High Spore Concentrations Research Articles

Importance of mold allergy in asthma

Fungal exposure is hypothesized (controversially) to contribute to asthma development and to trigger symptoms in patients with asthma. The ubiquity of environmental fungal exposure makes a careful review of evidence essential. Evidence that exposure to high concentrations of fungal spores, antigens, or metabolites is associated with asthma development is limited. However, because mechanisms of asthma genesis are poorly understood, so too are the mechanisms of this potential association. This association is not proof of causality. Stronger evidence supports the hypothesis that fungal exposure triggers symptoms in asthmatic individuals. Proposed mechanisms have been tested and correlations between exposure and symptoms demonstrated. Though some correlations remain speculative, controlled studies could test such hypotheses. Because asthma is common and fungal exposure is ubiquitous, it is surprising that asthmatics don't have more symptoms when exposed to fungi. Fortunately, symptoms are dose dependent, creating an opportunity to develop clinically effective interventions. Given the right guidance, even patients with severe asthma can create healthy indoor environments.

Bacillus cereus Spores During Housing of Dairy Cows: Factors Affecting Contamination of Raw Milk

The contamination of raw milk with Bacillus cereus spores was studied during the indoor confinement of dairy cattle. The occurrence of spores in fresh and used bedding material, air samples, feed, feces, and the rinse water from milking equipment was compared with the spore level in bulk tank milk on 2 farms, one of which had 2 different housing systems. A less extensive study was carried out on an additional 5 farms. High spore concentrations of >100 spores/L in the raw milk were found on 4 of the farms. The number of spores found in the feed, feces, and air was too small to be of importance for milk contamination. Elevated spore contents in the rinse water from the milking equipment (up to 322 spores/L) were observed and large numbers of spores were found in the used bedding material, especially in free stalls with >5cm deep sawdust beds. At most, 87,000 spores/g were found in used sawdust bedding. A positive correlation was found between the spore content in used bedding material and milk (r=0.72). Comparison of the genetic fingerprints obtained by the random amplified polymorphic DNA PCR of isolates of B. cereus from the different sources indicated that used bedding material was the major source of contamination. A separate feeding experiment in which cows were experimentally fed B. cereus spores showed a positive relationship between the number of spores in the feed and feces and in the feces and milk (r=0.78). The results showed that contaminated feed could be a significant source of spore contamination of raw milk if the number of spores excreted in the feces exceeded 100,000/g.

Concentrations of Butyric Acid Bacteria Spores in Silage and Relationships with Aerobic Deterioration

Germination and growth of spores of butyric acid bacteria (BAB) may cause severe defects in semihard cheeses. Silage is the main source of BAB spores in cheese milk. The objectives of the study were to determine the significance of grass silages and corn silages as sources of BAB spores and to investigate the relationships between high concentrations of BAB spores in corn silage and aerobic deterioration. In the first survey, samples were taken from various locations in silos containing grass and corn silages and from mixed silages in the ration offered to the cows on 21 farms. We demonstrated that the quantity of BAB spores consumed by cows was determined by a small fraction of silage with a high concentration of spores (above 5 log10BAB/g). High concentrations were most often found in corn silage within areas with visible molds (69% of the samples). Areas with visible molds in grass silage and surface layers of corn silage contained, respectively, 21 and 19% of the cases of concentrations above 5 log10BAB spores/g. Based on these results, we concluded that currently in the Netherlands, corn silage is a more important source of BAB than is grass silage. In a second survey, 8 corn silages were divided into 16 sections and each section was studied in detail. High concentrations of BAB spores were found in only the top 50cm of these 8 silages. Elevated concentrations of BAB spores were associated with different signs of aerobic deterioration. In 13% of the sections in corn silage with more than 5 log10yeasts and molds/g, more than 5 log10BAB spores/g were found. Sections with a temperature of more than 5°C above ambient temperature contained, in 21% of the cases, more than 5 log10BAB spores/g. Concentrations above 5 log10BAB spores/g were measured in 50% of the sections with a pH above 4.4. All sections with a pH above 4.4 also showed a temperature that was more than 5°C above ambient temperature and a concentration of yeasts and molds above 5 log10cfu/g. Based on these results, we postulated that high concentrations of BAB spores in corn silage are the result of oxygen penetration into the silage, resulting in aerobic deterioration and the formation of anaerobic niches with an increased pH just below the surface. Growth of BAB in these anaerobic niches with an increased pH caused the locally high concentrations of BAB in corn silage.

