Alternaria Spores Research Articles

Airborne Alternaria Spores: 70 Annual Records in Northwestern Spain.

This study presents data on the concentration of Alternaria spores in the atmosphere of the northwestern Iberian Peninsula. A non-viable volumetric method was used to collect the samples, resulting in a database of 70 annual. When the annual averages for each locality are calculated, Ourense stands out with 2152 spores/m3, followed by Vigo and Lugo, while Santiago de Compostela recorded the lowest concentrations. Focusing on the total data for each locality, the main sporulation period started in May and ended in October in all localities, centered on a single phase, with an earlier onset and longer duration in Ourense and Vigo. The number of days with concentrations in excess of 100 spores/m3 was very low in Santiago de Compostela, Ourense, and Vigo and null in Lugo. Temperature was the meteorological parameter for which the highest statistical correlation was obtained in all locations, being favorable to the concentration of spores in the air. Temperature ranges favorable to the presence of airborne spores in the study area ranged from 25.5 to 31.2 °C. Based on the analysis of the data collected, it is concluded that Alternaria spore concentrations are low throughout most of the year.

Study on the Effectiveness of a Copper Electrostatic Filtration System "Aerok 1.0" for Air Disinfection.

Bioaerosols can represent a danger to health. During SARS-CoV-2 pandemic, portable devices were used in different environments and considered a valuable prevention tool. This study has evaluated the effectiveness of the air treatment device "AEROK 1.0®" in reducing microbial, particulate, and pollen airborne contamination indoors, during normal activity. In an administrative room, airborne microbial contamination was measured using active (DUOSAS 360 and MD8) and passive sampling; a particle counter was used to evaluate particle concentrations; a Hirst-type pollen trap was used to assess airborne pollen and Alternaria spores. Statistical analysis was performed using SPSS 26.0; p values < 0.05 were considered statistically significant. The airborne bacterial contamination assessed by the two different samplers decreased by 56% and 69%, respectively. The airborne bacterial contamination assessed by passive sampling decreased by 44%. For fungi, the reduction was 39% by active sampling. Airborne particles (diameters ≥ 1.0, 2.0 μm) and the ratio of indoor/outdoor concentrations of total pollen and Alternaria spp. spores significantly decreased. The results highlight the effectiveness of AEROK 1.0® in reducing airborne contamination. The approach carried out represents a contribution to the definition of a standardized model for evaluating the effectiveness of devices to be used for air disinfection.

Grain Discolouration Disease Complex of Rice: Assessment and Management of Infested Grains Using Fungicides

Rice grain discoloration complex disease is threatening the crop all over the world and its of great importance because it leads to quality loss at harvest. So the present study was carried out to identify different fungi associated with this complex disease and management of infested rice seeds though fungicides. For this purpose, discolored grain samples were collected and different fungi were isolated. Identification of isolated fungi was done on the basis of their morphological characters and purified culture of each fungus was prepared. Pathogenecity test was carried out in-vitro and in-vivo using the percentage incidence calculation to confirm the involvement of fungi. Statistical results illustrated that the homogenous mixture of spore suspension contains fungal spores of Fusarium spp, Tricoderma, Aspergillus flavus, Aspergilus niger, Helmithosporium, Cercospora, Alternaria, Bipolaris and Curvularia of rice proven most lethal in showing the maximum symptoms in-vitro and in-vivo. Statistical data for seed germination exhibited that Carbendazim and Diathene-M45 were comparatively better and improved percentage seed germination up to considerable levels followed by Redomil, Topsin-M and Cordate respectively.

