Concentrations Of Alternaria Research Articles

The influence of agricultural land on the level of airborne Alternaria spores

Aim of the research was to investigate the impact of agricultural activity on the concentration of Alternaria spores.
 Materials and methods. The study was carried out at the Department of Medical Biology, Parasitology and Genetics of the ZSMPhU. Samples were collected using a 7-day volumetric sampler of the Hirst type, using the volumetric method. Samples were identified under a light microscope, and spore identification and counting were limited to genus levels. The relationship between seasonal Alternaria spore levels and harvest rates was analysed using Pearson's correlation method. The effect of meteorological conditions and agricultural activity on the daily concentration of Alternaria was analysed using stepwise correlation based on logarithmically transformed daily average spore counts. Classical leave-one-out cross-validation (LOOCV) was used to estimate the mean square error (MSE), associated with this model and Bayesian information criterion (BIC) was used to assess its accuracy.
 Results. Seasonal characteristics of Alternaria spores and agricultural activity in Zaporizhzhia and Dnipro regions were analysed. The connection of some seasonal and daily indicators with harvesting rates and meteorological conditions was determined. Two models with 5 and 9 parameters were found that best explain the dynamics of Alternaria spores.
 Conclusions. The most significant parameters positively correlated with Alternaria spore levels were temperature, pressure, westerly wind and wheat yield; relative humidity was negatively correlated

The contribution of aphids (Aphidoidea) to atmospheric concentrations of Alternaria and Cladosporium spores

Honeydew extracted by aphids serves as nutrient for the development of sooty moulds. Hypothetically, population dynamics of aphids should therefore have an effect on the airborne levels of the spores of fungi colonizing honeydew. In this study, the effects of seven aphid taxa on Alternaria and Cladosporium spore seasons (both pathogenic and allergenic fungi) were analysed on a total of 20-year-long dataset in Kecskemét (Hungary), Leicester (UK) and Poznań (Poland). Meteorological factors strongly effected both aphid and fungal populations. In most cases, a direct effect of weather on fungal levels were found. Direct effect of two aphid species, Acyrthosiphon pisum and Euceraphis punctipennis, on the atmospheric concentration of Alternaria spores was identified in Leicester and Poznań in June and July respectively. Other aphid species had secondary, but significant effects during other time periods. This suggests aphid population data can be informative in predicting airborne concentrations of Alternaria and Cladosporium spores.Graphical abstract

Airborne Alt a 1 Dynamic and Its Relationship with the Airborne Dynamics of Alternaria Conidia and Pleosporales Spores.

Fungal spores are universal atmospheric components associated to allergic reactions. Alternaria (Ascomycota) is considered the most allergenic spore taxa. Alt a 1 is the major allergen of Alternaria and is present also in other Pleosporales. In this study, standard Hirst-based sampling and analyzing methods for measuring spore daily concentrations of Alternaria, Curvularia, Drechslera-Helminthosporium, Epicoccum, Leptosphaeria, Pithomyces, Pleospora and Stemphylium (all included in the taxon Pleosporales) have been used as well as two high-volume samplers, Burkard Cyclone (2017) and MCV CAV-A/mb (2019–2020), and ELISA kits for measuring the allergen. The detection and quantification of Alt a 1 was only possible in the samples from the MCV sampler. Although Alt a 1 was better correlated with Alternaria spores than with Pleosporales spores, the three of them showed high correlations. It is shown that there is a high and significant correlation of Alt a 1 with temperature, a negative correlation with relative humidity and no correlation with precipitation. The aerobiological monitoring of these three elements ensures the best information for understanding the affectation to allergy sufferers, but, if this is not possible, as a minimum public health service aimed at the detection, treatment and prevention of allergies, the study of the airborne Alternaria spores should be ensured.