Demolition of High-Rise Public Housing Increases Particulate Matter Air Pollution in Communities of High-Risk Asthmatics

Public housing developments across the United States are being demolished, potentially increasing local concentrations of particulate matter (PM) in communities with high burdens of severe asthma. Little is known about the impact of demolition on local air quality. At three public housing developments in Chicago, IL, PM with an aerodynamic diameter <10 μm (PM10) and <2.5 μm were measured before and during high-rise demolition. Additionally, size-selective sampling and real-time monitoring were concurrently performed upwind and downwind of one demolition site. The concentration of particulates attributable to demolition was estimated after accounting for background urban air pollution. Particle microscopy was performed on a small number of samples. Substantial increases of PM10 occurred during demolition, with the magnitude of that increase varying based on sampler distance, wind direction, and averaging time. During structural demolition, local concentrations of PM10 42 m downwind of a demolition site increased 4- to 9-fold above upwind concentrations (6-hr averaging time). After adjusting for background PM10, the presence of dusty conditions was associated with a 74% increase in PM10 100 m downwind of demolition sites (24-hr averaging times). During structural demolition, short-term peaks in real-time PM10 (30-sec averaging time) occasionally exceeded 500 μg/m3. The median particle size downwind of a demolition site (17.3 μm) was significantly larger than background (3 μm). Specific activities are associated with real-time particulate measures. Microscopy did not identify asbestos or high concentrations of mold spores. In conclusion, individuals living near sites of public housing demolition are at risk for exposure to high particulate concentrations. This increase is characterized by relatively large particles and high short-term peaks in PM concentration.

Seasonal variation of mono- and sesquiterpene emission rates of Scots pine

Abstract. The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception of weekends. Emissions were measured from two branches; one of them was debudded in May (branch A), while the other was allowed to grow new needles (branch B). The monoterpene emission pattern remained almost constant throughout the measurement period, Δ3-carene being the dominant monoterpene (50-70% of the VOC emission). The standard monoterpene emission potential (30°C) was highest during early summer in June (the average of the two branches 1.35 µg g-1h-1) and lowest during early autumn in September (the average of the two branches 0.20 µg g-1h-1. The monoterpene emission potential of branch A remained low also during October, whereas the emission potential of branch B was very high in October. The sesquiterpenes were mainly emitted during mid summer, the dominant sesquiterpene being β-caryophyllene. Branch A had a higher sesquiterpene emission potential than branch B and the emission maximum occurred concomitant with the high concentration of airborne pathogen spores suggesting a potential defensive role of the sesquiterpene emissions. The sesquiterpene emissions were well correlated with linalool and 1,8-cineol emissions, but not with monoterpenes. Sesquiterpene and 1,8-cineol emissions were equally well described by the temperature dependent and the temperature and light dependent algorithms. This is due to the saturation of the light algorithm as the measurements were always conducted during high light conditions.

A better anthrax screener?

A newly marketed anthrax detector that originated in the US space program promises to reduce the detection time of the system currently used by the US Postal Service. Devised by the CA-based Universal Detection Technology Inc., BSM-2000 continuously samples surrounding air for high concentrations of bacterial spores and triggers an alarm only on registering a bacterial spore count of 50 or more per liter, on the assumption that a bioterrorist attack will release spores in much greater quantities than normally found. It features a fiber optic system that delivers a microwave beam that heats the outer shell of any bacterial spore and causes it to explode and release a particular chemical, dipicolinic acid (DPA), which is characteristic of all bacteria, including anthrax. The liberated DPA adheres to a tape strip within the device, and if enough collects on the strip, ultraviolet light causes a bright green luminescence to appear. BSM-2000 requires little maintenance and does not require cartridge replacement.

