The incidence of fungal spores in the ambient air and inside homes: Evidence from London

Little research has been carried out in London concerning fungal spore prevalence yet this information may help to elucidate geographical patterns of asthma and hay fever. Although many types of spore reach peak concentrations outdoors in late-summer, the incidences in the indoor environment may be more important through the winter because of heating and poor ventilation. Daily average concentrations of fungal spores in the ambient atmosphere were monitored with a Burkard volumetric spore trap on an exposed roof in North London from autumn 1991 until the summer of 1992. Indoor spore measurements were taken in 19 homes in the vicinity through the winter months, both by direct air sampling using a portable Burkard sampler and by dust culture. Trends in the occurrence and concentrations of fungal spores indoors and outdoors were examined. Relationships between the abundance of selected allergenic fungi and features of the houses were analysed including age of dwelling, dampness, cleanliness and presence of pets.Aspergillus andPenicillium were the most frequently occurring spore types in the homes. Overall, high spore incidence was associated with dampness and dust accumulation. The outdoor spore samples revealed generally low concentrations through the winter until March when concentrations of many types includingCladosporium, Epicoccum andAlternaria increased in abundance in response to the warmer weather. Even during the late-spring and early-summer, concentrations of most fungal spores were notably below those reported for rural sites.     

Airborne fungi in the hospitals of metropolitan Delhi

Summary The fungal airspora of a large hospital in Delhi Metropolis was studied from May 1989 – April 1991, using Andersen Six Stage Volumetric Sampler and Burkard Personal Slide Sampler. Simultaneously, samples were also collected from outside the hospital to act as a control. Samplers were operated for 10 min. each time, at 10 - day intervals. Additional samples were also collected from different sections of 3 other hospitals. Some of the dominant forms encountered wereCladosporium spp.,Aspergillus flavus, Smut,Fusarium spp.,Aspergillus niger, Alternaria spp.,Penicillium citrinum, Aspergillus versicolor, andPenicillium oxalicum. Aspergillus flavus showed significantly high concentration inside hospital (n=66, x=53 CFU m^–3, p<0.05) as compared to outside air. The peak period for fungi was observed to be from June – September. The spore concentration was much lower in hospital units receiving filtered air as compared to control environment, but in naturally ventilated hospitals the concentration was similar to that of outside air.     

Main airborne Ascomycota spores: characterization by culture, spore morphology, ribosomal DNA sequences and enzymatic analysis

The aim of this work was to identify the main allergy-related Ascomycetes fungal spores present in the atmosphere of Porto, using different and complementary techniques. The atmospheric sampling, performed in the atmosphere of Porto (Portugal) from August 2006 to July 2008, indicated Cladosporium, Penicillium, Aspergillus and Alternaria as the main fungal spore taxa. Alternaria and Cladosporium peaks were registered during summer. Aspergillus and Penicillium highest values were registered from late winter to early spring. Additionally, the Andersen sampler allowed the culture and isolation of the collected viable spores subsequently used for different identification approaches. The internal-transcribed spacer region of the nuclear ribosomal repeat unit sequences of airborne Ascomycetes fungi isolates revealed 11 taxonomically related fungal species. Among the identified taxa, Penicillum and Aspergillus presented the highest diversity, while only one species of Cladosporium and Alternaria, respectively, were identified. All selected fungal spore taxa possessed phosphatase, esterase, leucine arylamidase and β-glucosidase enzymatic activity, while none had lipase, cystine arylamidase, trypsin or β-glucuronidase activity. The association between the spore cell wall morphology, DNA-based techniques and enzymatic activity approaches allowed a more reliable identification procedure of the airborne Ascomycota fungal spores.     

A comparative study on the airborne fungi in Athens,Greece, by viable and non-viable sampling methods

