Microfungal contamination of damp buildings--examples of risk constructions and risk materials.

To elucidate problems with microfungal infestation in indoor environments, a multidisciplinary collaborative pilot study, supported by a grant from the Danish Ministry of Housing and Urban Affairs, was performed on 72 mold-infected building materials from 23 buildings. Water leakage through roofs, rising damp, and defective plumbing installations were the main reasons for water damage with subsequent infestation of molds. From a score system assessing the bioavailability of the building materials, products most vulnerable to mold attacks were water damaged, aged organic materials containing cellulose, such as wooden materials, jute, wallpaper, and cardboard. The microfungal genera most frequently encountered were Penicillium (68%), Aspergillus (56%), Chaetomium (22%), Ulocladium, (21%), Stachybotrys (19%) and Cladosporium (15%). Penicillium chrysogenum, Aspergillus versicolor, and Stachybotrys chartarum were the most frequently occurring species. Under field conditions, several trichothecenes were detected in each of three commonly used building materials, heavily contaminated with S. chartarum. Under experimental conditions, four out of five isolates of S. chartarum produced satratoxin H and G when growing on new and old, very humid gypsum boards. A. versicolor produced the carcinogenic mycotoxin sterigmatocystin and 5-methoxysterigmatocystin under the same conditions.

The indoor microfungus Trichoderma viride potentiates histamine release from human bronchoalveolar cells.

Trichoderma viride (Tv) is often found in damp and mouldy buildings where people complain of adverse health effects including mucosal/respiratory symptoms. Inhaled spores can reach the alveoli and may interact with the airway epithelium. An interaction with the mucosal mast cells was studied in cells obtained by bronchoalveolar lavage (BAL) from 18 individuals. The fungal spores were found to trigger histamine release from the BAL cells, but relatively high concentrations (0.1-2 mg/ml) were needed. A similar dose response was obtained in basophil histamine release. The Tv-induced mediator release was caused by non-immunological (non-IgE-dependent) mechanisms since the histamine release was not changed by removal of IgE from the basophils before exposure of the cells to the spores. However, in very low concentrations (0.1 ng/ml) the fungal spores were found to potentiate IgE-mediated histamine release triggered by anti-IgE antibody in suspensions of BAL cells. Potentiation was also obtained in basophil histamine release, but relatively high concentrations of Tv (10(-2) mg/ ml) were needed. Our in vitro experiments show that mucosal mast cells from the airways are highly sensitive to the potentiating effect of Tv. Although inhalation studies are needed to determine the in vivo effect of the spores, the results suggest reinforcement of mediator release to be a mechanism in the adverse health implications observed in mouldy buildings.

[Accumulation of respiratory diseases among employees at a recently established refuse sorting plant]. / Ophobning af luftvejslidelser blandt ansatte på et nyopført affaldssorteringsanlaeg.

An increasing number of plants for re-use of refuse have been constructed in Denmark in recent years. The Kaastrup Plant near Skive was opened in spring 1986. The plant accepts household rubbish and industrial refuse separately. The refuse is sorted by machine (industrial refuse is sorted partially manually) and in a large partially open machine plant, refuse is converted into fuel pellets. During a period of eight months, eight out of 15 employees developed respiratory symptoms. In seven, bronchial asthma was diagnosed and chronic bronchitis in one person. Four had initial symptoms of the organic dust toxic syndrome. After further six months, another case of occupationally-conditioned asthma occurred in the plant. Only two out of nine had previously had asthma or atopic disease. The investigation did not reveal any evidence of type-I allergy. Six out of nine had specific precipitating antibodies to refuse while all had negative RAST tests to this. In spring 1989, from six to eighteen months after the onset of the symptoms, six had still dyspnoea on exertion and three had positive histamine-provocation tests and seven out of nine had left the plant. Occupational medical measurements revealed dust concentrations of 8.1 mg/cubic millimeter in September 1986 and total germs of up to 3 x 10(9) cfu/cubic meter. Construction of the plant involved considerable contact with the refuse on account of the cleansing processes and open systems and it was reconstructed in the course of 1987/1988 so that the hygienic conditions are now acceptable.(ABSTRACT TRUNCATED AT 250 WORDS)

Double blind placebo controlled exposure to molds: exposure system and clinical results.