Temporal variations in fungal spores in Mardin city atmosphere, upper Mesopotamia, SE-Turkey

The present study aimed to determine the fungal spores and their concentrations in the atmosphere of Mardin (southeast Turkey) in 2014 and 2015 using the volumetric method. A total of 43 taxa, hyphal fragments, and single septate ascospores were identified by light microscopy. It was determined that the dominant fungal spores included Cladosporium (51.5%), Ustilaginales species spores (13.9%), Alternaria (6.9%), Pucciniales species spores (1.6%), Agrocybe (1.2%), Pleospora (1.1%) and hyphal fragments (15.5%). The highest atmospheric spore concentrations were observed in May and the lowest levels were determined in February in both years. Dry air spores constituted a significant ratio of the total count (73.9%) in the atmosphere of Mardin. There were significant positive correlations between atmospheric concentrations of Alternaria, Cladosporium, Ustilaginales, and Pucciniales spores and temperatures. There were significant negative correlations between airborne fungal spore concentrations and daily mean humidity. There was a significant negative correlation between Agrocybe spore concentrations and daily mean temperature and a significant positive correlation between the same and humidity and precipitation. No significant correlation was determined between the meteorological variables and Pleospora and Aspergillus/Penicillium spore concentrations.

Looking for a sustainable potato crop. Field assessment of early blight management

Potato crops are susceptible to numerous field diseases causing significant losses in the quality and tuber yield. Control measures have a negative impact in soil and water resources affecting also farmers’ health and food security. Hence, a more sustainable agriculture management is a need to preserve ecosystems. Therefore, the objective of this study was to evaluate the response of nine potato cultivars (Fleur Bleue, Frisia, Fontane, Louisa, Agria, Daifla, Red Pontiac, Kennebec and Desiree) against early blight using a Decision Support Systems (DSS) in a potato-producing area from Northwest Spain. The experimental design was established using control plots and sprayed plots with fungicide according to a disease risk model adapted to the geographical region (DSS plots). Disease rating and severity were evaluated in field from the appearance of the first symptoms to final of senescence and the area under disease progress curve (AUDPC and r-AUDPC) was calculated. Aerobiological monitoring of main Alternaria species responsible potato early blight (Alternaria solani and Alternaria alternata) and the most vulnerable phenological stages were also considered. The susceptibility of the potato cultivars was analyzed based on the weather, severity of the disease and tuber yields. Specifically, temperature and leaf wetness were the meteorological variables that most influenced on the concentration of Alternaria. Conidia accounted for the previous week was the variable that most influenced in development of symptoms measured by AUDPC in natural conditions. Yields in the cultivars of DSS plots were higher than in control plots. Therefore, alternative pest management strategies, and specifically, Decision Support Systems for pest assessment are crucial for sustainable potato production. In this sense, the integration of particular information on disease resistance of commercial cultivars, phenological development of plant, or fungal particles surrounding the crop atmosphere could support these systems for better adjustment without compromising tuber yield and environment.

Modification of the TOMCAST Model with Aerobiological Data for Management of Potato Early Blight

The present study focuses on establishing thresholds of weather variables for predict early blight in potato crops. For this, the TOMCAST model was adjusted using weather variables and Alternaria conidia levels (mainly A. solani and A. alternata) during six growing seasons in A Limia (Northwest Spain). TOMCAST for the effective management of early blight considers leaf wetness and air temperature to calculate daily severity values (DSVs). Spearman correlations between temperature (minimum and average), mean temperature during leaf wetness period and Alternaria concentration showed the highest positive significant coefficients (0.386, 0.230 and 0.372, respectively; p < 0.01). Specifically, Alternaria levels higher than 50 spores/m3 were found the days with air mean temperature above 18 °C, more than 7 h of leaf wetness. Leaf wetness was decisive to estimate the concentration of Alternaria, resulting in a significant linear regression model (R2 = 0.41; p < 0.001). TOMCAST was adapted to the area, considering 10 °C the minimum threshold for the mean value of temperature during the wet period and 10–15 accumulated disease severity values (DSV). Using TOMCAST, it was possible to predict the first Alternaria peak in most of potato growing seasons. Combining aerobiological and meteorological data to control fungal diseases during crops are a useful tool for sustainable agriculture.