Airborne fungi were studied in the city of Athens using two complementary methods in which 136 concurrent samplings were carried out during the 12-month period from January until December 1998. A portable Burkard air sampler for agar plates was used for trapping the culturable portion of the mycobiota. Nineteen genera of fungi were identified and assessed in terms of total numbers and fluctuations in concentration (Alternaria, Arthrinium, Aspergillus, Aureobasidium, Botrytis, Chrysonilia, Cladosporium, Drechslera, Epicoccum, Fusarium, Mucor, Nigrospora, Paecilomyces, Penicillium, Rhizopus, Sclerotinia, Scopulariopsis, Trichoderma and Ulocladium), with the exception of those included in the Sphaeropsidales, the yeasts, and the non-sporulating fungi, which were counted as groups. A volumetric Burkard air sampler for glass slides was operating simultaneously for detecting the total mycobiota, including the non-culturable and the non-viable portion. Ascospores, basidiospores, spores of Myxomycetes, Ustilaginales, Uredinales and Erysiphales, teliospores of Puccinia, as well as conidia of the genera Curvularia, Helminthosporium, Periconia, Pestalotiopsis, Pithomyces, Polythrincium, Stachybotrys, Stemphylium and Torula were also recorded. Only seven of the genera were recovered by both samplers. The total numbers of fungal spores, which had a maximum concentration of 3,175 spores/m³, as well as the spore concentrations of the genera Cladosporium (2,565 spores/m³) and Alternaria (280 spores/m³) were underestimated by the viable method (2,435 CFU/m³ for the total, 2,169 CFU/m³ for Cladosporium and 180 CFU/m³ for Alternaria). The non-viable method fails to resolve the identification of the genera Penicillium and Aspergillus, which are major components of the airborne mycobiota (1,068 CFU/m³ and 204 CFU/m³, respectively) based on recovery by the viable method.     

Possible cause of allergy for the librarians: books manipulation and ventilation as sources of fungus spores spreading

The objective of this study was to investigate the airborne viable spore concentrations and identify the fungal species in all indoor spaces from the lending library at the Technical University “Gheorghe Asachi” Iaşi, Romania. Samples were collected using the settle plate method and swab samples from PC cooler fan grids as well as from the wall in it’s vicinity and from paper/wood fragments. There were no air conditioning systems in the library rooms. The heating systems were standard with an environmental temperature of 20°C in winter, except for the storage area of old/rare books stacks II, where the temperature was below 15°C and the humidity was very high due to water infiltrations in the walls and poor maintenance. More than 296 fungal colonies from over 78 samples were identified, enumerated, and reported. Indoor airborne fungal spore deposition rates were within the range of 419–1,677 CFU/m², with the predominance of genera being Aspergillus spp., Penicillium spp., Cladosporium spp., Alternaria spp. and Chaetomium spp. Approximately ten fungal colonies could not be identified. The PC fans move particles from the low levels (floor) to the air, and are thus responsible for maintaining a constant air velocity and contribute to fungal-spore aerosolization, transport, deposition and resuspension. Book paper and wood furniture are known to be suitable substrates for cellulose degrading fungi.     

Hourly predictive artificial neural network and multivariate regression tree models of <Emphasis Type="Italic">Alternaria</Emphasis> and <Emphasis Type="Italic">Cladosporium</Emphasis> spore concentrations in Szczecin (Poland)

A study was made of the link between time of day, weather variables and the hourly content of certain fungal spores in the atmosphere of the city of Szczecin, Poland, in 2004–2007. Sampling was carried out with a Lanzoni 7-day-recording spore trap. The spores analysed belonged to the taxa Alternaria and Cladosporium. These spores were selected both for their allergenic capacity and for their high level presence in the atmosphere, particularly during summer. Spearman correlation coefficients between spore concentrations, meteorological parameters and time of day showed different indices depending on the taxon being analysed. Relative humidity (RH), air temperature, air pressure and clouds most strongly and significantly influenced the concentration of Alternaria spores. Cladosporium spores correlated less strongly and significantly than Alternaria. Multivariate regression tree analysis revealed that, at air pressures lower than 1,011 hPa the concentration of Alternaria spores was low. Under higher air pressure spore concentrations were higher, particularly when RH was lower than 36.5%. In the case of Cladosporium, under higher air pressure (>1,008 hPa), the spores analysed were more abundant, particularly after 0330 hours. In artificial neural networks, RH, air pressure and air temperature were the most important variables in the model for Alternaria spore concentration. For Cladosporium, clouds, time of day, air pressure, wind speed and dew point temperature were highly significant factors influencing spore concentration. The maximum abundance of Cladosporium spores in air fell between 1200 and 1700 hours.     