UNLABELLED: The objective was to develop an experimental setup for human exposure to mold spores, and to study the clinical effect of this exposure in sensitive subjects who had previously experienced potentially building-related symptoms (BRS) at work. From three water-damaged schools eight employees with a positive histamine release test to Penicillium chrysogenum were exposed double- blinded to either placebo, approximately 600,000 spores/m3 air of P. chrysogenum or approximately 350,000 spores/m3 of Trichoderma harzianum for 6 min on three separate days. A statistically significant rise in symptoms from mucous membranes appeared from the 9-graded symptom scale after exposure to T. harzianum or placebo. Dichotomizing the data, whether the participants experienced at least a two-step rise on the symptom scale or not, gave borderline increase in mucous membrane symptoms after exposure to P. chrysogenum. In conclusion this is, to our knowledge, the first study to successfully conduct a human exposure to a highly controlled dose of fungal material aerosolized directly from wet building materials. This short-term exposure to high concentrations of two different molds induced no more reactions than exposure to placebo in eight sensitive school employees. However, a statistical type II error cannot be excluded because of the small sample size. PRACTICAL IMPLICATIONS: In this double blind, placebo controlled study of mold exposure changes in symptoms, objective measurements and blood samples were small and mostly non-significant, and at the same level as after placebo exposure. The developed exposure system based on the Particle-Field and Laboratory Emission Cell (P-FLEC) makes it possible to deliver a precise and highly controlled dose of mold spores from water-damaged building materials, imitating realistic field exposure conditions. The present experiment is too small to rule out an effect of mold exposure; long-term experimental exposure studies on larger number of subjects are needed.

Microbiology on indoor air '99--what is new and interesting? An overview of selected papers presented in Edinburgh, August, 1999.

A multidisciplinary approach to microbiological implications of indoor air is fruitful for research as well as management of health and building problems. The Finnish and the Danish mold programs are examples of such productive collaborative studies. Dust samples taken from classrooms in schools where occupants complain of building-related symptoms (BRS) demonstrated an inflammatory potential in vitro, measured as a release of cytokine interleukin (IL)-8. An increase of the metabolite NO and liberation of tumor necrosis factor (TNF)-alpha and other cytokines during exposure were obtained in vivo, was presented based on these programs and on epidemiological studies on residential fungal contamination and health conducted in Canada and The Netherlands. New methods for assessing fungal exposure are PCA analysis for the toxigenic mold Stachybotrys chartarum and EPS-Asp/Pen for detecting of Aspergillus and Penicillium in dust. Based on a limited data set it is shown that emission rates of fungal spores are inversely proportional to relative humidity (RH), directly related to flow rate and to surface loading. Poor maintenance, risk constructions and risk materials are described in several studies as the main causes of water damage in buildings.

Identification and prevalence of culturable mesophilic microfungi in house dust from 100 Danish homes. Comparison between airborne and dust-bound fungi.

In order to encircle possible allergen sources, fungi from house dust were cultivated and identified. Dust from vacuum cleaners was inoculated on Petri dishes containing V-8 agar with addition of penicillin and streptomycin to eliminate the bacterial flora. The number of genera identified were for the most part consistent with the genera trapped from the air. However, presumably owing to their dispersal biology it was demonstrated that members of Mucorales were much more frequently represented in the samples obtained by this method compared with gravimetric and volumetric measurements. The method is recommended as a simple way to demonstrate and identify the mould contents in house dust and as a tool for the identification of some of the real allergenic sources in house dust.

Extrinsic allergic alveolitis after exposure to the yeast Rhodotorula rubra.

