Fungal Spore Levels Research Articles

Long-term use of high-efficiency vacuum cleaners and residential airborne fungal-spore exposure

Exposure to fungal allergens is an important contributor to allergic respiratory disease, but information on the efficacy of residential fungal allergen-avoidance in allergic-disease management is lacking. Using vacuum cleaners with high-efficiency exhaust filtration is one method recommended for reducing residential allergen exposure levels, but their use to reduce fungal-spore exposure levels has not been evaluated. To evaluate the effectiveness of high-efficiency vacuuming to control airborne fungal-spore levels, fungal bioaerosols were repeatedly assessed over the course of 10 months in homes randomly assigned to groups using either conventionally filtered (control) or high-efficiency-filtered vacuum cleaners for routine vacuum cleaning. Air samples were analyzed for three fungal-spore categories representing taxa with predominantly outdoor sources and one representing taxa that commonly have indoor sources. In a two-way analysis of variance, sampling period had a significant effect on mean levels of all fungal-spore categories. Vacuum cleaner type had a marginally significant effect on the indoor spore category, with one high-efficiency vacuum group mean (of three) significantly lower than one control mean. No effect was observed of vacuum cleaner type on outdoor spore categories. Including home-environment variables in analysis of covariance models strengthened the effect of the vacuum-type treatment on the indoor spore category, with no effect on the three outdoor spore categories. Decreased indoor spore levels vs. controls were only observed in high-efficiency vacuum groups during the last sampling period, at the end of the heating season. The results suggest that using a vacuum with high-efficiency filtered exhaust could have some modest effectiveness in controlling airborne fungal-spore exposure in homes when infiltration of outdoor air is very limited.

Associations between acute symptoms and bioaerosol exposure during the collection of household waste.

A study was performed to investigate associations between work-related symptoms and bioaerosol exposure in 22 workers collecting waste separated at source and mixed household waste. Full work shift exposures to bacteria (spherical and rod-shaped) fungal spores, endotoxins, and total dust were measured. Symptoms experienced during work on the day that exposure was measured were recorded by use of a short questionnaire. Questions were posed on respiratory symptoms, systemic effects such as headache, tiredness, and gastrointestinal symptoms. The median exposure levels of bacteria and fungal spores were 0.4 and 0.1 x 10(6)/m3, respectively. The exposure to rod-shaped bacteria (7% of the bacteria count), endotoxins (1.8 EU/m3), and dust (0.2 mg/m3) was low. The symptoms most often reported were unusual tiredness (24%), headache (22%), cough (15%), and irritation in eyes and nose (10 and 17%). These symptoms were also found to be associated to microbial components. The results suggest that acute work-related nose irritation is associated with exposure to bacteria. Rod-shaped bacteria were also associated with nose irritation and unusual tiredness. It is likely that cough is associated to fungal spores, while other associations which were found could be due to confounding.

Increased levels of ambient fungal spores in Taiwan are associated with dust events from China

Fungi are ubiquitous in nature and their spores are often dispersed into the atmosphere through turbulent airstreams. As yellow sandstorm blown from deserts in China had affected the ambient air quality with increasing levels of ambient particulates, often including significant amounts of biologically active particles has therefore become imperative for concerns of their health implications. Our study was aimed to examine the effects of yellow sandstorm events on the fungal composition and concentrations in ambient air. Atmospheric fungal spores were continuously collected using Burkard Volumetric Spore Trap. Samples collected between December 2000 and April 2001 were selected for priority analysis from days when the yellow sandstorms were reported to affect Taiwan according to the Central Weather Bureau in Taiwan. The composition of dominant spores such as Basidiospore, Penicillium/Aspergillus, Nigrospora, Arthrinium, Curvularia, Rusts, Stemphylium, Cercospora, Pithomyces, and unidentified fungi were significantly higher than those of background days. The increase of Basidiospore, Penicillium/Aspergillus, Nigrospora, and those unidentified fungi seems to be significantly associated with the increase of ambient particulate levels with regression coefficients ranging from 0.887 to 31.98. Our study has identified increasing ambient concentrations during sandstorm episodes are observed for some major fungi, Basidiospore, Penicillium, Aspergillus, and those unidentified fungi and the trends of the increase seems to associate with ambient particulate levels. Further efforts to clarify the relationship between those high fungal spore exposures and clinical adverse health effects are suggested in the future. In addition, effects of climatic factors and other particulate levels on the variation of ambient fungal spore levels are also desired in further study. Additional monitoring of ambient fungal spores in the first line of west coastline is hoped to assist in differentiating changes of local spores and contribution for sandstorms during the episodes.

