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.     

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.     

The variation in spore concentrations of selected fungal taxa associated with weather conditions in Szczecin,Poland, 2004–2006

The investigation of airborne fungal spore concentrations was carried out in Szczecin, Poland between 2004 and 2006. The objective of the studies was to determine a seasonal variation in concentrations of selected fungal spore types due to meteorological parameters. The presence of spores of ten taxa: Cladosporium, Ganoderma, Alternaria, Epicoccum, Didymella, Torula, Dreschlera‐type, Polythrincium, Stemphylium and Pithomyces was recorded in Szczecin using a volumetric method (Hirst type). Fungal spores were present in the air in large numbers in summer. The highest concentrations were noted in June, July and August. The peak period was recorded in August for most of the studied spore types: Ganoderma, Alternaria, Epicoccum, Dreschlera‐type, Polythrincium and Stemphylium. Cladosporium and Didymella spores reached their highest concentrations in July while concentrations of Torula were highest in May and Pithomyces in September. Multiple regression analysis was performed for three fungal seasons: 2004, 2005, and 2006. Spore concentrations were positively correlated with minimum temperature for seven spore types in 2004, for five spore types in 2005, and for eight spore types in 2006 (significance level of α = 0.05). Some spore types are also significantly correlation among their concentrations, pressure, relative humidity and rain. Minimum temperature appeared to be the most influential factor for most spore types.     

Considerations in the grouping of plant and fungal taxa for an epidemiologic study

Although exposure to airborne pollen grains and fungal spores has been implicated as a causative factor for acute exacerbation of asthma, the few epidemiologic studies that have attempted to evaluate the relationship between these bioaerosols and asthma have used only total counts (ignoring the relative importance of different taxa) or a few predominant pollen or spore types (ignoring less abundant but potentially relevant groups). This paper reports the development of hypothesis‐driven exposure metrics (based on known aeroallergen associations with allergic asthma and other hypersensitivity diseases, pollen allergen cross‐reactivity, and the presence of local sources in the city of Fresno, California, USA) for a 3.5 year epidemiologic study of childhood asthma. Outdoor regional and neighborhood concentrations of pollen and spores were measured using Hirst‐type, 7‐day samplers. Indoor and outdoor residential concentrations were measured at 84 selected homes with similar 24‐hour slit impactors. All pollen and spore concentrations were recorded in 2‐hour intervals to assist in understanding diurnal fluctuations in aeroallergen concentrations, identify exposures during the time periods that children are outdoors, and study interaction between aeroallergens and other air contaminants, which were the primary focus of the study. The 124 pollen taxa that were observed were reduced to 15 categories and the 66 fungal and algal taxa were reduced to five categories that will be used in microenvironmental models to generate individual daily exposure estimates for each of the 315 children. These new exposure metrics will allow examination of health effects for taxa traditionally associated with allergy and those with locally elevated concentrations in combination with exposures to other indoor and outdoor air contaminants.     

Analysis of the predicting variables for daily and weekly fluctuations of two airborne fungal spores: <Emphasis Type="Italic">Alternaria</Emphasis> and <Emphasis Type="Italic">Cladosporium</Emphasis>

Alternaria and Cladosporium are two fungal taxa whose spores (conidia) are included frequently in aerobiological studies of outdoor environments. Both spore types are present in the atmosphere of Malaga (Spain) throughout almost the entire year, although they reach their highest concentrations during spring and autumn. To establish predicting variables for daily and weekly fluctuations, Spearman's correlations and stepwise multiple regressions between spore concentrations (measured using a volumetric 7-day recorder) and meteorological variables were made with results obtained for both spore types in 1996 and 1997. Correlations and regressions were also made between the different taxa and their concentrations in different years. Significant and positive correlation coefficients were always obtained between spore concentrations of both taxa, followed by temperature, their concentrations in different years, sunshine hours and relative humidity (this last in a negative sense). For the two spore types we obtained higher correlation and regression coefficients using weekly data. We showed different regression models using weekly values. From the results and a practical point of view, it was concluded that weekly values of the atmospheric concentration of Alternaria spores can be predicted from the maximum temperature expected and its concentrations in the years sampled. As regards the atmospheric concentration of Cladoposrium spores, the weekly values can be predicted based on the concentration of Alternaria spores, thus saving the time and effort that would otherwise be employed in counting them by optical microscopy.     

