The effect of local cropping activities and weather on the airborne concentration of allergenic Alternaria spores in rural Australia

Abstract

Atopy to the fungus Alternaria is strongly associated with respiratory disease. The prevalences of asthma and of allergy to Alternaria are high amongst children living in rural towns of southeastern Australia. In such towns, airborne allergenic spores have been proposed to arise from nearby crops, but this has not been tested and crops are unlikely to be the only sources of Alternaria. We sought to identify sources and factors that in¯uence concentrations of spores of Alternaria detected in rural towns. Over two years, we sampled spores in two towns (Wagga Wagga and Moree, New South Wales, Australia), in nearby wheat and cotton crops during harvesting and control periods, in a cotton gin and a grain shed. Alternaria was present in both towns throughout the study, and above the crops, at the gin and grain shed. Daily and annual concentrations were amongst the highest recorded worldwide and peaks persisted for six months in Wagga Wagga and ten months in Moree. Crop maturation aVected the spore load in the air more than the actual days of harvest. Regression analysis showed that the overall spore concentrations above towns correlated with those above crops. Variables of rainfall and maximum temperature correlated with concentrations in both towns, and additionally wind direction in Wagga Wagga. In conclusion, crops and produce handling released spores into the air that reached nearby rural towns, with peaks in spore concentrations following warm temperatures and recent rainfall.

Airborne allergenic fungal spores and meteorological factors in Greece: Forecasting possibilities

“…Thus, it refers not only to the direct 'dose-response effect', but also to the construction of time-delayed relations (lags) among various variables (Chatfield, 1989). It is well known that environmental data collected over consecutive time periods are often serially correlated, with data closely associated having higher correlations between them than data farther apart (Katial et al 1997;Mitakakis et al 2001;Munuera Giner et al 2001;Stennett & Beggs, 2004). Similarly to dependent and independent variables, regression errors could additionally be correlated serially.…”

“…These variables were: mean, maximum and minimum air temperature (in˚C), relative humidity (%), solar radiation (mWh/cm 2 ), atmospheric pressure (mm Hg), and presence or absence of dew (0, 1). All the above meteorological parameters are considered as the most important for fungal spore shedding, dispersion, and transport (Solomon, 1978;Hjelmroos, 1993;Katial et al 1997;Kurkela et al 1997;Angulo-Romero et al 1999;Corden & Millington, 2001;Mitakakis et al 2001;Munuera Giner et al 2001;Troutt & Levetin, 2001;Stennett & Beggs, 2004). Taking into consideration the special contribution of the parameters of rain and wind to spore circulation (Solomon, 1978;Hjelmroos, 1993;Katial et al 1997;Kurkela, 1997;Mitakakis et al 2001;Troutt & Levetin, 2001), we additionally inserted variables referring to their interaction effect.…”

“…The dispersal and transport of airborne fungal spores -and therefore the predictive power of created statistical models -are influenced by several meteorological factors, such as wind, rainfall and air temperature components, atmospheric pressure, solar radiation, and relative humidity (Solomon, 1978;Hjelmroos, 1993;Katial et al 1997; Kurkela, 1997;Angulo-Romero et al 1999;Corden & Millington, 2001;Mitakakis et al 2001;Munuera Giner et al 2001;Troutt & Levetin, 2001;Stennett & Beggs, 2004). Nevertheless, the exact relationship of spore counts and meteorological factors is not thoroughly understood.…”

“…However, the majority of these efforts have more frequently aimed at the prediction of airborne pollen count; advanced forecasting models of airborne fungal spore circulation are comparatively few (Katial et al 1997), and most of them usually display low predictability (AnguloRomero et al 1999;Mitakakis et al 2001;Troutt & Levetin, 2001;Stennett & Beggs, 2004).…”

Microbiology and atmospheric processes: research challenges concerning the impact of airborne micro-organisms on the atmosphere and climate

“…High concentrations of air-borne bacteria and fungal spores frequently occur from spring to fall in temperate areas of the world, mainly due to the fact that leaf surfaces are a major source of fungi (Levetin and Dorsey, 2006;Mitakakis et al, 2001) and bacteria (Tong and Lighthart, 2000) in the air. The higher concentrations of bacteria observed in the summer (JulyAugust) over two agricultural sites in Oregon (USA) may reflect the flux from agricultural sources and activities and dry dusty soil conditions at this time of the year (Tong and Lighthart, 2000).…”