Contribution of leaf surface fungi to the air spora

High concentrations of airborne fungal spores frequently occur from spring through fall in temperate areas of the world. Although it is generally assumed that fungi on leaf surfaces are contributors to the air spora, little data are available comparing the types of fungi found on leaf surfaces with those in the atmosphere. Air sampling was carried out with a Burkard Spore Trap located on the roof of a building on the University of Tulsa campus using standard methods. Leaf samples were aseptically collected from Ulmus americana and Quercus palustris trees on campus, placed in sterile plastic bags, and brought to the lab. For each leaf, 4 cm2 areas of both upper and lower leaf surfaces were swabbed and plated on malt extract agar with streptomycin. Cultures were incubated at room temperature for 5–7 days and then examined microscopically. Results were expressed as colony forming units (CFU)/cm2. Twenty-one fungal taxa were identified from the air samples. The most abundant taxa were Cladosporium, ascospores, basidiospores, and Alternaria; together these four spore types comprised over 90% of the yearly total. Yeasts were the most abundant fungi isolated from both leaf types. Among the mycelial fungi were Phoma species, followed by Cladosporium and Alternaria. Overall twenty genera of filamentous fungi were identified. Yeasts and Phoma are normally splash dispersed and were not identified in the Burkard air samples. However, 10 taxa isolated from leaf surfaces were registered in air samples. Crude estimates of the leaf surface area of each tree suggest that the total fungal load was approximately 5.04×108 CFU for Ulmus and 2.71×108 CFU for Quercus. Of these levels, 19% were from fungi also detected in air samples. The data suggest that some leaf-surface fungi are major contributors to the air spora.

Relationship between indoor and outdoor bioaerosols collected with a button inhalable aerosol sampler in urban homes

This field study investigated the relationship between indoor and outdoor concentrations of airborne actinomycetes, fungal spores, and pollen. Air samples were collected for 24 h with a button inhalable aerosol sampler inside and outside of six single-family homes located in the Cincinnati area (overall, 15 pairs of samples were taken in each home). The measurements were conducted during three seasons - spring and fall 2004, and winter 2005. The concentration of culturable actinomycetes was mostly below the detection limit. The median indoor/outdoor ratio (I/O) for actinomycetes was the highest: 2.857. The indoor of fungal and pollen concentrations followed the outdoor concentrations while indoor levels were mostly lower than the outdoor ones. The I/O ratio of total fungal spores (median=0.345) in six homes was greater than that of pollen grains (median=0.025). The low I/O ratios obtained for pollen during the peak ambient pollination season (spring) suggest that only a small fraction penetrated from outdoor to indoor environment. This is attributed to the larger size of pollen grains. Higher indoor concentration levels and variability in the I/O ratio observed for airborne fungi may be associated with indoor sources and/or higher outdoor-to-indoor penetration of fungal spores compared to pollen grains. Practical Implication This study addresses the relationship between indoor and outdoor concentrations of three different types of bio-aerosols, namely actinomycetes, fungal spores, and pollen grains. The results show that actinomycetes are rare in indoor and outdoor air in Midwest, USA. Exposure to pollen occurs mainly in the outdoor air even during peak pollen season. Unexpectedly high fungal spore concentrations were measured outdoors during winter. The presented pilot database on the inhalable levels of indoor and outdoor bio-aerosols can help apportion and better characterize the inhalation exposure to these bio-aerosols. Furthermore, the data can be incorporated into existing models to quantify the penetration of biological particles into indoor environments from outdoors.

Detection and quantification of Cladosporium in aerosols by real-time PCR

Cladosporium is one of the most common airborne molds found in indoor and outdoor environments. Cladosporium spores are important aeroallergens, and prolonged exposure to elevated spore concentrations can provoke chronic allergy and asthma. To accurately quantify the levels of Cladosporium in indoor and outdoor environments, two real-time PCR systems were developed in this study. The two real-time PCR systems are highly specific and sensitive for Cladosporium detection even in a high background of other fungal DNAs. These methods were employed to quantify Cladosporium in aerosols of five different indoor environments. The investigation revealed a high spore concentration of Cladosporium (10(7) m(-3)) in a cow barn that accounted for 28-44% of the airborne fungal propagules. In a countryside house that uses firewood for heating and in a paper and pulp factory, Cladosporium was detected at 10(4) spores m(-3), which accounted for 2-6% of the fungal propagules in the aerosols. The concentrations of Cladosporium in these three indoor environments far exceeded the medical borderline level (3000 spores m(-3)). In a power station and a fruit and vegetable storage, Cladosporium was found to be a minor component in the aerosols, accounted for 0.01-0.1% of the total fungal propagules. These results showed that monitoring Cladosporium in indoor environments is more important than in outdoor environments from the public health point of view. Cladosporium may not be the dominant fungi in some indoor environments, but its concentration could still be exceeding the threshold value for clinical significance. The methods developed in this study could facilitate accurate detection and quantification of Cladosporium for public health related risk assessment.