Pollen and fungal spore sampling and analysis. Statistical evaluations

Statistical evaluations of samples obtained from a Burkard seven-day recording volumetric pollen/spore trap were performed to determine the precision of the sampling and analysis procedures. The reproducibility of co-located traps was also investigated. The results showed that pollen grain transect counting was not significantly different, while fungal spore counting produced statistically different results. There was no statistical difference in the number of pollen and fungal spores counted between the co-located samplers. Reasons for the differences in the fungal spore counts are presented.     

Seasonality in Antarctic Airborne Fungal Spores

Airborne fungal spores were monitored over periods of up to 131/2 months at three sites on Signy Island in the maritime Antarctic. Fungal spore concentrations in the air were much lower than in other parts of the world. Concentrations were very low during the austral winter but increased during the austral summer. Chlamydospores were the most abundant fungal spore type found. Spores of Cladosporium spp. were the second most frequently trapped form. All spore types samples were most abundant in the summer months, except for chlamydospores, which were most numerous during the winter. The concentration of Cladosporium spores in the air at Signy Island was compared with the concentrations of this spore type found in the air in other parts of the world. It was evident that Cladosporium loses its dominance as the most abundant component of the air spora with increasingly high latitude. The peak concentration of fungal spores occurred at two sites following the start of the thaw; at the third site, the peak occurred with the arrival of spores by long-distance transport from more northerly regions.     

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.     

Gamma,Gaussian and logistic distribution models for airborne pollen grains and fungal spore season dynamics

The characteristics of a pollen season, such as timing and magnitude, depend on a number of factors such as the biology of the plant and environmental conditions. The main aim of this study was to develop mathematical models that explain dynamics in atmospheric concentrations of pollen and fungal spores recorded in Rzeszów (SE Poland) in 2000–2002. Plant taxa with different characteristics in the timing, duration and curve of their pollen seasons, as well as several fungal taxa were selected for this analysis. Gaussian, gamma and logistic distribution models were examined, and their effectiveness in describing the occurrence of airborne pollen and fungal spores was compared. The Gaussian and differential logistic models were very good at describing pollen seasons with just one peak. These are typically for pollen types with just one dominant species in the flora and when the weather, in particular temperature, is stable during the pollination period. Based on s parameter of the Gaussian function, the dates of the main pollen season can be defined. In spite of the fact that seasonal curves are often characterised by positive skewness, the model based on the gamma distribution proved not to be very effective.     

Effects of weather conditions on selected airborne fungal spores in the southern part of the state of Enugu,Nigeria

A study of airborne fungal spore was carried out at nine locations in the southern part of the state of Enugu, Nigeria, from March 2005 to February 2006. The aim of the study was to ascertain the variations in selected fungal spore types at the sites owing to weather conditions. The variation in airborne fungal spores of 14 taxa was studied using modified Tauber pollen traps including Alternaria, Corynespora, Curvularia, Drechslera type, Endophragmiella, Botryodiplodia, Ganoderma, Gliomastrix, Nigrospora, Pithomyces, Spegazzinia, Sporidesmium, Tetraploa and Ustilago. The frequency of the spore types recorded showed considerable variation. The highest spore counts were recorded in July, June and October. The highest numbers of fungal spores were recorded during the rainy season (June–October) to early dry season (November–December). The peak of occurrence of most selected fungal spore types was July. The highest percentages of fungal spores were documented at the recording stations Mgbowo Junction, UNTH Ituku Ozalla and Oji River Express Junction. Spearman’s correlation analyses were performed for the monthly amounts of the fungal spore types and monthly meteorological factors. The numbers of Curvularia, Nigrospora and Sporidesmium was significantly correlated with relative humidity, while those of Endophragmiella, Pithomyces and Nigrospora were significantly correlated with temperature. A significant correlation was also found between the number of Nigrospora spores and light intensity and Sporidesmium spores and wind velocity. Relative humidity and temperature seem to be the most important weather conditions affecting the frequency of the selected spore types in the atmosphere.     