An Investigation into Techniques for Cleaning Mold-Contaminated Home Contents

This study examined the efficacy of the following treatments to reduce selected fungal spore and mycotoxin levels on materials commonly found in home contents: (1) gamma irradiation at a 10–13 kiloGray exposure, (2) a detergent/bleach wash, and (3) a steam cleaning technique. A minimum of six replicates were performed per treatment. Paper, cloth, wood, and carpet were inoculated with either fungal spores (Stachybotrys chartarum, Aspergillus niger, Penicillium chrysogenum, or Chaetomium globosum) at 240,000 spores/2.54 cm2 of material or with the mycotoxins roridin A, T-2, and verrucarin A at 10 μg per 2.54 cm2of material. Treatments were evaluated with an agar plating technique for fungal spores and a yeast toxicity culture assay for mycotoxins. Results showed that gamma irradiation inactivated fungal spores, but the treatment was not successful in inactivating mycotoxins. The washing technique completely inactivated or removed spores on all materials except for C. globosum, which was reduced on all items except paper (p < 0.05). Washing inactivated all mycotoxins on paper and cloth but not on carpet or untreated wood (p < 0.001). The steam cleaning treatment did not completely eliminate any fungal spores; however, it reduced P. chrysogenum numbers on all materials, C. globosum was reduced on wood and carpet, and S. chartarum was reduced on wood (p < 0.05). Steam cleaning was unsuccessful in inactivating any of the tested mycotoxins. These results show that the bleach/detergent washing technique was more effective overall in reducing spore and mycotoxin levels than gamma irradiation or steam cleaning. However, the other examined techniques were successful in varying degrees.

Intervention study of airborne fungal spora in homes with portable HEPA filtration units

The concentrations and composition of airborne fungal spores in homes fitted with portable HEPA filtration units were examined to provide information to evaluate the importance of varying levels of fungal spores in residential environments in Perth, Australia. A novel method for simulating activity/impaction on carpeted environments was also investigated. Reductions in fungal (35%) and particulate (38%) levels were achieved in the air filter homes. Penicillium, Cladosporium and yeasts were the most common and widespread fungi recovered indoors and outdoors. Fungal range decreased over the study period but this could be due to an overall reduced dissemination of spores (less spores in the air).

Volumetric assessment of airborne fungi in two sections of a rural indoor dairy cattle shed

There is increasing concern about the exposure to fungal aerosols in occupational environments and associated respiratory allergic diseases and asthma. A large number of people work in cattle sheds around the world, pulmonary function impairments and higher frequency of respiratory symptoms have been reported in dairy farmers; however, it appears that adequate information on the fungal aerosols from the cattle sheds are largely lacking. Volumetric assessment of airborne culturable and nonculturable fungal spores was performed in two sections of a large rural indoor cattle shed of West Bengal, India for 2 consecutive years. An Andersen Two Stage Viable Sampler was used for sampling culturable fungi and a Burkard Personal Slide Sampler was used to collect the total airborne fungal spores including both the culturable and nonculturable types. A total of 31 spore types and 35 types of viable colony-forming units were recorded. Average concentration range of total fungal spores was 233–2985/m 3 and concentration of viable colony-forming units ranged between 165 and 2225 CFU/m 3. Burkard Sampler showed higher frequencies of Aspergilli/Penicilli, Cladosporium, Alternaria, and smut spores. Andersen Sampler showed the prevalence of Aspergillus niger, Aspergillus flavus and Cladosporium cladosporioides colonies. Some recorded fungi were earlier reported as allergenic, toxic, and pathogenic for occupational workers as well as cattle population. Higher concentration levels of airborne total and culturable fungal spores were recorded during the months of November through February (winter) and June through September (late summer and rainy season).