Assessment of Fungal Growth on Sodium Polyborate-Treated Cellulose Insulation

Cellulose insulation has rapidly gained a large market share among general contractors and homeowners. Recent interest regarding health effects of high concentrations of fungi within indoor environments (building-related illnesses or sick building syndrome) has promoted concern about susceptibility of building materials, including wood products (in general) and cellulose insulation (specifically), to fungal attack. This study reports an assessment of fungal growth on cellulose insulation made from recycled paper and treated with varying concentrations of sodium polyborate within half-scale wall units exposed to variable and high ambient temperatures and relative humidities throughout the summer. Boron-treated and untreated (control) cellulose insulation within the wall units were challenged with a suspension containing high concentrations of spores of five fungal species commonly found in indoor environments. Our results suggest that cellulose insulation treated with sodium polyborate (a) precludes the growth of the five common fungal species; (b) harbors fewer fungal species before and after being challenged with the fungal spore suspension; and (c) is likely having a cytotoxic or sporocidal effect on many, if not all, fungal species. These results suggest that cellulose insulation treated with sodium polyborate, when properly applied and installed, precludes fungal growth for at least 124 days at high temperatures and relative humidities.

Cerebral zygomycosis

Fifty-six patients with cerebral zygomycosis (mucormycosis) were seen during the period 1971-2001 in two tertiary care hospitals located in south India with tropical climate and catering to neurological diseases. Forty-four patients had rhinocerebral and twelve patients had isolated central nervous system (CNS) zygomycosis. Of these, ten were culture proven (Rhizopus oryzae in eight and Mucor in two); 30 were diagnosed as probable and 16 were diagnosed possible; mixed infections were seen in three patients. Diabetes mellitus was the predisposing condition in a majority (31/44) of patients with the rhinocerebral form of zygomycosis. The tissue obtained at biopsy/autopsy in either form showed necrotic/infarcted tissue with neutrophilic infiltration with broad non-septate hyphae showing irregular branching. The outcome was poor despite surgical excision and antifungal therapy. The high concentration of spores in a mouldy environment, the bird population and improper disposal of hospital waste may facilitate healthy hosts presenting with primary CNS disease.

Variation assessment of airborne Alternaria and Cladosporium spores at different bioclimatical conditions

The study of mould spores is of major importance as many fungi can cause considerable economic losses worldwide acting as plant pathogens or triggering respiratory diseases and allergenic processes in humans. Knowledge of spore production relationships to different altitudes or weather patterns can be applied in a more efficient and reliable use of pesticides or improving diagnosis and treatment of respiratory allergic diseases. In this way monitoring of Cladosporium cladosporioides, C. herbarum and Alternaria spp. airborne spores during 2002 was carried out by means of three LANZONI VPPS 2000 pollen traps located in areas of north-west Spain at various altitudes and with various weather patterns. High spore counts were recorded in the late summer and early autumn, with a fairly similar hourly spore-count pattern, increasing the concentrations in the late evening (7-10 p.m.). High spore concentrations were detected in inland rural areas in front of coastal ones. As the continentality index increased, C. cladosporioides spore concentrations rose and Alternaria declined. C. herbarum concentrations increased with increasing height above sea level. The weather factor displaying the strongest positive correlation with mean daily spore counts was temperature. The optimal conditions for high airborne spore concentrations were recorded at temperatures ranging from 23-29 degrees C and RH values of around 80%, followed rapidly by rainfall in Vigo and Ourense and preceded by heavy rain two days prior to recording peak values in Trives.

Production of Bacillus thuringiensis‐based biopesticides in batch and fed batch cultures using wastewater sludge as a raw material

AbstractBacillus thuringiensis subsp kurstaki was grown in batch and fed batch cultures using wastewater sludge as a raw material. A simple fed batch strategy based on dissolved oxygen measurement during the fermentation cycle was developed in this work. It was established that while shifting the process strategy from batch to fed batch, the maximum spore concentration was increased from 5.62 × 108 to 8.6 × 108 colony forming units per cm3 and resulted in an increase of entomocidal activity from 13 × 109 to 18 × 109 spruce budworm potency units per dm3. Higher entomotoxicity was recorded at low spore concentration using wastewater sludge as a raw material whereas low entomotoxicity was reported at high spore concentration in synthetic medium. Copyright © 2005 Society of Chemical Industry