Identifying key environmental factors to model Alt a 1 airborne allergen presence and variation

Fungal spores, commonly found in the atmosphere, can trigger important respiratory disorders. The glycoprotein Alt a 1 is the major allergen present in conidia of the genus Alternaria and has a high clinical relevance for people sensitized to fungi. Exposure to this allergen has been traditionally assessed by aerobiological spore counts, although this does not always offer an accurate estimate of airborne allergen load. This study aims to pinpoint the key factors that explain the presence and variation of Alt a 1 concentration in the atmosphere in order to establish exposure risk periods and improve forecasting models. Alternaria spores were sampled using a Hirst-type volumetric sampler over a five-year period. The allergenic fraction from the bioaerosol was collected using a low-volume cyclone sampler and Alt a 1 quantified by Enzyme-Linked ImmunoSorbent Assay. A cluster analysis was executed in order to group days with similar environmental features and then analyze days with the presence of the allergen in each of them. Subsequently, a quadratic discriminant analysis was performed to evaluate if the selected variables can predict days with high Alt a 1 load. The results indicate that higher temperatures and absolute humidity favor the presence of Alt a 1 in the atmosphere, while time of precipitation is related to days without allergen. Moreover, using the selected parameters, the quadratic discriminant analysis to predict days with allergen showed an accuracy rate between 67 % and 85 %. The mismatch between daily airborne concentration of Alternaria spores and allergen load can be explained by the greater contribution of medium-to-long distance transport of the allergen from the major emission sources as compared with spores. Results highlight the importance of conducting aeroallergen quantification studies together with spore counts to improve the forecasting models of allergy risk, especially for fungal spores.

Carvacrol Treatment Reduces Decay and Maintains the Postharvest Quality of Red Grape Fruits (Vitis vinifera L.) Inoculated with Alternaria alternata.

In this study, we isolated and identified pathogenic fungi from the naturally occurring fruits of red grapes, studied their biological characteristics, screened fifteen essential oil components to find the best natural antibacterial agent with the strongest inhibitory effect, and then compared the incidence of postharvest diseases and storage potential of red grapes treated with two concentrations (0.5 EC50/EC50) of essential oil components (inoculated with pathogenic fungi) during storage for 12 d at room temperature. In our research, Alternaria alternata was the primary pathogenic fungus of red grapes. Specifically, red grapes became infected which caused diseases, regardless of whether they were inoculated with Alternaria alternata in an injured or uninjured state. Our findings demonstrated that the following conditions were ideal for Alternaria alternata mycelial development and spore germination: BSA medium, D-maltose, ammonium nitrate, 28 °C, pH 6, and exposure to light. For the best Alternaria alternata spore production, OA medium, mannitol, urea, 34 °C, pH 9, and dark conditions were advised. Furthermore, with an EC50 value of 36.71 μg/mL, carvacrol demonstrated the highest inhibitory impact on Alternaria alternata among the 15 components of essential oils. In the meantime, treatment with EC50 concentration of carvacrol was found to be more effective than 0.5 EC50 concentration for controlling Alternaria alternata-induced decay disease of red grapes. The fruits exhibited remarkable improvements in the activity of defense-related enzymes, preservation of the greatest hardness and total soluble solids content, reduction in membrane lipid peroxidation in the peel, and preservation of the structural integrity of peel cells. Consequently, carvacrol was able to prevent the Alternaria alternata infestation disease that affects red grapes, and its EC50 concentration produced the greatest outcomes.

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.&#x0D; 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.&#x0D; 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.&#x0D; Conclusions. The most significant parameters positively correlated with Alternaria spore levels were temperature, pressure, westerly wind and wheat yield; relative humidity was negatively correlated

Outdoor Alternaria and Cladosporium spores and acute asthma.