Isolation, identification and seasonal distribution of airborne and waterborne fungi in Terkos Lake (Istanbul-Turkey).

This paper focuses on isolation and identification of airborne and waterborne fungi from different parts of Terkos Lake located in Istanbul (Turkey). The quantitative and qualitative fungal composition of the air and water of the Lake was surveyed monthly for a year (August 2000-July 2001). Water samples were taken at five different stations at Terkos Lake. Airborne fungal spore levels were estimated by exposing a petri dish containing Rose-Bengal streptomycin agar medium to air for 15 minutes. A total of 2372 fungal colonies (1032 from air and 1340 water) was counted on 216 petri plates. We isolated twenty mould species belonging to 9 genera. Scopulariopsis brevicaulis, Penicillium expansum and Cladosporium herbarum were the most abundant species (22.0%, 13.4% and 12.9%, respectively). Cladosporium herbarum and sphaerospermum are very common in air samples (29.7% and 27.0%, respectively). Many of the species isolated are rarely in the atmospheric and water environment such as Aspergillus niger and Cladosporium variabile. Statistical analysis revealed a positive correlation between total CFUs and a number of environmental factors.

Comparison of pre-and post-remediation fungal spore levels

Comparison of pre-and post-remediation fungal spore levels

Airborne pollen in Padua (NE-Italy): A comparison between two pollen samplers

During recent years a gradual decrease inallergenic airborne pollen concentration hasbeen observed in the monitoring station ofPadua (Italy). Because technical checks of thesampler were not able to explain this trend,the results obtained from two twinpollen-samplers (Lanzoni VPPS 2000), placed twometres apart, were compared.An eight-week sampling was carried out duringthe year 2000 from July to September.Subsequent analysis revealed no statisticallysignificant difference between the dataobtained with the two instruments. On the otherhand, both samplers captured high levels offungal spores. We conclude that the observednegative trend in pollen count is real and notrelated to technical biases.

The role of symptomatic colds in asthma exacerbations: Influence of outdoor allergens and air pollutants

Background: Both air pollutants and respiratory viral infections have been recognized to be important triggers of asthma exacerbations, but the possible interaction of these has not been assessed in an epidemiologic study. Objective: In this study, we aimed to assess the possible associations of symptomatic colds with outdoor allergens and air pollutants in exacerbating asthma. Methods: A total of 57 adults and children with asthma participated in a 1-year study in Vancouver, British Columbia. Diary cards recording symptoms of asthma and colds, medication usage, and peak expiratory flow rates were completed twice daily. Outdoor air pollutant levels and levels of pollen and fungal spores were measured. Levels were examined for associations with exacerbations of asthma with symptoms of a cold, as compared with asthma exacerbations with no cold symptoms and colds in the absence of asthma exacerbations. Results: Of 130 asthma exacerbations, 47% were associated with cold symptoms (accounting for 44% of episodes of colds). Asthma exacerbations with colds were associated with higher levels of sulfur dioxide, and nitric oxide during March to November in comparison with asthma exacerbations without cold symptoms ( P < .018). Cold-symptom days overall were more common in winter and were significantly associated with lower temperatures, lower ozone levels, and higher sulfur dioxide, nitrogen dioxide, nitrogen oxide (NO and NO x), and carbon monoxide levels. Conclusions: Asthma exacerbations are commonly associated with cold symptoms. These episodes are associated with higher levels of sulfur dioxide and nitrogen oxides from March to November in comparison with asthma exacerbations without cold symptoms. (J Allergy Clin Immunol 2001;108:52-8.)