Seasonal Dynamics of Alternaria during the Potato Growing Cycle and the Influence of Weather on the Early Blight Disease in North-West Spain

Early blight caused mainly by Alternaria solani Soraeur and Alternaria alternata (Fr.) Keissl is one of the main diseases of potato. To improve forecasting of disease risk and to provide useful tools for a good decision support system, knowledge about the influence of environmental conditions on the Alternaria species, is necessary. The pattern distribution of the Alternaria spores during eight potato growing cycles in “A Limia” (north-west Spain), and the relationships between Alternaria levels and meteorological parameters were analyzed. Also, the phenology of the potato plants and the meteorological conditions during the study were monitored. Higher Alternaria peaks were found during plant senescence. Nevertheless, extremely high levels can appear starting the plant flowering, when the disease is more destructive. Statistical analysis showed a close relationship between temperature and relative humidity with the concentration of Alternaria in the air. Higher Alternaria levels were observed with a mean temperature above 20 °C and a mean relative humidity below 70%. It is also important to highlight that lower temperature and higher relative humidity during the night, favours the formation of Alternaria spores during the day. The present study showed how differences in weather can be related with the presence of Alternaria spores in the atmosphere of potato crop, and how climate change could affect the development of this agricultural crop. If Spain continues to experience increases in temperature events, longer duration and increasing intensity of early blight epidemics in potato crops are expected in future years.

Interrupted Wet Period (IWP) to Forecast the Aerial Alternaria in Potato Crops of A Limia (Spain)

Potato early blight caused by Alternaria solani generates significant economic losses in crops worldwide. Forecasting the risk of infection on crops is indispensable for the management of the fungal disease, ensuring maximum economic benefit but with minimal environmental impact. This work aimed to calculate the interrupted wet periods (IWP) according to the climate conditions of A Limia (Northwest of Spain) to optimize the prediction against early blight in potatoes. The study was performed during nine crop cycles. The relative hourly humidity and Alternaria concentration in the crop environment were taken into account. Alternaria levels were monitored by aerobiological techniques using a LANZONI VPPS-2000 volumetric trap. The relationships between weather conditions and airborne Alternaria concentration were statistically analyzed using Spearman correlations. To establish the effectiveness of wetness periods, the first important Alternaria peak was taken into account in each crop cycle (with a concentration greater than 70 spores/m3). Considering the six interrupted wet periods of the system, it was possible to predict the first peak of Alternaria several days in advance (between 6 and 38 days), except in 2007 and 2018. Automated systems to predict the initiation of early blight in potato crop, such as interrupted wet periods, could be an effective basis for developing decision support systems. The incorporation of aerobiological data for the calculation of interrupted wet periods improved the results of this system.

The influence of meteorological parameters on Alternaria and Cladosporium fungal spore concentrations in Beja (Southern Portugal): preliminary results

Introduction Fungal spores constitute an important fraction of bioaerosols in the atmosphere. Objectives To analyse the content of Alternaria and Cladosporium spores in the atmosphere of Beja and the effect of meteorological conditions on their concentrations. Methodology The daily and hourly data of Alternaria and Cladosporium fungal spores concentration in the atmosphere of Beja were monitored from April 12, 2012 to July 30, 2014, based on the Portuguese Aerobiology Network methodology. The influence of meteorological conditions on the studied types of fungal spore concentrations was assessed through Spearman’s correlation analysis. Results During the study period, 20,741 Alternaria spores and 320,862 Cladosporium spores were counted. In 2013, there were 5,822 Alternaria spores and 123,864 Cladosporium spores. The absolute maximum concentrations of Alternaria and Cladosporium spores were recorded on November 8, 2013, with 211 and 1301 spores/m3, respectively. Temperature, insolation and wind direction parameters showed a positive correlation with Alternaria and Cladosporium spore levels, while relative humidity and precipitation presented a negative correlation, which is statistically significant. Wind speed only showed a statistically significant positive correlation in terms of Alternaria spore levels. Conclusion Alternaria and Cladosporium spores are present in the atmospheric air of Beja throughout the year, with the highest concentration period occurring during spring and autumn. There was a clear effect of meteorological parameters on airborne concentrations of these fungal spores.

Visual, instrumental, mycological and mycotoxicological characterization of wheat inoculated with and protected against Alternaria spp.