Outdoor Alternaria and Cladosporium spores are ubiquitous. Few studies have assessed their impact on asthma hospitalizations providing conflicting results, mainly focused on vulnerable paediatric populations. We aimed to study the impact of outdoor Alternaria and Cladosporium concentrations on acute hospitalizations in the Capital Region of Denmark. This is a bi-directional case-crossover study with 26 years of national registry data at individual level on acute asthma hospitalizations and daily average data on Alternaria and Cladosporium, pollen (Artemisia, Poaceae), maximal temperature, and air pollution. Conditional logistic regression models were applied to assess the associations. Concentration quartiles at lag 0 were used for categorizing the exposure. For lags 0-2, the odds of hospitalization were significantly higher for both Alternaria and Cladosporium at concentration quartile 2-4 compared with quartile 1. When stratified for age and sex, odds of hospitalization at Alternaria quartiles 2-4 were significantly higher in males below 40 years at lag 0-2, and at lag 0 in females (18-30 years), while quartiles 2-4 of Cladosporium concentrations were associated with significantly higher odds in boys (0-17 years) at lag 1-3, males (18-39 years) at lag 0-1, females (18-39 years) at lag 1-2, males (40-64 years) at lag 0-2, females (40-64 years) at lag 0 and 2, in seniors (65+ years) male at lag 1-2 and female at lag 0-1. The effect of Alternaria varied significantly depending on the level of Cladosporium (p < .0001). Ambient Alternaria and Cladosporium spores can induce asthma hospitalizations. Males are more susceptible to both genera. Males and females under age 40 years are more susceptible to Alternaria.

Co-exposure to highly allergenic airborne pollen and fungal spores in Europe

The study is aimed at determining the potential spatiotemporal risk of the co-occurrence of airborne pollen and fungal spores high concentrations in different bio-climatic zones in Europe. Birch, grass, mugwort, ragweed, olive pollen and Alternaria and Cladosporium fungal spores were investigated at 16 sites in Europe, in 2005–2019. In Central and northern Europe, pollen and fungal spore seasons mainly overlap in June and July, while in South Europe, the highest pollen concentrations occur frequently outside of the spore seasons. In the coldest climate, no allergy thresholds were exceeded simultaneously by two spore or pollen taxa, while in the warmest climate most of the days with at least two pollen taxa exceeding threshold values were observed. The annual air temperature amplitude seems to be the main bioclimatic factor influencing the accumulation of days in which Alternaria and Cladosporium spores simultaneously exceed allergy thresholds. The phenomenon of co-occurrence of airborne allergen concentrations gets increasingly common in Europe and is proposed to be present on other continents, especially in temperate climate.

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

Potential Biocontrol Agents of Corn Tar Spot Disease Isolated from Overwintered Phyllachora maydis Stromata.

Tar spot disease in corn, caused by Phyllachora maydis, can reduce grain yield by limiting the total photosynthetic area in leaves. Stromata of P. maydis are long-term survival structures that can germinate and release spores in a gelatinous matrix in the spring, which are thought to serve as inoculum in newly planted fields. In this study, overwintered stromata in corn leaves were collected in Central Illinois, surface sterilized, and caged on water agar medium. Fungi and bacteria were collected from the surface of stromata that did not germinate and showed microbial growth. Twenty-two Alternaria isolates and three Cladosporium isolates were collected. Eighteen bacteria, most frequently Pseudomonas and Pantoea species, were also isolated. Spores of Alternaria, Cladosporium, and Gliocladium catenulatum (formulated as a commercial biofungicide) reduced the number of stromata that germinated compared to control untreated stromata. These data suggest that fungi collected from overwintered tar spot stromata can serve as biological control organisms against tar spot disease.