Mold

Many libraries have experienced mold outbreaks. A common response by either the library's or the institution's administration has been to organize a simple clean up. Utilizing library or facilities staff, the mold is wiped off the books and nearby surfaces, shelving and flooring, are washed with a disinfectant solution. Frequently, this level of containment, along with efforts taken to prevent a re-occurrence, is viewed as a time-consuming and costly nuisance that challenges limited resources. However, we are just beginning to learn enough about the health implications of mold so that additional measures must be considered to sufficiently protect the health of library users and staff. As with many pollutants, a high concentration of mold spores in the environment is increasingly believed to be a biohazard for humans, one that cannot be seen or even smelled. Library staff must become more knowledgeable in treating an outbreak of mold so they may educate and advocate for a more protective approach to containment. This shields not only local users and collections but lending libraries as well since they may become the temporary custodians of affected materials. Institutions should consider the moral obligation to protect the health of library users and staff as well as the potential for costly medical liability litigation. This article seeks to balance the traditional object-centered approach to mold that focuses on library collections and facilities with one that addresses potential health issues as well. This method is more time-consuming and includes the involvement of multiple stakeholders who often have different cost/benefit perspectives of the issues involved. It therefore recognizes that, in the end, resource limitations will almost always drive decision-making.

Airborne fungi isolated from Fortaleza city, State of Ceará, Brazil.

Airbone fungi are considered important causes of allergic rhinitis and allergic asthma. The knowledge of these fungi in a city or region is important for the ecological diagnosis and specific treatment of allergic manifestations induced by inhalation of fungal allergens. The airborne fungi of Fortaleza, State of Ceará, Brazil, were studied during a one year period. Five hundred and twenty Petri dishes with Sabouraud dextrose agar medium were exposed at ten different locations in the city. The dishes exposed yielded one thousand and five hundred and twenty one colonies of twenty four genera. The most predominants were: Aspergillus (44.7%), Penicillium (13.3%), Curvularia (9.8%), Cladosporium (6.8%), Mycelia sterilia (6.0%), Fusarium (3.5%), Rhizopus (3.1%), Drechslera (2.6%), Alternaria (2.4%) and Absidia (2.2%). The results shown that Aspergillus, Penicillium, Mycelia sterilia, Fusarium and Alternaria were found during all months in the year. Absidia was more frequent during the dry season. Anemophilous fungi and the high concentration of spores in the air are important because may result in an increased number of people with allergic respiratory disease.

Risk from inhaled mycotoxins in indoor office and residential environments.

Mycotoxins are known to produce veterinary and human diseases when consumed with contaminated foods. Mycotoxins have also been proposed to cause adverse human health effects after inhalation exposure to mold in indoor residential, school, and office environments. Epidemiologic evidence has been inadequate to establish a causal relationship between indoor mold and nonallergic, toxigenic health effects. In this article, the authors model a maximum possible dose of mycotoxins that could be inhaled in 24 h of continuous exposure to a high concentration of mold spores containing the maximum reported concentration of aflatoxins B1 and B2, satratoxins G and H, fumitremorgens B and C, verruculogen, and trichoverrols A and B. These calculated doses are compared to effects data for the same mycotoxins. None of the maximum doses modeled were sufficiently high to cause any adverse effect. The model illustrates the inefficiency of delivery of mycotoxins via inhalation of mold spores, and suggests that the lack of association between mold exposure and mycotoxicoses in indoor environments is due to a requirement for extremely high airborne spore levels and extended periods of exposure to elicit a response. This model is further evidence that human mycotoxicoses are implausible following inhalation exposure to mycotoxins in mold-contaminated home, school, or office environments.

Conidial dispersal by Alternaria brassicicola on Chinese cabbage (Brassica pekinensis) in the field and under simulated conditions

This study investigated conidial dispersal in the field, and effects of simulated wind and rain on the dispersal of A. brassicicola on Chinese cabbage (Brassica pekinensis). Spores were sampled using a Burkard volumetric spore sampler and rotorod samplers in a Chinese cabbage crop. Disease incidence in the field was well fitted by a Gompertz curve with an adjusted r2 of &gt;0·99. Conidia of A. brassicicola were trapped in the field throughout the growing season. Peaks of high spore concentrations were usually associated with dry days, shortly after rain, high temperature or high wind speed. Diurnal periodicity of spore dispersal showed a peak of conidia trapped around 10·00 h. The number of conidia trapped at a height of 25 cm above ground level was greater than that at 50, 75 and 100 cm. Conidial dispersal was also studied under simulated conditions in a wind tunnel and a rain simulator. Generalized linear models were used to model these data. The number of conidia caught increased significantly at higher wind speeds and at higher rain intensities. Under simulated wind conditions, the number of conidia dispersed from source plants with wet leaves was only 22% of that for plants with dry leaves. Linear relationships were found between the number of conidia caught and the degree of infection of trap plants.