The aim of this work was to characterize visual properties, instrumentally measured colour properties, field fungi presence and Alternaria toxins levels in wheat samples grown under conditions aimed at inhibition and stimulation of wheat infection with fungi from the Alternaria genus. Experiment was carried out on the wheat treated by fungicide and wheat inoculated by Alternaria spp., while non treated wheat was used as a control. Statistically significant difference was observed between all three treatments using visual scale. Protected wheat samples were significantly different from other samples in terms of all measured colour parameters while inoculated and control wheat samples were significantly different in terms of lightness and dominant wavelength. Identification of field fungi in the all examined wheat samples showed that the dominant mycotoxigenic fungus was Alternaria spp., followed by Fusarium spp. The content of Alternaria toxins in samples of wheat hulls and dehulled kernels point out at higher concentrations of Alternaria toxins in hulls than in dehulled kernels.

A 10-year study of Alternaria and Cladosporium in two Polish cities (Szczecin and Cracow) and relationship with the meteorological parameters.

Alternaria and Cladosporium spores belong to the most frequent and allergenic particles in bioaerosol in the temperate climate. The investigation of Alternaria and Cladosporium spore concentrations was performed in two cities in Poland, Szczecin and Cracow, in 2004–2013. The meteorological parameters taken to assess their impact on fungal spores were average, maximum and minimum temperature, relative humidity and average wind velocity. In order to reveal whether changes in dynamics of spore seasons are driven by meteorological conditions, ordination methods were applied. Canonical correspondence analysis was used to explore redundancy among the predictors (meteorological parameters). Prior to ordination analyses, the data were log(x)-transformed. Concentrations of Alternaria and Cladosporium spores were significantly higher in Szczecin comparing to Cracow, but it was also observed the decreasing trend in the spore concentrations in Szczecin. As regards temperature, it was higher in Cracow and was still increasing in the studied years. Relative humidity and wind velocity were significantly lower in Cracow. In Szczecin meteorological conditions did not explain changes in spore season characteristics (insignificant redundancy analysis models), while in Cracow’s redundancy analysis models indicated that spore season parameters were in over 40 % determined by meteorological conditions, mainly air temperature and wind velocity. If they increase, the peak value, total number of spores and their average concentrations in a season will also increase.

Atmospheric concentrations of Alternaria, Cladosporium, Ganoderma and Didymella spores monitored in Cork (Ireland) and Worcester (England) during the summer of 2010

This study represents the first international intercomparison of fungal spore observations since 1990, focusing on atmospheric concentrations of Alternaria, Cladosporium, Ganoderma and Didymella spores. The campaigns were performed at sites located in Cork (Ireland) and Worcester (England) during summer 2010. Observations were made using Hirst-type volumetric spore traps and corresponding optical identification at the genus level by microscope. The measurements at both sites (including meteorological parameters) were compared and contrasted. The relationships between the fungal spore concentrations with selected meteorological parameters were investigated using statistical methods and multivariate regression trees (MRT). The results showed high correlations between the two sites with respect to daily variations. Statistically significant higher spore concentrations for Alternaria, Cladosporium and Ganoderma were monitored at the Worcester site. This result was most likely due to the differences in precipitation and local fungal spore sources at the two sites. Alternaria and Cladosporium reached their maxima a month earlier in Cork than in Worcester, and Didymella with Ganoderma peaked simultaneously with similar diurnal trends found for all the investigated spore types. MRT analysis helped to determine threshold values of the meteorological parameters that exerted most influence on the presence of spores: they were found to vary at the two sites. Our results suggest that the aeromycological profile is quite uniform over the British Isles, but a description of bioaerosols with respect to overall load and daily concentration can be quite diverse although the geographical difference between sites is relatively small. These variations in the concentrations therefore need to be explored at the national level.

Variation in Airborne Fungal Spore Concentrations in Four Different Microclimate Regions in Romania

Airborne fungal counts and types were examined in four regions from Romania. The aim of our study was to determine the concentrations of Alternaria, Cladosporium, Drechslera-type, Epicoccum and Nigrospora atmospheric fungal spores in urban areas: Braşov, Bucharest, Cluj-Napoca and Timişoara. Other objective of this study was to examine the relationships between atmospheric fungal spores and pollen. Few studies have confirmed the high frequency and concentrations for some of these spore types in Romania. The sampling sites differed in habitat characteristics, such as vegetation and microclimate. Airborne spores’ sampling was carried out using the Lanzoni volumetric sampler and during August 2008. The totals of airborne spores recorded in this study show a considerable variation. Cladosporium and Alternaria have been identified as the most abundant and frequent fungal aeroallergens in Timişoara and Bucharest. Drechslera-type, Epicoccum, and Nigrospora had very low values of spore count in all sites. Observations show that seven types of pollen appear regularly and few of these are in great abundance. Fungi are present in the air in concentrations considerably in excess of that of pollen grains. Ambrosia artemisiifolia is the most important pollen allergen in all of the sampled areas discussed here, especially in western country (Timişoara).