Airborne fungal spores in urban and rural environments in Poland

The concentrations of airborne fungal spores were measured during 2001–2002 in two sites in Poland—one in the city and the other in the countryside. The sites differed in habitat characteristics, such as urbanisation level, vegetation and microclimate. The aim of the study was to determine if, and in which way, land use type would affect spore occurrence. The volumetric method was used, and ten easily identifiable spore types were sampled and anyalysed: Alternaria, Botrytis, Cladosporium, Epiccocum, Ganoderma, Pithomyces, Polythrincium, Stemphylium, Torula and Drechslera. The season of spore occurrence was determined using the 90% method. The fungal spores studied were very frequent in the air (in most instances at a frequency higher than 50%). The most common spores were those of Cladosporium, with a frequency range of 83.1–90.5%. In both years the proportion of Cladosporium spores was statistically significantly higher in the city. In both 2001 and 2002 the total seasonal sum of all the spores was higher in the countryside than in the city as was the Seasonal Fungal Index (SFI) values and average concentrations of Botrytis, Ganoderma and Torula. These latter three genera are usually represented as pathogens of plants. The mean spore concentrations of most taxa were significantly higher in the rural environment. Correlation coefficients between daily concentrations at both sites for most of the taxa studied were significant, but with lower correlation values between variables. Such results indicate that the values from the sites are weakly interdependent. The study confirms that land use type may very likely have an impact on the course of spore occurrence, the mean daily concentrations of spores as well as SFI values.     

Some components of the air spora in Jamaica and their possible medical application

A knowledge of the pollen and fungal spores which comprise the air spora is useful as a preliminary approach to the problem of respiratory allergy. Therefore, this study of the qualitative and quantitative aspects of the air spora was done. Fungal spores were found to be numerically dominant, comprising 97.73% whilst pollen comprised 0.40% of the total material observed. A small number of types made up the majority of the fungal air spora, namely, Cladosporium, the Sporobolomycetaceae group, Diatrype, Glomerella, hyaline and coloured basidiospores, and septate fusiform spores. Seasonal periodicity studies on twenty-five fungal types showed that a high number of spores were trapped for sixteen during wet months, four during cooler months, and that five showed no seasonal trends. Mean diurnal periodicity studies for the year on the same twenty-five spore types showed that all had a maximum number of spores trapped at some time during the day. Investigation of the effect of rainfall on the numbers of spores released showed that the amount and duration of rainfall, the time of day rain occurs, and the length of the dry period preceding rain were of varying importance to particular spore types.     

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.     

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.     

An aerobiological study of pollen grains and fungal spores of Barcelona (Spain)

Summary A study of concentration of airborne pollen grains and fungal spores has been carried out in Barcelona (Spain) during 1989–90. The volumetric method of filtration, previously described for airborne pollen analysis (Suarez-Cervera and Seoane-Camba, 1983) has been used. In this case, the filters have also been cultivated in Czapecdox-agar, Sabouraud-agar and Sabouraud-agar with streptomycin for the identification of the fungal colonies. Analysis of the number of fungal spores growing on the filter shows that the maxima of colonies of spores developed in culture per m³ of air filtered, correspond to September–December. Pollen and spore concentrations start from November–December, reach a maximum in March–April and decline progressively until September–October. Therefore, in the city of Barcelona, the greatest concentration occurs in spring and the lowest in autumn.     