Farmers' Exposure to Airborne Microorganisms in Composting Swine Confinement Buildings

Farmers' exposure to airborne microorganisms was studied in 12 composting swine confinement buildings and in 7 buildings with traditional slatted-floor pit systems. Airborne cultivable mesophilic, xerophilic, and thermotolerant fungi, mesophilic bacteria, and thermophilic actinobacteria were determined with a six-stage impactor. Furthermore, the total concentrations of microorganisms were determined with filter sampling and direct count using a microscope. In swine confinement buildings where the composting system was functioning properly, the concentrations of microorganisms were 10–1000 times higher than in traditional swine buildings. High concentrations of thermotolerant fungi and thermophilic actinobacteria (up to 105 CFU/m3), which have been considered to be the main causative agents of farmer's lung, were found in the composting swine confinement buildings that were studied. The conclusion was reached that farmers are exposed to high concentrations of fungal and actinobacterial spores also in swine...

The impact of nutrition on spore yields for various fungal entomopathogens in liquid culture

Spore yields were measured for various fungal entomopathogens grown in six nutritionally different liquid media with low and high carbon concentrations (8 and 36 g l−1, respectively) at carbon-to-nitrogen (C:N) ratios of 10:1, 30:1 and 50:1. Six fungi were tested: two Beauveria bassiana strains, three Paecilomyces fumosoroseus strains and one Metarhizium anisopliae strain. Spore yields were examined after 2, 4 or 7 days growth. In general, highest spore yields were obtained in media containing 36 g/l and a C:N ratio of 10:1. After 4 days growth, highest spore yields were measured in the three Paecilomyces isolates (6.9–9.7 × 108 spores ml−1). Spore production by the B. bassiana isolates was variable with one isolate producing high spore yields (12.2 × 108 spores ml−1) after 7 days growth. The M. anisopliae isolate produced low spore concentrations under all conditions tested. Using a commercial production protocol, a comparison of spore yields for the coffee berry borer P. fumosoroseus and a commercial B. bassiana isolate showed that highest spore concentrations (7.2 × 108 spores ml−1) were obtained with the P. fumosoroseus isolate 2-days post-inoculation. The ability of the P. fumosoroseus strain isolated from the coffee berry borer to rapidly produce high concentrations of spores prompted further testing to determine the desiccation tolerance of these spores. Desiccation studies showed that ca. 80% of the liquid culture produced P. fumosoroseus spores survived the air-drying process. The virulence of freshly produced, air-dried and freeze-dried coffee berry borer P. fumosoroseus blastospores preparations were tested against silverleaf whiteflies (Bemisia argentifolii). While all preparations infected and killed B. argentifolii, fresh and air-dried preparations were significantly more effective. These results suggest that screening potential fungal biopesticides for amenability to liquid culture spore production can aid in the identification of commercially viable isolates. In this study, P. fumosoroseus was shown to possess the production and stabilization attributes required for commercial development.

Farmers' exposure to airborne microorganisms in composting swine confinement buildings.

Farmers' exposure to airborne microorganisms was studied in 12 composting swine confinement buildings and in 7 buildings with traditional slatted-floor pit systems. Airborne cultivable mesophilic, xerophilic, and thermotolerant fungi, mesophilic bacteria, and thermophilic actinobacteria were determined with a six-stage impactor. Furthermore, the total concentrations of microorganisms were determined with filter sampling and direct count using a microscope. In swine confinement buildings where the composting system was functioning properly, the concentrations of microorganisms were 10-1000 times higher than in traditional swine buildings. High concentrations of thermotolerant fungi and thermophilic actinobacteria (up to 10(5) CFU/m(3)), which have been considered to be the main causative agents of farmer's lung, were found in the composting swine confinement buildings that were studied. The conclusion was reached that farmers are exposed to high concentrations of fungal and actinobacterial spores also in swineries, at least in composting confinement buildings. Therefore, personal protection is strongly recommended in composting swineries, especially during the turning of the compost bed.