Occurrence of fungal spores in the respiratory tract and homes of patients with positive skin test to fungi

The occurrence of fungal spores in the upper respiratory tract and in the homes of 86 patients with allergic manifestations and positive skin tests for fungi has been investigated.Alternaria tenuis andCladosporium herbarum have been more frequently found to give positive reactions, followed byAspergillus mix,Candida albicans andPenicillium notatum. Cladosporium andAlternaria represented also the most common moulds isolated from nasal specimens. The prevalent fungi isolated from patients' environments wereCladosporium, Penicillium andAlternaria, occurring respectively in 93%, 78% and 72% of the homes sampled. An examination of individual cases have revealed a surprisingly close correlation, in 47 out of 86 patients, between positive skin test response and presence in high amount of the same fungi in patient's respiratory tract and home. In the majority of cases the fungi involved wereAlternaria and/orCladosporium.     

Seasonal and intradiurnal variation of allergenic fungal spores in urban and rural areas of the North of Portugal

Because fungal spore emission intensity varies throughout the year and even throughout the day, study of the hourly distribution is an important aspect of aerobiological monitoring. The objective of this work was to determine seasonal and intradiurnal variation of allergenic airborne fungal spores in urban and rural areas. The aerobiological study was performed from 2005 to 2007 using Hirst-type volumetric spore traps. Fungal spore types (Cladosporium, Alternaria, and Aspergillus/Penicillium) were selected according to their allergenic capacity and their frequency in the atmosphere. Cladosporium was the most frequent fungal spore in both locations, together with Alternaria; its concentration was higher during summer whereas Aspergillus/Penicillium was more abundant during autumn. Alternaria and Cladosporium maximum daily spore concentration was reached from 16.00 to 20.00 h. Aspergillus/Penicillium spore distribution differed in the two locations, and although it was difficult to establish a distribution pattern the highest concentration were found during the night. Determination of periods of high concentration may help allergic patients to avoid the daily periods when the allergen concentration is highest.     

Selected airborne allergenic fungal spores and meteorological factors in Szczecin,Poland, 2004–2006

Airborne fungal spore concentrations in Szczecin, Poland, were studied between 2004 and 2006 with the objective of determining a seasonal variation in the concentrations of selected fungal spore types in relation to meteorological parameters. The presence of spores of five taxa, namely, Cladosporium, Ganoderma, Alternaria, Leptosphaeria and Didymella, was recorded using a volumetric method (Hirst type). Fungal spores were present in the air in large numbers during the summer, with the highest concentrations recorded mainly in June, July and August. The peak concentrations of two of the studied spore types, Ganoderma and Alternaria, occurred in August, while the concentrations of Cladosporium, Leptosphaeria and Didymella spores were the highest in July. Multiple regression analysis was performed for three fungal seasons—2004, 2005 and 2006. Spore concentration was found to be positively correlated with the minimum temperature. For some spore types, there was also a significant correlation between concentrations, relative humidity and rain.     

Identification and seasonal distribution of airborne fungi in three horse stables in Italy

Fungal agents are responsible for a variety of respiratory diseases both in humans and animals. The nature and seasonal variations of fungi have been investigated in many environments with wide ranging results. The aims of the present report were (i) to evaluate the quality and magnitude of exposure to airborne fungi in three differently structured equine stalls (open air, partially and completely enclosed buildings) during a one-year period, using an air sampling technique and (ii) to compare the distribution and frequency of fungal species, with regards to these different environments. Air samples were collected monthly from December 2001 to November 2002 by means of a surface air sampler (SAS) Super-90, (PBI International, Milan, Italy). Penicillium and Aspergillus spp. were cultured from all the stables in all seasons. Mucoraceae were also recovered in all seasons in stalls 1 and 2, while they were not isolated in spring and fall in stall 3. These fungi were detected in 28.4%, 72.9% and 60.5% of the total number of samples, respectively. Other fungal genera such as Alternaria, Cladosporium, Fusarium, Beauveria and Drechslera were also occasionally recovered.Viable fungal concentrations varied greatly, ranging from below the limit of detection to more than 3000 CFU/m³ for stables 1 and 2, and 1750 CFU/m³ for stable 3. The median fungal concentration was approximately 178 CFU/m³. Total fungal concentration appeared to be highest in summer, winter and spring, and lowest in the fall.     