A case of extrinsic allergic alveolitis following exposure to the red yeast Rhodotorula rubra is reported--to our knowledge, for the first time. Extensive growth of the yeast in the patient's environment was demonstrated, explaining an elevated titer of Rhodotorula-specific precipitating antibodies in his serum. A bronchial provocation test confirmed the diagnosis.

Aerobiology of schools and public institutions--part of a study.

The influence of the indoor climate in relation to the health of persons has mainly been connected with the physico-chemical properties of the environment. Complaints from patients concerning eye, nose and throat problems, hoarseness, headache and fatigue are common, especially in schools and other public institutions with heavy traffic and badly cleaned or water damaged wall-to-wall carpets. The significance of specific allergenic components in dust such as mites, mould, animal dander and pollen is well-known. However, the influence of a dirt-factor or a moisture-factor in the carpets or from ventilation systems leading to accumulation, liberation and inhalation of dust and micro-organisms, on allergic and non-allergic persons has, until recently, been neglected. To obtain knowledge on this influence, a systematical registration of the biological factors based on consecutive investigation has started. Results from registration of airborne micro-organisms show a tendency towards a larger amount of micro-organisms measured 1 m above carpets than above bare floors.

Demonstration isolation and identification of culturable microfungi and bacteria in horse hair and dandruff. Immunochemical comparison with allergic components.

Horse hiar and dandruff have been investigated for their content of microfungi and bacteria. Inoculation and incubation on V-8 agar containing penicillin and streptomycin, with subsequent colony counting and identification, revealed more than nine and five different genera of microfungi and bacteria respectively, in horse hair and dandruff. Isolation and cultivation of the quantitatively dominating species, and preparation of an extract of these were performed, followed by immunochemical comparison with extract of the horse hair and dandruff using crossed-line immuno-electrophoresis. As no immunochemical identity was demonstrated it was concluded that the identified microorganisms might serve as a guideline to suspected sensitizing substances when patients with a typical case history of horse allergy do not react to extracts of horse hair and dandruff.

Cladosporium herbarum extract characterized by means of quantitative immunoelectrophoretic methods with special attention to immediate type allergy.

Freeze-dried extract of Cladosporium herbarum Link ex Fr. was obtained by growing, harvesting, extracting, centrifuging, dialysing and freeze-drying. Quantitative immunoelectrophoresis using rabbit antibodies revealed the extraction procedure to be reproducible and the extract to be composed of 57 antigens, none of which originated from the substrate used in the growth. The molecular weight distribution and the approximate molecular weight of some antigens of C. herbarum were obtained using gel filtration. The pI distribution and the approximate pIs of a few distinct antigens of C. herbarum were obtained by isoelectric focusing. Preliminary identification of 4 allergens from C. herbarum was performed by means of CRIE (crossed radioimmunoelectrophoresis).

Demonstration of microorganisms and dust in schools and offices. An observational study of non-industrial buildings.

"The sick-building syndrome" (WHO) is reported with increasing intensity in non-industrial places of work, such as schools, kindergartens, and offices, all of which have a heavy load of traffic (people). The construction of these buildings (e.g. flat roofs) often leads to water damage with subsequent microbial growth. Further, reduced cleaning budgets in connection with the wide use of needle-felt carpets, as well as ventilation systems not regularly maintained, will lead to pollution by dust and microorganisms. A systematic registration of dust and microbial parameters has been carried out since 1980 in buildings with indoor climate complaints, in order to elucidate the possible influence of these factors.

Respiratory disorders and atopy in cotton, wool, and other textile mill workers in Denmark.