Going over Fungal Allergy: Alternaria alternata and Its Allergens

Fungal allergy is the third most frequent cause of respiratory pathologies and the most related to a poor prognosis of asthma. The genera Alternaria and Cladosporium are the most frequently associated with allergic respiratory diseases, with Alternaria being the one with the highest prevalence of sensitization. Alternaria alternata is an outdoor fungus whose spores disseminate in warm and dry air, reaching peak levels in temperate summers. Alternaria can also be found in damp and insufficiently ventilated houses, causing what is known as sick building syndrome. Thus, exposure to fungal allergens can occur outdoors and indoors. However, not only spores but also fungal fragments contain detectable amounts of allergens and may function as aeroallergenic sources. Allergenic extracts of Alternaria hyphae and spores are still in use for the diagnosis and treatment of allergic diseases but are variable and insufficiently standardised, as they are often a random mixture of allergenic ingredients and casual impurities. Thus, diagnosis of fungal allergy has been difficult, and knowledge about new fungal allergens is stuck. The number of allergens described in Fungi remains almost constant while new allergens are being found in the Plantae and Animalia kingdoms. Given Alt a 1 is not the unique Alternaria allergen eliciting allergy symptoms, component-resolved diagnosis strategies should be applied to diagnose fungal allergy. To date, twelve A. alternata allergens are accepted in the WHO/IUIS Allergen Nomenclature Subcommittee, many of them are enzymes: Alt a 4 (disulfide isomerase), Alt a 6 (enolase), Alt a 8 (mannitol de-hydrogenase), Alt a 10 (aldehyde dehydrogenase), Alt a 13 (glutathione-S-transferase) and Alt a MnSOD (Mn superoxide dismutase), and others have structural and regulatory functions such as Alt a 5 and Alt a 12, Alt a 3, Alt a 7. The function of Alt a 1 and Alt a 9 remains unknown. Other four allergens are included in other medical databases (e.g., Allergome): Alt a NTF2, Alt a TCTP, and Alt a 70 kDa. Despite Alt a 1 being the A. alternata major allergen, other allergens, such as enolase, Alt a 6 or MnSOD, Alt a 14 have been suggested to be included in the diagnosis panel of fungal allergy.

Using qPCR and microscopy to assess the impact of harvesting and weather conditions on the relationship between Alternaria alternata and Alternaria spp. spores in rural and urban atmospheres

Alternaria is a plant pathogen and human allergen. Alternaria alternata is one of the most abundant fungal spores in the air. The purpose of this study was to examine whether Alternaria spp. spore concentrations can be used to predict the abundance and spatio-temporal pattern of A. alternata spores in the air. This was investigated by testing the hypothesis that A. alternata dominates airborne Alternaria spp. spores and varies spatio-temporally. Secondarily, we aimed at investigating the relationship between airborne Alternaria spp. spores and the DNA profile of A. alternata spores between two proximate (~ 7 km apart) sites. These were examined by sampling Alternaria spp. spores using Burkard 7-day and cyclone samplers for the period 2016–2018 at Worcester and Lakeside campuses of the University of Worcester, UK. Daily Alternaria spp. spores from the Burkard traps were identified using optical microscopy whilst A. alternata from the cyclone samples was detected and quantified using quantitative polymerase chain reaction (qPCR). The results showed that either A. alternata or other Alternaria species spores dominate the airborne Alternaria spore concentrations, generally depending on weather conditions. Furthermore, although Alternaria spp. spore concentrations were similar for the two proximate sites, A. alternata spore concentrations significantly varied for those sites and it is highly likely that the airborne samples contained large amounts of small fragments of A. alternata. Overall, the study shows that there is a higher abundance of airborne Alternaria allergen than reported by aerobiological networks and the majority is likely to be from spore and hyphal fragments.

Status and Trend of the Main Allergenic Pollen Grains and Alternaria Spores in the City of Rome (2003–2019)

Today a large part of the European population is exposed to levels of air pollution exceeding the standards recommended by the World Health Organization. Moreover, air pollution and the seasonal emission of allergenic pollen are progressively affecting human health and can cause severe allergic reactions, particularly when air pollution combines with pollen allergen peaks. Unlike atmospheric pollutants of anthropogenic origin, pollen sources have a pulsating trend that leads to high values in the flowering period and values close to, or equal to, zero in the rest of the year. This aspect makes essential the definition of data coverage standards for the main allergenic taxa. For air quality assessment detailed classification criteria for monitoring stations are defined by international standards, not the same from the European Standards for the Sampling and analysis of airborne pollen grains and fungal spores. This paper describes the status and the air concentration trends of the main allergenic pollen and the Alternaria spore measured in Rome from 2003 to 2019 by the Aerobiological Monitoring Center of Tor Vergata (Rome) and calculated by the Seasonal Kendall test with the open-source OpenAir R package. The analysis was carried out on the daily concentrations of the most widespread allergenic taxa in Italy: Asteraceae, Betulaceae, Corylaceae, Cupressaceae/Taxaceae, Poaceae, Oleaceae, Urticaceae and the Alternaria spores.