Fungal spores prevalent in the aerosol of the city of Caxias do Sul, Rio Grande do Sul, Brazil, over a 2-year period (2001–2002)

This study was carried out over a 2-year period (2001 and 2002) with the aim of identifying the fungal population in the aerosol of the Southern city of Caxias do Sul, RS, Brazil. Sampling was performed using Hirstȁ9s non-viable volumetric method. Our results show the presence of a large number of fungal spore types, a total of 41. Three groups were predominant: Deuteromycotina, Ascomycotina and Basidiomycotina. In 2001, Deuteromycotina taxa represented 44.61% of the total annual spore counts, with the largest concentration occurring in the fall (58,637 spores); in 2002, it represented 40.03% of the total annual spore counts, and the largest concentration was obtained in the summer (68,317 spores). Ascomycotina was present at the same level (24.5%) in both years of sampling, and the highest concentrations were found out in the summer (2001: 42,183 spores; 2002: 29,461 spores). Basidiomycotina represented 22.37% of the total annual spore counts in 2001, and 20.41% in 2002, with the largest concentrations found in the summer (2001: 35,988 spores; 2002: 30,212 spores). The most frequent fungi found during the study period were Cladosporium, Coprinus, Leptosphaeria, Aspergillus/Penicillium and Ganoderma. Permanent aerobiological monitoring would be necessary to detect associated environmental variations.     

Fusarium andDidymella-neglected spores in the air

Summary This paper reports about the occurence ofFusarium- andDidymella spores in the air of Essen/FRG. During the spore season 1990, the spore concentration was measured on several days with a volumetric pollen trap by hourly analysis. The calculated amount of spores per hour is compared to the data of a pluviometer and the values of the relative humidity during the same period.The occurence of both spore types in the air and high relative humidity (>80%) are correlated in a highly significant way (P<0.001). The dispersion of spores starts when rain begins or directly after the precipitation.Didymella reaches higher concentrations thanFusarium in the air (Maximum values:Didymella 30000 spores/m³,Fusarium only 800 spores/m³). During the emission of the spores the temperature varied between 10°C und 20°C degrees. Didymella andFusarium must be an important allergenic source in the outdoor area, because of their allergen-loaded biological aerosols. The question of providing well defined extracts ofDidymella exitialis is given to the pharmaceutical industry.     

An assessment of the air quality in indoor and outdoor air with reference to fungal spores and pollen grains in four working environments in Kerala, India

Qualitative and quantitative analyses of airborne fungal spores and pollen grains in four working environments (market, saw mill, poultry and cow sheds) in Thiruvananthapuram, the capital city of Kerala, India, were carried out for 2 years using Burkard Personal Slide Sampler and Andersen Two-Stage Sampler. Total spore concentration in these sites was always higher in indoor environments than in outdoor environments. Difference in concentration was not statistically significant in any of these work places except in saw mill (t test, p < 0.05). The highest spore concentration was recorded here followed by market, poultry and cow sheds. A total of 32 fungal spore types from indoor environments and 33 spore types from outdoor environments were recorded. Of them, 16 spore types were common to all the sites. Ameropsores, Cladosporium, other basidiospores, Ganoderma and Nigrospora were the dominant spore types in both indoor and outdoor environments. A total of 27 species of viable fungi from indoor and 24 species from outdoor environments were identified. Penicillium citrinum, Aspergillus flavus and Aspergillus niger were the most dominant viable fungi isolated. In contrast, total pollen concentration was always higher in outdoor environments than in indoor environments. Twenty-nine pollen types from indoor and 32 pollen types from outdoor were captured during the sampling. Poaceae, Cocos, Artocarpus, Amaranthus/Chenopodium and Tridax were the common and dominant pollen types observed in all the sites. Peak spore and pollen incidence were recorded during the late rainy and dry seasons (October–February) in both indoor and outdoor environments. The study revealed high prevalence of predominantly allergenic fungal spores and pollen grains in all the four work places. Workers/visitors are at potential risk of susceptibility to respiratory/allergic disorders.     