Combining real-time PCR and next-generation DNA sequencing to provide quantitative comparisons of fungal aerosol populations

We examined fungal communities associated with the PM10 mass of Rehovot, Israel outdoor air samples collected in the spring and fall seasons. Fungal communities were described by 454 pyrosequencing of the internal transcribed spacer (ITS) region of the fungal ribosomal RNA encoding gene. To allow for a more quantitative comparison of fungal exposure in humans, the relative abundance values of specific taxa were transformed to absolute concentrations through multiplying these values by the sample's total fungal spore concentration (derived from universal fungal qPCR). Next, the sequencing-based absolute concentrations for Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, and Penicillium/Aspergillus spp. were compared to taxon-specific qPCR concentrations for A. alternata, C. cladosporioides, E. nigrum, and Penicillium/Aspergillus spp. derived from the same spring and fall aerosol samples. Results of these comparisons showed that the absolute concentration values generated from pyrosequencing were strongly associated with the concentration values derived from taxon-specific qPCR (for all four species, p < 0.005, all R > 0.70). The correlation coefficients were greater for species present in higher concentrations. Our microbial aerosol population analyses demonstrated that fungal diversity (number of fungal operational taxonomic units) was higher in the spring compared to the fall (p = 0.02), and principal coordinate analysis showed distinct seasonal differences in taxa distribution (ANOSIM p = 0.004). Among genera containing allergenic and/or pathogenic species, the absolute concentrations of Alternaria, Aspergillus, Fusarium, and Cladosporium were greater in the fall, while Cryptococcus, Penicillium, and Ulocladium concentrations were greater in the spring. The transformation of pyrosequencing fungal population relative abundance data to absolute concentrations can improve next-generation DNA sequencing-based quantitative aerosol exposure assessment.

Wheeze in infancy: protection associated with yeasts in house dust contrasts with increased risk associated with yeasts in indoor air and other fungal taxa

While fungal exposures are assumed to provoke wheeze through irritant or allergenic mechanisms, little is known about the differential effects of indoor and outdoor fungi on early-life wheeze. In a Boston prospective birth cohort of 499 at-risk infants, culturable fungi in bedroom air and dust and outdoor air were measured at the age of 2-3 months. Wheeze was determined using bimonthly telephone questionnaires. Odds ratios were estimated for an interquartile increase in fungal natural log-transformed concentrations, adjusting for predictors of wheeze and potential confounders. Increased odds of 'any wheeze' (≥1 vs 0 episodes) by age one were positively associated with indoor dust Alternaria [odds ratio (OR) = 1.83; 95% confidence interval (CI), 1.07-3.14], Penicillium [OR = 1.18; (0.98-1.43)], and Cladosporium [OR = 1.47; (1.16-1.85)]; indoor air Penicillium [OR = 1.26; (0.92-1.74)]; and outdoor air Cladosporium [OR = 1.68; (1.04-2.72)]. In contrast, indoor dust yeasts were protective [OR = 0.78; (0.66-0.93)]. 'Frequent wheeze' (≥2 vs <2 episodes) by age one was borderline associated with dust yeasts [OR = 0.86; (0.70-1.04)] and indoor air yeasts [OR = 1.53; (0.93-2.53)]. Alternaria concentration was associated with any wheeze for children with maternal mold sensitization [OR = 9.16; (1.37-61.22)], but not for those without maternal mold sensitization [OR = 1.32; (0.79-2.20)]. While wheeze rates were higher with exposures to fungal taxa considered to be irritant or allergenic in sensitive subjects, yeasts in the home had a strong protective association with wheeze in infancy. Molecular microbiologic studies may elucidate specific components of innate microbiologic stimulants that lead to contrasting effects on wheeze development.