Investigation of spatial and temporal variations of airborne Poaceae, Myrtaceae and Cupressaceae pollen and Alternaria spores in Sydney, Australia, 2017–2020

There is a need for information on pollen exposure to assess allergy risk. Monitoring of aeroallergens in a city is usually limited to the use of a single trap for the whole area. While a single trap provides enough information on background pollen concentration for the area, varying pollen exposure across different urban environments, however, is not considered. In this study, we analysed aerobiological data of three pollen seasons (2017–2020) recorded with a volumetric pollen trap in Sydney, Australia. In order to assess spatial differences in pollen exposure across the city, we installed ten gravimetric traps recording pollen deposition for eight weeks during the summer of 2019/2020. We considered the influence of meteorological variables, land use, urbanisation and distance to the sea. Our results showed differences in pollen season characteristics across the three analysed seasons and correlations with meteorological parameters. Considering all years, we found for Poaceae and Alternaria the strongest positive correlation with mean temperature and for Myrtaceae and Cupressaceae with maximum temperature. Likewise, there were negative correlations with humidity (Myrtaceae, Cupressaceae, Alternaria) and precipitation (Myrtaceae, Cupressaceae). Days with medically relevant pollen and spore concentrations varied between years and we recorded the highest amount in 2017/2018 for Poaceae and Alternaria and in 2019/2020 for Myrtaceae. In addition, we found spatial and temporal variations of pollen deposition. However, we did not detect significant correlations between pollen deposition and land use, which can be attributable to drought conditions prior to the sampling campaign and the temporal setting in the pollen season. This study highlights the importance of continuous volumetric aerobiological monitoring as well as the assessment of pollen exposure at several locations across a large urban area.

Effect of prevailing winds and land use on Alternaria airborne spore load

Alternaria spores are a common component of the bioaerosol. Many Alternaria species are plant pathogens, and their conidia are catalogued as important aeroallergens. Several aerobiological studies showing a strong relationship between concentrations of airborne spore and meteorological parameters have consequently been developed. However, the Alternaria airborne load variation has not been thoroughly investigated because it is difficult to assess their sources, as they are a very common and widely established phytopathogen. The objective of this study is to estimate the impact of vegetation and land uses as potential sources on airborne spore load and to know their influence, particularly, in cases of long-medium distance transport. The daily airborne spore concentration was studied over a 5-year period in León and Valladolid, two localities of Castilla y León (Spain), with differences in their bioclimatic and land use aspects. Moreover, the land use analysis carried out within a 30 km radius of each monitoring station was combined with air mass data in order to search for potential emission sources. The results showed a great spatial variation between the two areas, which are relatively close to each other. The fact that the spore concentrations recorded in Valladolid were higher than those in León was owing to prevailing winds originating from large areas covered by cereal crops, especially during the harvest period. However, the prevailing winds in León came from areas dominated by forest and shrubland, which explains the low airborne spore load, since the main Alternaria sources were the grasslands located next to the trap. Furthermore, the risk days in this location presented an unusual wind direction. This study reveals the importance of land cover and wind speed and direction data for establishing potential airborne routes of spore transport in order to improve the Alternaria forecasting models. The importance of conducting Alternaria aerobiological studies at a local level is also highlighted.