A long-term study of winter and early spring tree pollen in the Tulsa, Oklahoma atmosphere

Since 1986 the atmosphere in Tulsa, Oklahoma has been monitored for airborne pollen and spores with a Burkard 7-day spore trap situated on the roof of a building at The University of Tulsa. The present study specifically examined the early spring tree pollen season for several local taxa and the occurrence of pre-season pollen during December and January. Knowledge of the local pollen season will help identify the presence of out-of-season pollen and possible long distance transport (LDT) events. Average daily concentrations of airborne pollen for species ofBetula, Quercus, Ulmus, and Cupressaceae were determined for each year from 1987 to 1996. The data showed that during the early spring the precise pollination periods for these allergenic tree species are highly variable. There were considerable variations in start date, season length, peak concentration, date of peak, and cumulative season total. The start dates forUlmus, Betula, andQuercus varied by 30 days or more, while the early spring Cupressaceae pollen showed the least variation in start date (only 23 days). More research is needed to understand the mechanisms which govern the onset and magnitude of pollen release. Although several reports have documented episodes of long distance transport (LDT) of pollen, the actual contribution of out-of-season or out-of-region pollen to local air spora is poorly known. The current study also re-examined the LDT ofJuniperus ashei pollen in Oklahoma.Juniperus pollen appeared in the Tulsa atmosphere on 40% of the days in December and January with concentrations as high as 2400 pollen grains/m³ of air; however, no local populations ofJuniperus pollinate at this time of the year. High concentrations occurred on days with southerly winds suggesting thatJuniperus ashei populations in southern Oklahoma and Texas were the pollen source. Since no local pollen is present in the Tulsa atmosphere in December and January, this example of LDT has been easy to document.     

Performance of the Coriolis air sampler,a high-volume aerosol-collection system for quantification of airborne spores and pollen grains

The Coriolis δ air sampler manufactured by Bertin Technologies (France) is a continuous air sampler, dedicated to outdoor monitoring of airborne spores and pollen grains. This high-volume sampler is based on patented Coriolis technology delivering a liquid sample. The air is drawn into a conical vial in a whirling type motion using suction; particles are pulled against the wall by centrifugal force. Airborne particles are separated from the air and collected in a liquid medium. This innovative solution allows rapid analysis by several techniques including PCR assay and serological assay in order to measure the antigenicity/allergenicity of pollen grains and fungal spores. Also, traditional counting of pollen grains or taxa identification by optical microscopy can be done. A study has been carried out by the Health Protection Agency (HPA), Porton Down, UK, to measure the physical efficiency of the Coriolis air sampler. The physical efficiency of the sampler for collection of micro-organism-laden particles of various sizes has been compared with that of membrane filter samplers using the techniques described by ISO 14698-1. The Coriolis was operated simultaneously with membrane filter samplers in a controlled room where they were challenged with uniform-sized particles of different diameters containing bacterial spores. For the larger particle sizes, it was found that the physical efficiency of the Coriolis was 92% for 10-μm particles. The biological performance of the Coriolis in the collection of airborne fungal spores and pollen grains was evaluated in comparison with a Hirst spore trap (one-week tape-on-drum type sampler) which is one of the most frequently used traps in the measurement of outdoor pollen grain concentrations. The advantages and limitations of both technologies are discussed. The Coriolis was operated simultaneously with a Hirst spore trap in the sampling station of Réseau National de Surveillance Aérobiologique, France (RNSA); the pollen grain and fungal spore counts were analysed by optical microscopy. The pollen grain count m⁻³ collected was compared for both devices. The dispersion values were obtained and statistical analysis was carried out. This study shows that the Coriolis air sampler provided equivalent recovery of pollen grain and fungal spores compared with the volumetric trap standard method (not significantly different, W test, α = 0.05). Nowadays, the French-led project, acronym MONALISA, with financial support from the European Commission––Life-Environment (LIFE05 ENV/F/000068), is testing this innovative air sampler in order to measure the antigenicity/allergenicity of the main aeroallergen particles, i.e. Betula (birch), Poaceae (grasses), Parietaria (pellitory), Olea spp (olive tree), and Artemisia (mugwort) pollen grains, and Alternaria (fungal spores) to validate a new approach of monitoring instead of quantifying pollen grains by their morphology. The robustness and efficiency of the MONALISA system is being demonstrated at a national level throughout Europe in eight different countries with different bio-climatic and topography characteristics: France, UK, Finland, Poland, Spain, Portugal, Switzerland, and Italy.