Effect of airborne Alternaria conidia, ozone exposure, PM10 and weather on emergency visits for asthma in school-age children in Kolkata city, India

Alternaria is one of the important allergenic fungal spores having special role in childhood asthma. Aerodynamic particle of <10 μm diameter (PM10) and ozone exacerbate respiratory conditions including asthma. There is no documentation determining the role of airborne concentration of Alternaria conidia, pollutants like PM10 and ozone and weather on school-age (5–18 years) children causing life-threatening episodes requiring emergency hospitalization for asthma in the megacity of Kolkata, Eastern India. We examined the relationship of daily hospitalization for asthma in school-age children and daily concentration of outdoor Alternaria conidia, ozone, PM10 and weather parameters in the atmosphere of Kolkata during 2010 using nonparametric generalized additive model (GAM). After a baseline survey (2008–2009), asthma hospitalization data for school-age children (based on case history and symptom-medication) were collected from two important city hospitals near study area in 2010. Daily Alternaria concentration was recorded using Burkard volumetric sampler. Its allergenic potential was confirmed by skin reactivity. Ozone and PM10 concentration data were collected from West Bengal Pollution Control Board. The daily time series analyses of data were performed using GAM. There are two peak seasons of asthma hospitalization, one in spring-early summer (end of March to mid April) and other in autumn (mid September–October). In GAM analyses, Alternaria conidia, ozone and PM10 were found to be significant both in spline and LOcal regrESSion smoothing method. Airborne Alternaria conidia, ozone and PM10 in the city of Kolkata are found to have effect on school-age children with asthma and appear responsible for severe attacks leading to hospitalization.

End‐Organ Testing for Allergic Rhinitis with Fungi Is Poorly Correlated with Fungal Sensitivity

To evaluate optical rhinometry (ORM) using nasal provocation testing (NPT) as an objective tool to diagnose fungal allergic rhinitis (AR). Prospective. Tertiary academic center. We prospectively enrolled healthy controls (HCs) and subjects with a clinical history of AR and positive skin prick test to Alternaria or Aspergillus antigens. Baseline measurements with an optical and acoustic rhinometer (AcR) were taken, and all subjects underwent NPT with increasing concentrations of Alternaria and then Aspergillus in each nasal cavity. Optical density (OD), nasal mean cross-sectional area (MCA), visual analog scale (VAS), and nasal allergen provocation scale (NAP) were measured after each provocation. A NAP score ≥ 3 was considered positive. Receiver operating characteristic (ROC) curve analysis was performed on measured parameters. Eleven HCs and 11 AR subjects were enrolled. Of the 8 AR patients with an Alternaria-positive skin test, 50% had a positive NAP score (4/8) vs 0% in HCs (0/11, P = .01). Although VAS could differentiate Alternaria-sensitive patients from controls, change in OD and MCA could not. Of the 7 skin test-positive Aspergillus patients, 43% had a positive NAP score (3/7) vs 0% in HCs (0/11, P = .02). The VAS and change in OD and MCA did not differentiate Aspergillus-sensitive patients from controls. In this study, fungal antigens caused irritation but did not elicit early phase changes in nasal patency or blood flow in fungal-sensitive AR patients. The poor correlation of skin testing and objective nasal response to fungi argues against a pure IgE-mediated immune response in the nasal cavity.

Changes in concentration of Alternaria and Cladosporium spores during summer storms

Fungal spores are known to cause allergic sensitization. Recent studies reported a strong association between asthma symptoms and thunderstorms that could be explained by an increase in airborne fungal spore concentrations. Just before and during thunderstorms the values of meteorological parameters rapidly change. Therefore, the goal of this study was to create a predictive model for hourly concentrations of atmospheric Alternaria and Cladosporium spores on days with summer storms in Szczecin (Poland) based on meteorological conditions. For this study we have chosen all days of June, July and August (2004–2009) with convective thunderstorms. There were statistically significant relationships between spore concentration and meteorological parameters: positive for air temperature and ozone content while negative for relative humidity. In general, before a thunderstorm, air temperature and ozone concentration increased, which was accompanied by a considerable increase in spore concentration. During and after a storm, relative humidity increased while both air temperature ozone concentration along with spore concentrations decreased. Artificial neural networks (ANN) were used to assess forecasting possibilities. Good performance of ANN models in this study suggest that it is possible to predict spore concentrations from meteorological variables 2 h in advance and, thus, warn people with spore-related asthma symptoms about the increasing abundance of airborne fungi on days with storms.