Occurrence of fungal spores in the respiratory tract and homes of patients with positive skin test to fungi

The occurrence of fungal spores in the upper respiratory tract and in the homes of 86 patients with allergic manifestations and positive skin tests for fungi has been investigated.Alternaria tenuis andCladosporium herbarum have been more frequently found to give positive reactions, followed byAspergillus mix,Candida albicans andPenicillium notatum. Cladosporium andAlternaria represented also the most common moulds isolated from nasal specimens. The prevalent fungi isolated from patients' environments wereCladosporium, Penicillium andAlternaria, occurring respectively in 93%, 78% and 72% of the homes sampled. An examination of individual cases have revealed a surprisingly close correlation, in 47 out of 86 patients, between positive skin test response and presence in high amount of the same fungi in patient's respiratory tract and home. In the majority of cases the fungi involved wereAlternaria and/orCladosporium.     

Aerobiological investigations inside repositories of the National Archive of the Republic of Cuba

The objectives of this study were to evaluate the microbial prevalence inside six repositories of the National Archive of the Republic of Cuba in 2?months of the year and to examine some of the physiological features of fungi isolated in order to evaluate their potential for biodeterioration. The microbiological sampling was conducted in February and September using a slit impactor as air sampler. Appropriate selective culture media were used to isolate fungi and bacteria. Temperature and relative humidity were measured during the samplings. The cellulolytic activity and the production of acids and pigments of the fungi isolated were qualitatively determined. Total viable microbiota and bacteria concentrations were greater in February while the fungal concentration was higher in September. Aspergillus, Cladosporium, Penicillium, Curvularia and Alternaria were the predominant fungal genera in February while Cladosporium prevailed in September, although Fusarium, Mucor and Neurospora genera were also isolated in this month. The fungi isolated were capable of degrading cellulose and excreting pigments and acids. The Gram-positive bacteria group prevailed in the air and Corynebacterium, Streptomyces, Bacillus, Streptococcus, Staphylococcus, Enterobacter and Serratia were some of the genera identified.     

Status of airborne spores and pollen in a coir factory in Kerala,India

The prevalence of airborne fungal spores and pollen grains in the indoor and outdoor environments of a coir factory in Thiruvananthapuram district of Kerala state, India was studied using the Burkard Personal Sampler and the Andersen 2-stage Sampler for 2 years (September 1997 to August 1999). The concentration of pollen grains was remarkably lower than that of fungal spores (ratio of 1:28). There was no large difference in the concentrations and types of fungal spores between the indoor and outdoor environments, with 26 spore types found to be present indoors and 27 types outdoors; of these, 22 were common to both the environments. Aspergillus/Penicillium, Cladosporium, ‘other basidiospores’ and ascospores were the dominant spore types. The total spore concentration was highest in February and lowest in September, and it was significantly higher in 1998–1999 than in 1997–1998. Twenty viable colony-forming types were isolated from inside the coir factory. The most dominant viable fungi isolated were Penicillium citrinum, Aspergillus flavus and Aspergillus niger. The total pollen concentration was higher in the outdoor environment of the coir factory than indoors, with 15 and 17 pollen types, respectively. Grass and Cocos nucifera pollen types were dominant. The dominant spore and pollen types trapped in the two environments of the coir factory are reportedly allergenic and, consequently, workers are at risk of catching respiratory/allergic diseases.     

Incidence of allergenically significant fungal aerosol in a rural bakery of West Bengal,India

The frequency of fungal spores in the air of three different sections of a rural bakery was analyzed using a Burkard personal slide sampler and Andersen two stage viable sampler. In average concentration of spores (No./m³) was 228–26770/m³ and concentration of viable colony forming units (CFU/m³) was 65-2061 CFU/m³. Dominant fungus species both culturable and nonculturable, were species of Aspergillus and Penicillium, Cladosporiumsp., Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Cladosporium cladosporioides, Penicillium citrinum and Alternaria alternata. Seasonal variations in the spore concentrations were clearly observed in case of some fungi. Total culturable mould concentration of different bakery sections sometimes exceeded the acceptable limit for a healthy indoor environment. Antigenic extracts prepared from some dominant culturable fungi showed high level of allergenicity in skin prick tests indicating that they could be responsible for allergic respiratory dysfunction of bakery workers.This revised version was published online in October 2005 with corrections to the Cover Date.     

