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Original Article


Outdoor Allergenic Fungal Spores: Comparison Between an Urban and a Rural Area in Northern Portugal


M Oliveira,1,2 H Ribeiro,1,2 L Delgado,3,4 J Fonseca,4 MG Castel-Branco,3 I Abreu1,2

1Environment, Society and Education Group, Geology Centre, University of Porto, Porto, Portugal
2Botanical Department, Faculty of Sciences, University of Porto, Porto, Portugal
3Allergology Department, São João Hospital, Porto, Portugal
4Immunology Department, Faculty of Medicine, University of Porto, Porto, Portugal

J Investig Allergol Clin Immunol 2010; Vol. 20(2): 117-128



Background: The frequency and concentration of many airborne fungal spores associated with respiratory allergy symptoms are influenced by geographical and climatic characteristics.

Objective: The aim of this work was to monitor the distribution of 11 potentially allergenic fungal spore types in 2 regions with different
urbanization levels in Northern Portugal: Porto (urban area) and Amares (rural area).

Methods: Airborne fungal spore levels were monitored from 2005 to 2007 using Hirst-type spore traps. The Spearman correlation test was used to analyze the influence of meteorological factors (temperature, relative humidity, and rainfall) on spore concentration. Meteorological data from both areas were compared using the t test, and spore concentrations were compared using the sign test.

Results: In both areas, Cladosporium, Agaricus, Aspergillus/Penincillium, Alternaria, Coprinus, and rusts were the most abundant fungal types observed. Most of the analyzed spore types presented maximum values during the summer months, with the exception of Polythrincium, Stemphylium, and Torula, which reached a peak earlier in the year, whereas Aspergillus/Penicillium and Botrytis showed a wider distribution. Temperature had a positive effect on most spore concentrations, and relative humidity and rainfall negatively infl uenced concentrations of Alternaria, Cladosporium, Epicoccum, and Torula.

Conclusions: The concentration of all selected spore types was higher in the rural than in the urban area, with higher values registered during summer and autumn and lower values found during winter and spring. Meteorological parameters, such as air temperature, humidity and rainfall, influence airborne concentrations of major allergenic fungal spores.

Key words: Aerobiology. Allergens. Fungal spores. Rural area. Urban area.