Identity of the fungal species present in the homes of asthmatic children

Fungal exposures are believed to play an important role in the development of asthma and atopy, accounting for increased asthmatic symptoms and severe asthma exacerbation. Indoor fungal species vary both in taxa and concentration in different residences and in different regions. We explored the fungal species spectrum in 88 homes with at least one asthmatic child in the Middle West region of the United States mostly during late spring and fall season in comparison with 85 homes that did not contain an asthmatic child during flu season. The average fungal spore counts per cubic metre of air in the bedroom of the enrolled child, the main living spaces and outdoor environments, and the culturable fungal colony-forming units per cubic metre of air samples in the main living space from each home were measured. The results indicated that Cladosporium, Penicillium, Aspergillus, Basidiospores, Epicoccum and Pithomyces were found in more asthmatic homes than in homes without an asthmatic child or existed in higher concentration in asthmatic homes than in homes without an asthmatic child even after adjusting outdoor spore concentration. The results for culturable fungal species confirmed most of these findings even after adjusting for seasonal factors. Although Alternaria was commonly found in both kinds of homes, there was no significant difference in detection rate or concentration of Alternaria between asthmatic homes and homes without an asthmatic child by either spore counting or culturable airborne detection. Since many allergens have been identified in these fungal species, identifying and controlling these fungal species in asthmatic homes might be expected to improve asthma care and benefit asthmatic children.

Intradiurnal periodicity of fungal spore concentrations (Alternaria, Botrytis, Cladosporium, Didymella, Ganoderma) in Cracow, Poland

Aerobiological monitoring enables the definition of seasonal fungal spore concentrations and also intradiurnal time when the highest concentrations of spores could cause or increase allergy symptoms. These data are useful to estimate symptoms of disease, duration of infection and how advanced the illness is in people suffering from fungal allergens. The aim of the study was to compare the concentrations of fungal spores (Alternaria, Botrytis, Cladosporium, Didymella, Ganoderma) during dry and rainy periods and to analyse their intradiurnal changes. Average daily spore concentrations in dry and rainy periods were compared, using z test, separately for each taxon, season and for a combined 3-year period. Intradiurnal periodicity of fungal spore concentrations was analysed on the basis of three complementary diagrams. These spore concentrations were presented using three curves for all, dry and rainy days in 1997–1999 (April–November). The spore percentage in particular hours was normalized in relation to the daily spore sum accepted as 100%. Two further diagrams enabled the more precise analysis of the highest concentrations in dry days. Daily Botrytis and Cladosporium spore concentrations did not show significant differences between dry and rainy periods. In the case of Didymella and Ganoderma spore concentrations, there were no significant differences between both weather types in the single years, although there was a significant difference when a 3-year period was considered. The differences between daily concentrations of Alternaria spores in dry and rainy periods occurred in 1997 and in a 3-year period. Intradiurnal periodicity of spore concentrations was different for ‘dry’ and ‘wet’ fungal spores. Dry spores are released from the spore-producing parts of the fungus under conditions of decreasing humidity and increasing airflow. Examples of dry spores are those from Alternaria, Cladosporium and Botrytis. Wet spores, such as those from many Ascomycetes (Didymella) and Basidiomycetes (Ganoderma), are released into the atmosphere by processes related to humidity conditions or rain. The highest concentrations of ‘dry’ spores were observed early in the afternoon, while highest values of ‘wet’ spore concentrations occurred in the predawn hours. Statistically non-significant differences between daily spore concentrations in dry and rainy periods of single seasons were found except for Alternaria. Statistically significant differences could occur when the studied period was longer than one season (Alternaria, Didymella, Ganoderma). The highest concentrations of Alternaria, Botrytis and Cladosporium spores were recorded at noon and early in the afternoon. Concentrations of Didymella and Ganoderma spores were highest in the predawn hours.