abundance, we have a limited understanding of the microbial diversity found within homes and how the composition and diversity of microbial communities change across different locations within the home. Here we examined the diversity of bacterial communities found in nine distinct locations within each of forty homes in the Raleigh-Durham area of North Carolina, USA, using high-throughput sequencing of the bacterial 16S rRNA gene. We found that each of the sampled locations harbored bacterial communities that were distinct from one another with surfaces that are regularly cleaned typically harboring lower levels of diversity than surfaces that are cleaned infrequently. These location-specific differences in bacterial communities could be directly related to usage patterns and differences in the likely sources of bacteria dispersed onto these locations. Finally, we examined whether the variability across homes in bacterial diversity could be attributed to outdoor environmental factors, indoor habitat structure, or the occupants of the home. We found that the presence of dogs had a significant effect on bacterial community composition in multiple locations within homes as the homes occupied by dogs harbored more diverse communities and higher relative abundances of dog-associated bacterial taxa. Furthermore, we found a significant correlation between the types of bacteria deposited on surfaces outside the home and those found inside the home, highlighting that microbes from outside the home can have a direct effect on the microbial communities living on surfaces within our homes. Together this work provides the first comprehensive analysis of the microbial communities found in the home and the factors that shape the structure of these communities both within and between homes.

Aerobiology and its role in the transmission of infectious diseases

Aerobiology plays a fundamental role in the transmission of infectious diseases. As infectious disease and infection control practitioners continue employing contemporary techniques (e.g., computational fluid dynamics to study particle flow, polymerase chain reaction methodologies to quantify particle concentrations in various settings, and epidemiology to track the spread of disease), the central variables affecting the airborne transmission of pathogens are becoming better known. This paper reviews many of these aerobiological variables (e.g., particle size, particle type, the duration that particles can remain airborne, the distance that particles can travel, and meteorological and environmental factors), as well as the common origins of these infectious particles. We then review several real-world settings with known difficulties controlling the airborne transmission of infectious particles (e.g., office buildings, healthcare facilities, and commercial airplanes), while detailing the respective measures each of these industries is undertaking in its effort to ameliorate the transmission of airborne infectious diseases.

Identification of aero-allergens from Rhizopus oryzae: an immunoproteomic approach

Airborne fungal spores bearing allergens are the causative agent for inducing immediate hypersensitive reaction in sensitive individuals. In this study the potential aeroallergens have been reported for the first time from Rhizopus oryzae a common airborne mold. Clinical data based on SPT was further confirmed by ELISA. IgE reactive bands were revealed by one-dimensional immunoblotting. A 44 kDa major reactive band was found in all immunoblots. For precise identification of allergens, an immuno-proteomic approach was taken with a combination of 2-Dimensional gel electrophoresis and Mass-spectrometry. 2D map of spore-mycelial protein was confronted with pooled sera and several IgE reactive spots were detected, most of which were glycoproteins and except for one, which has no antigenic determinacy after metaperiodate modification. Each of those spots was identified by MALDI-TOF-TOF. Some bioinformatic approaches were taken to predict the signal peptide and subcellular localization of each protein. Major 44 kDa allergen was identified as Aspartyl endopeptidase. Sequence information was extracted from MS/MS spectra of two tryptic peptides generated from the 44 kDa endopeptidase. Multiple alignments with other reported aspartyl protease allergens showed significant homology. Allergenicity assessment of this protein was performed in silico and identified as a potential putative allergen.