Environmental allergen avoidance: An overview

Environmental allergen avoidance: An overview

Airborne bacteria and fungal spores in the indoor environment. A case study in Singapore

AbstractThe concentration of airborne fungal spores and bacteria as related to room temperature, humidity and occupancy levels within a library building in Singapore was determined. Measurement of indoor air quality with respect to microorganisms is of particular importance in tropical environments due to the extensive use of air‐conditioning systems and the potential implications for human health. This study has revealed a number of interesting relationships between the concentrations of fungal spores and bacteria in relation to both environmental and human factors. The levels of fungal spores measured in the indoor environment were approximately fifty times lower than those measured outside, probably because of the lowered humidity caused by air‐conditioning in the indoor environment. The variation in fungal spore concentration in the outdoor environment is likely to be due to the diurnal periodicity of spore release and the response to environmental factors such as light temperature and humidity. The indoor concentration of fungal spores in air was not clearly correlated to concentrations measured in air outside of the library building and remained relatively constant, unaffected by the difference in the numbers of occupants in the library. In contrast, the indoor concentrations of bacteria in air were approximately ten times higher than those measured outdoors, indicating a signficant internal source of bacteria. The elevated levels of indoor bacteria were primarily attributed to the number of library occupants. Increased human shedding of skin cells, ejection of microorganisms and particulates from the respiratory tract, and the transport of bacteria on suspended dust particles from floor surfaces probably accounts for the strong positive correlation between occupancy levels and the concentration of bacteria in internal air.

Indoor airborne fungal spores, house dampness and associations with environmental factors and respiratory health in children.

Children living in a damp house are more likely to suffer from respiratory symptoms and it has been suggested that exposure to fungi is an important contributing factor. However, more knowledge about underlying mechanisms for the association are needed. To identify associations between measures of house dampness, levels of airborne fungal spores, housing factors and health outcomes in children. Eighty households with 148 children between 7 and 14 years of age were recruited in the Latrobe Valley, Victoria, Australia. Some 36% of participating children were asthmatic. Six sampling visits were made to each house between March 1994 and February 1995 on a 2-monthly cycle. Samples for airborne total and viable fungal spores were collected from bedrooms, living rooms, kitchens and outdoors. A detailed dwelling characterization, using a questionnaire and inspection surveys, was carried out. Skin-prick tests were performed with extracts of common aeroallergens and a respiratory questionnaire was completed for each child. Large airborne fungal spore concentrations were recorded in association with: musty odour, water intrusion, high indoor humidity, limited ventilation through open windows, few extractor fans and failure to remove indoor mould growth. Visible mould growth or condensation evidence was associated with large concentrations of Cladosporium spores, but not with large total spore concentrations. Penicillium exposure was a risk factor for asthma, while Aspergillus exposure was a risk factor for atopy. Fungal allergies were more common among children exposed to Cladosporium or Penicillium in winter or to musty odour. Respiratory symptoms were marginally more common with exposure to Cladosporium or total spores in winter. Indoor exposure to certain fungal genera in winter was a risk factor for asthma, atopy and respiratory symptoms in children. On the other hand, no significant associations were seen between average viable or total spore concentrations and child health. Actual measurements of fungal spores predict health outcomes better than reported dampness.

Pollen and fungal spores indoor and outdoor of mobile homes.

Allergenic diseases triggered by aeroallergens extract a health cost in quality of life and in economic impact. People generally spend 90% to 95% of their time indoors, so understanding the environmental factors that affect the presence of aeroallergens indoors are important in understanding health impact and potential intervention methods. Describe the relationship of indoor airborne pollen and fungal spores in occupied mobile homes with outdoor concentrations and other environmental factors within geographically diverse areas of Texas. Airborne pollen and fungal spores were collected during the daytime with RotoRod samplers indoor and outdoor of mobile homes in Houston and El Paso, Texas. Samples were counted simultaneously with a dual eyepiece microscope and identified morphologically and through staining techniques. Geometric mean concentrations (counts/m3) indoors and outdoors for pollen, respectively, were Houston 7.1 and 196.4; and El Paso 17.5 and 71.5. Geometric mean concentrations (counts/m3) indoors and outdoors for spore, respectively, were Houston 98.5 and 196.4; and El Paso 36.9 and 71.5. Indoor to outdoor ratios (I/O) for pollen and fungal spores were found to be higher on average than has been previously reported. Modeling of predictive factors in Houston demonstrate that 62% and 41% of indoor levels of pollen and fungal spores, respectively, can be explained by their corresponding outdoor levels. These data suggest that the many factors associated with individual exposure to airborne pollen and fungal spores indoors are under the control of the occupant, and may additionally be influenced by the physical characteristics of mobile homes, in particular the high surface area to volume ratio and restricted flow patterns.

