Dynamics of airborne Leptosphaeria and Alternaria spores in Havana, Cuba

This study analyzes the atmospheric dynamics of Leptosphaeria and Alternaria spores in Havana, Cuba, using a non-viable volumetric sampler. The spores were quantified, and their aerobiological behaviour was plotted against meteorological variables over an eight-year period. A total of 173,155 spore * day/m³Leptosphaeria and 3686 spore * day/m³Alternaria were recorded. Both reached their peak concentrations during the rainy season (May-October), with interannual fluctuations. The Main Spore Season extended over multiple months each year, with greater presence between April and August, and more variability at the beginning and end of each annual cycle. Leptosphaeria spores predominated in the air during the early morning hours, while Alternaria spores showed peaks in the air during the daytime. Statistical analysis revealed a positive association between Leptosphaeria and relative humidity, as well as with rainfall accumulated up to three days before. On the other hand, Alternaria was positively correlated with temperature and negatively with minimum relative humidity. A logistic regression model was obtained to predict the probability of finding concentrations of Leptosphaeria spores in the air above 63 spores/m³, taking into account temperature, relative humidity and rainfall. However, in the case of Alternaria, the model obtained had limited discriminative power. These findings highlight the influence of climate on the presence of allergenic spores and underscore the key role of the interaction between temperature and relative humidity in their atmospheric dynamics. The study contributes to a better understanding of aerobiological impact in tropical climates and suggests potential applications in the field of public health.