Evaluation of the effect of pre-sowing treatment of grain sorghum seeds with fungicides on the development of blotches in the forest-steppe of the Samara Region

Relevance. It is important to evaluate the effectiveness of modern fungicides and their effect on the development of leaf infections of grain sorghum in order to optimize plant protection against diseases. Methods. The studies were carried out in the fields of the Volga Scientific Research Institute of Selection and Seed-Growing named after P.N. Konstantinov on grain sorghum variety Premiere in 2014–2016. Leaf diseases were estimated by eye in the field during the phases of flowering, milky, waxy, and full grain ripeness. The average lesion of each plant was evaluated, and the prevalence and intensity of disease development was established. Seeds were treated immediately before sowing. Biological effectiveness of the studied fungicides was determined by prevalence and intensity of disease development. Results. Analysis of leaves showed that quite a wide complex of pathogens belonging to the kingdom of fungi caused blotches on sorghum leaves. Mycelium and spores of fungi Alternaria sp., Fusarium sp., Helminthosporium sp. and others were detected on the affected leaves in the stain area. The obtained results allow us to conclude that the development of the fungal leaf blotches in sorghum in the conditions of forest-steppe of the Samara region considerably depends on hydrothermal conditions of the year: the more arid are conditions of May and June, the higher amount of precipitation and thelower temperature is in July, the higher is leaf blotch infestation of sorghum. Seed pretreatment with fungicides suppressed fungal leaf blotch development in the Premiere variety by 13.6–47.0 % in 2014, 6.9–62.2 % – in 2015, and 3.5–53.7 % – in 2016. At the same time, the highest biological efficacy showed treatment of seeds with fungicides of contact-system action “Fundazol” and “Vitaros”; was 25.0–75.0 % in prevalence and 26.2–62.2 % in the intensity of leaf blotch development.

Impact of weather on the behaviour of Alternaria spore and Alt a 1 concentration in the air of Ankara (Turkey)

Intact fungal spores and smaller fungal fragments such as hyphae are sources of airborne allergens. Information on the distribution of sub-spore allergenic particles in the atmosphere is however limited. Therefore, the main aim of this study was to explore the behaviour of Alternaria aeroallergens in the atmosphere of Ankara, central Turkey. Aerobiological monitoring was carried out in the 2020 season. A Burkard volumetric spore trap was used for fungal spore collection, and a high-volume cascade impactor for allergen collection. The Alt a 1 levels in two air fractions (particulate matter (PM) > 10 µm and 10 > PM > 2.5 µm) were measured by an enzyme-linked immunosorbent assay. The seasonal spore integral (SSIn) was 1846 spore day/m3. In the same period, a total of 95.71 pg/m3 Alt a 1 concentration was recorded, of which 93% was recorded in PM>10 and 7% in PM10–2.5 air fraction. The amount of allergen per spore was 5.18 × 10−2 pg/spore/m3. The highest concentration for both spores and allergens was observed on 30 June, i.e. before the local crop harvest. Four days with highest spore levels occurred about one week after the rainfall (> 1 mm). Hot and humid weather probably contributed to the intensive development of fungi and an increase in the concentration of spores in the atmosphere. Our findings suggest that in areas with semi-arid climate, such as central Turkey, the weather conditions have a greater effect on behaviour of the distribution of Alternaria aeroallergens than agricultural practices.

Alternaria spore exposure in Bavaria, Germany, measured using artificial intelligence algorithms in a network of BAA500 automatic pollen monitors