A cross-sectional study of respiratory disorders and atopy in Danish textile industry workers was conducted to survey respiratory symptoms throughout the textile industry, to estimate the association of these disorders with atopy, and to study dose-response relationships within the cotton industry. Workers at cotton mills, a wool mill, and a man-made fiber (MMF) mill were examined. Four hundred nine (90%) of the 445 workers participated in this survey, i.e., 253, 62, and 94 workers at the cotton mills, the wool mill, and the MMF mill, respectively. An interview designed to assess the prevalence of common respiratory and allergic symptoms was given to all workers willing to participate, and blood samples were drawn. Lung function measurements determined a baseline FEV1, FVC and the change in FEV1 and FVC during work hours on a Monday. The working environment was examined for dust, bacteria, endotoxins, and molds, and the exposure was estimated for each participant. The mean personal samples of airborne respirable dust and respirable endotoxin were highest in the cotton industry, i.e., 0.17-0.50 mg/m3 and 9.0-126 ng/m3 respectively, whereas mold spores were found in the highest concentrations in the wool mill: 280-791 colony-forming units (cfu)/m3. Only small concentrations of microorganisms were found in the MMF mill. The mean change in FEV1% and FVC% was greatest among atopic individuals in both cotton and wool industry and other textile industries although the differences were not significant. FEV1% and FVC% in the cotton workers were significantly associated with the cumulative exposure to respirable endotoxin. Byssinosis was diagnosed only in the cotton industry. We found a dose-response relationship between endotoxin exposure and byssinosis, and a significant association between A-1-A serum concentrations less than or equal to 35 mumol/liter and byssinosis, a finding we are further evaluating in subsequent studies.

Extreme fatigue and malaise--a syndrome caused by badly cleaned wall-to-wall carpets?

Complaints connected with the indoor climate are often vague and a cause-effect relationship is difficult to demonstrate. The present paper describes two patients suffering from symptoms in the form of extreme fatigue and malaise. The patients connected their problems to the poorly cleaned working place. We found the working place to be covered with badly cleaned wall-to-wall carpet. Examination of 12 employees showed five to have symptoms related to the working place. Four of the five had precipitating antibodies against extracts of dust collected from the carpets and two of the five had a positive prick test to the same extract. After removal of the carpets all symptoms disappeared. We conclude that vague symptoms related to the indoor climate may be induced by accumulation of organic dust.

Precipitating antibodies against Micropolyspora phaeni in sera from mushroom workers.

A new method for determining precipitating antibodies in allergic alveolitis is presented. The principle used is immunoelectrophoresis, either as a counterelectrophoresis or as a crossed immunoelectrophoresis with intermediate gel. Twenty-two mushroom workers without anamnestic signs of allergic alveolitis and 15 control persons were investigated. Twelve mushroom workers (55%) had precipitating antibodies as determined by crossed immunoelectrophoresis, and nine of these persons had antibodies demonstrated with counterelectrophoresis. Thus, the sensitivity seems greater in the crossed immunoelectrophoresis, but we find that the simpler counterelectrophoresis is an excellent screening procedure in patients suspected of allergic alveolitis. In the controls only one person had precipitating antibodies, though the antigen tested for Micropolyspora phaeni exists ubiquitously. It seems probable from this study that the antigenic load is important, although it is remarkable that no mushroom worker with precipitating antibodies against M. phaeni had ever experienced symptoms compatible with allergic alveolitis.

Indoor viable dust-bound microfungi in relation to residential characteristics, living habits, and symptoms in atopic and control children.

Floor dust was collected in the wintertime from the homes of 61 children sensitized to house dust mites, 57 children with sensitization to other aeroallergens, and 57 nonatopic control children. The dust was cultivated and microfungal growth was identified microscopically. Indoor humidity was measured, and condensation on windowpanes was registered during 1 winter week. Housing and sociodemographic and symptom data were obtained by a questionnaire. Penicillium, Alternaria, and Cladosporium were the three most common microfungi. The mean total number of colony-forming units per 30 mg of dust was significantly lower in the homes of the two atopic groups than in homes of the control group, which may be a result of allergen-sanitation measures. High colony-forming unit counts appeared to be related to damp housing. Weak associations were found between the occurrence of viable fungi in dust and allergic symptoms among the house dust mite-sensitized children. However, no consistent association between viable mold growth and sensitization to molds was observed. The health implications of indoor fungal exposure still remain unclear.