Antifungal activity of Δ3-alstovenine, a plant alkaloid isolated fromAlstonia venenata

A plant quaternary alkaloid Δ³-alstovenine inhibited the spore germination of most of the fungi tested at concentration of 250–1000 mg/L. Saprophytic and biotrophic fungi were equally sensitive to the alkaloid.Cercospora sp. was the most sensitive as 100% inhibition of spore germination was observed at 250 mg/L.Alternaria species,Curvularia species andFusarium udum were not affected even at 1000 mg/L.     

Survey of bioaerosol in different indoor working environments in central India

Aerobiological studies at three different indoor sitesviz., food grain godowns, library building and bakerywere carried out. The main objective of the study wasto find out the fungal flora at these places and itsimpact on the organic materials which are stored /processed there. The study reveals that over 40fungal types prevail in such organic matter richenvirons. The incidence of fungi was found to befluctuating according to months and seasons. Studieswere carried out by Andersen two stage sampler. Maximum spore concentration was observed in thelibrary followed by bakery and food grain godowns. Common spore types belonged to the species of Aspergillus. Alternaria, Cladosporium,Helminthosporium, Curvularia, Rhizopus etc. Suchfungi are mainly responsible for the deterioration ofpaper materials in library and food grains in godowns. Bakery products also get contaminated with a goodnumber of fungi types. The people working at suchplaces also get allergic due to these fungalcomponents.     

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.     

A fungal spore calendar for the atmosphere of Melbourne, Australia, for the year 1993

A calendar of fungal spore seasons for Melbourne during 1993was established using a 7-day volumetric Burkard trap. Twenty-ninegenera and five spore groups were identified. The dominant spore typesdetected were Cladosporium (41.7%),Leptosphaeria (14.9%), Coprinus (14.6%),`Ascospore 1' (5.5%), Ganoderma (2.1%) andAlternaria (1.4%). Seasonally, spore levels ofCladosporium and Alternaria peaked in spring andsummer, Leptosphaeria and Ganoderma peaked towardsummer and autumn, `Ascospore 1' peaked in winter, whilst spore levelsof the basidiomycete Coprinus fluctuated year round. Inconclusion, a range of allergenic fungal spores were present in the airof Melbourne throughout the year.     

Ten types of microscopically identifiable airborne fungal spores at Leiden,The Netherlands

A universal method for the complete assessment of atmospheric fungal spores does not exist, which is continuous, volumetric and non-selective, and offers at the same time reliable identification of the collected spores. To perform a survey of airborne fungal spores, a choice has to be made between a viable and non-viable method. For the study carried out in Leiden, the non-viable, continuous volumetric method has been employed, showing the results over a period of 10 years, for 10 microscopically identifiable fungal spore types. Of this selection,Cladosporium spores have by far the highest airborne quantities, with an average annual total of the daily averages of over 700 000.Botrytis, Ustilago andAlternaria follow with much lower spore concentrations of between 20 000 and 30 000 as annual totals. The spore types ofEpicoccum, Erysiphe, Entomophthora, Torula, Stemphylium, andPolythrincium are represented with annual sums lower than 10 000. A spore calendar shows the overall seasonal appearance of the 10 selected types.     

Airborne fungi in an Italian rice mill

Summary Studies employing volumetric spore trap (VSP) and gravity settling culture plates (GSC) were conducted in order to analyse the air spora of a rice mill at Pavia, Italy, from October-December 1988. Results revealed a variety of fungal spores belonging to different genera and including recognized rice pathogenic fungi. The most frequent genera by GSC method includedAcremonium, Alternaria, Aspergillus, Aureobasidium, Cladosporium, Epicoccum, Fusarium, Helminthosporium, Mucor, Nigrospora, Penicillium, Rhizopus, Trichoderma, Trichothecium, and some unidentified fungi. Environmental assessment of fungal spores by VSP revealed that the most prevalent fungi were:Alternaria, Cladosporium, Epicoccum, Helminthosporium, Nigrospora, Pyricularia, Tilletia and hyaline, dark and coloured types of ascospores and basidiospores. Airborne fungal spore concentrations were particularly high (5,000–6,000 spores/m³) in the rooms of the rice mill where the initial stages of rough rice transformation take place, and dropped to 2,500 spores/m³ in the last room, where workers are. During a temporary interruption of the working processes, air spora concentration dropped below 1,000 spores/m³.Cladosporium, Epicoccum andNigrospora spores were predominant in all subdivisions of the indoor environments of the rice mill.