Although Alternaria spores are well-known allergenic fungal spores, automatic bioaerosol recognition systems have not been trained to recognize these particles until now. Here we report the development of a new algorithm able to classify Alternaria spores with BAA500 automatic bioaerosol monitors. The best validation score was obtained when the model was trained on both data from the original dataset and artificially generated images, with a validation unweighted mean Intersection over Union (IoU), also called Jaccard Index, of 0.95. Data augmentation techniques were applied to the training set. While some particles were not recognized (false negatives), false positives were few. The results correlated well with manual counts (mean of four Hirst-type traps), with R2 = 0.78. Counts from BAA500 were 1.92 times lower than with Hirst-type traps.The algorithm was then used to re-analyze the historical automatic pollen monitoring network (ePIN) dataset (2018–2022), which lacked Alternaria spore counts. Re-analysis of past data showed that Alternaria spore exposure in Bavaria was very variable, with the highest counts in the North (Marktheidenfeld, 154 m a.s.l.), and the lowest values close to the mountains in the South (Garmisch-Partenkirchen, 735 m a.s.l.).This approach shows that in our network future algorithms can be run on past datasets. Over time, the use of different algorithms could lead to misinterpretations as stemming from climate change or other phenological causes. Our approach enables consistent, homogeneous treatment of long-term series, thus preventing variability in particle counts owing to changes in the algorithms.

Abundance of aeroallergens in Rujin Sambo Sokoto (north-west), Nigeria

Exposure to aeroallergens has been associated with exacerbation of allergic respiratory diseases especially asthma. It is imperative to identify aeroallergens risk periods and triggers, for adaptation and immunotherapeutic approaches. Study on one-year abundance of aeroallergens was carried out in Rujin Sambo, Sokoto state, Nigeria, from August 2019 to July 2020. Aerosamples were collected using Tauber-like samplers modified to achieve a height of 1.52 m above ground level. Fungal spores were more quantitatively and qualitatively abundant than pollen. Aerosamples were infiltrated with dust in the months of November, March, April and May due to higher incidence of sandstorm, orchestrated by North-East trade wind, which could have refloated previously deposited aeroallergens. Incidence of sandstorm interposed the onset of dry and rainy seasons. The sand storm correlated negatively with humidity but positively with temperature and high influx of fern spores in November. Most fungal spores in the region were spores of Curvularia and Alternaria. Dominant pollen were dispersed from Poaceae, Amaranthaceae/Chenopodiaceae and Pentaclethra macrophylla Benth. In order to over-smart seasonal allergies and elicitation of asthma symptoms in Rujin Sambo, precautionary measures should be taken at the onset of rainy/dry seasons (March, April, May/ November) and August (active-rainy period) and October.

Sentinel-2 satellite and HYSPLIT model suggest that local cereal harvesting substantially contribute to peak Alternaria spore concentrations

Alternaria is a human/animal allergen and plant/animal pathogen. Cereal harvesting emits a large amount of Alternaria spores into the atmosphere. However, estimating the peak spore periods and source areas from large areas is often a challenge because of insufficient observation stations. The purpose of this study was to examine, using remote sensing and an atmospheric transport and dispersion model, the contribution of cereal harvesting to peak Alternaria spore concentrations. Daily Alternaria spores were collected using Hirst-type traps in 12 sites in Europe for the period 2016-2018. Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) back-trajectory and dispersion model was integrated with Sentinel-2 satellite imagery, Corine Land Cover 2018 (CLC2018) and Eurostat cereal data 2016 to map the Alternaria spore peaks and source areas in the 12 sites. Ground truth harvest data, collected at Worcester, UK, in 2018, and meteorological data were used to determine any effect of cereal harvesting and weather on peak spore concentrations. The results showed that the Sentinel-2 satellite detected agricultural areas that underwent intensive harvesting and this coincided with a rapid increase of Alternaria spore concentrations. Furthermore, local agricultural areas cultivated with cereals were the main sources of the peak Alternaria spore concentrations in all the study sites. Remote agricultural and non-agricultural sources, to a lesser extent, contributed to the peak spore concentrations at some sites, e.g. Borstel, Leicester and Worcester. Temperature during the harvesting periods (July and August) was found to significantly contribute to the peak spore concentrations. Overall, the study showed that it is possible to use Sentinel-2 satellite data alongside atmospheric transport and dispersion models to estimate periods of peak Alternaria spore concentrations and sources at a continental scale. This approach can be replicated for other bioaerosols that affect human health, agriculture and forestry.