Investigation of contact vacuuming for remediation of fungally contaminated duct materials

Environmental fungi become a potential Indoor Air Quality (IAQ) problem when adequate moisture and nutrients are present in building materials. Because of their potential to rapidly spread contamination throughout a building, ventilation system materials are of particular significance as potential microbial contamination sources. Current recommendations are to discard fibrous glass insulation that appears to be wet or moldy. Unfortunately, this advice is not always followed. Instead, cleaning is sometimes being used in buildings to remediate fibrous glass duct liner that is already contaminated with microbial growth. The objectives of this research program were to: 1) determine, under dynamic test conditions, whether fungal spore levels on heating, ventilating, and air-conditioning (HVAC) duct material surfaces could be substantially reduced by thorough vacuum cleaning, 2) evaluate whether subsequent fungal growth could be limited or contained by mechanical cleaning, and 3) provide data concerning the advisability of cleaning duct materials. The constant high relative humidity (RH) environment to which the test materials were exposed during this study was selected as a favorable growth environment that is frequently found in Southeastern United States HVAC systems. The results showed that, following cleaning, the levels of the two test fungi, A. versicolor and P. chrysogenum, recovered to preclean levels within 6 weeks. Therefore, mechanical cleaning by contact vacuuming alone was able to only temporarily reduce the surface fungal load. The current guidelines to discard contaminated materials should be followed.

Increased levels of airborne fungal spores in response to Populus tremuloides grown under elevated atmospheric CO2

Soil fungi are important components of terrestrial ecosystems. They function as decomposers, pathogens, parasites, and mutualistic symbionts. Their main mode of dispersal is to liberate spores into the atmosphere. In this study we tested the hypothesis that a higher atmospheric CO2 concentration will induce greater sporulation in common soil fungi, leading to higher concentrations of fungal propagules in the atmosphere. In our field experiment, the concentration of airborne fungal propagules, mostly spores, increased fourfold under twice-ambient CO2 concentrations. Analysis of decomposing leaf litter (likely the main source of airborne fungal propagules) indicated that the fungi produced fivefold more spores under elevated CO2. Our results provide evidence that elevations in atmospheric CO2 concentration can directly affect microbial function, which may have important implications for litter decay, fungal dispersal, and human respiratory health. Key words: atmospheric CO2, fungal spores, global change, Populus tremuloides.

A 2‐year survey of the airborne mycoflora in a hospital environment

Studies on levels of airborne fungal spores in hospital wards and a diet kitchen were carried out for a period of 24 months using an air sampler. In a preliminary study using Sabouraud dextrose agar (SDA), SDA with chloramphenicol, acidified malt extract agar, oxytetracycline glucose yeast extract and Rose‐Bengal chloamphenicol varying levels of fungi were recovered on each of these media. Sabouraud medium, which is used to recover medically important fungi, showed relatively lower fungal counts with an average of 89 cfu m‐3 as compared with counts > 210 cfu m‐3 on all the other media. Fungi accounted for about 68% of the total viable counts and the predominant genera were Aspergillus, Fusarium, Monilia, Penicillium, Rhizopus, Monilia, Candida, Rhodotorula and Pichia. Spore counts were higher in the wards (303 cfu m‐3) than in the diet kitchen (208 cfu m‐3) The aerial fungal spore counts were 51% higher in all the areas sampled during the warmer months than the colder months but there was no major change in the types of fungi except that Chrysonilia species were only isolated between October and March when they accounted for < 5% of the total fungal isolates.

Evaluation of airborne particulates and fungi during hospital renovation.

This study was conducted over 30 weeks on a hospital floor undergoing partial renovation. Some patients housed on the floor were immunosuppressed, including bone marrow transplant recipients. The construction zone was placed under negative pressure and was separated from patient rooms by existing hospital walls and via erection of a temporary barrier. Other control measures minimized patient exposure to airborne materials. Air sampling was done for 3 weeks prior to construction, 24 weeks during construction, and 3 weeks after renovation was completed. Airborne particulate concentrations, total spore counts, particle size, and fungal species were assessed. At the beginning of the renovation there were increases in airborne particulates (from 0.2 to 2.0 mg/m3) and fungal spores (from 3.5 to 350 colony forming units (CFU/m3), but only in the construction zone. Throughout the remainder of the renovation, particulate and fungal spore levels fluctuated inside the construction zone but remained close to baseline values in the patient area. When renovation was completed, particulates and spore counts inside the construction zone decreased to preconstruction levels. The primary fungus isolated from air samples was Penicillium. This study demonstrated that control measures were effective in reducing exposures of hospitalized patients to airborne particulates and spores and in reducing the increased risk of aspergillosis and other fungal infections associated with hospital construction projects. The data from this study may be useful in establishing exposure guidelines for other health care settings.

Detection of food poisoning bacteria involves contacting foodstuff with surface acoustic wave element having antibodies attached to surface : Oki Electric Ind. Co. Ltd JP-05034349, 9 February 1993

Chocolate confectionery fillings are generally regarded as microbiologically stable. The stability of these fillings is largely due to the general practice of adding either alcohol or preservatives. Consumer demands are now stimulating producers to move away from adding alcohol or other preservatives to their confectionery fillings and instead to search for innovative formulations. Such changes in composition can influence the shelf life of the product and may lead to spoilage by xerophilic fungi. The aim of this study was to test whether the production environment of Belgian chocolate confectionery factories and common ingredients of chocolate confectioneries could be potential sources of contamination with xerophilic fungal species. In the factory environment, the general and strictly xerophilic fungal spore load was determined using an RCS Air Sampler device in combination with DG18 and MY50G medium, respectively. Four basic ingredients of chocolate confectionery fillings were also examined for fungal spore levels using a direct plating technique. Detected fungi were identified to species level by a combination of morphological characterization and sequence analysis. Results indicated a general fungal spore load in the range of 50–250 colony forming units per cubic meter of air (CFU/m3 air) and a more strict xerophilic spore load below 50 CFU/m3 air. These results indicate rather low levels of fungal spores present in the factory environment. The most prevalent fungi in the factory environment were identified as Penicillium spp., particularly Penicillium brevicompactum. Examination of the basic ingredients of confectionery fillings revealed nuts to be the most likely potential source of direct contamination. In nuts, the most prevalent fungal species identified were Eurotium, particularly Eurotium repens.

Everyday activities and variation of fungal spore concentrations in indoor air

The effects of some everyday activities on concentrations of airborne fungal spores in Finnish home environments were examined to provide basic information needed to evaluate the importance of varying levels of fungal spores in the air. The activities studied were opening of a cellar door, handling of different organic materials, resuspension of spores as a result of cleaning activities and transport of spores on clothes and pets. Airborne spores were sampled using six-stage impactors and surface samples were taken from the materials used in the experiments with sterile swabs or with a vacuum cleaner. Most of the activities had an obvious effect on the spore counts. However, vacuum cleaning, humidifying of house plants and baking caused no marked changes in the spore concentration. The short-term activities studied in a house explain most of the wide variation previously observed in fungal spore concentrations in indoor air. These activities have to be taken into account when designing sampling strategies for airborne fungi, in evaluation of the microbial quality of indoor air and when making comparisons with recommended values.