Temporal association of Ostreopsis cf. ovata blooms and human health disorders: results of simultaneous epidemiology and ecological studies

Abstract

During the last 15 years, recurrent blooms of the toxic benthic dinoflagellate Ostreopsis are occurring in the Mediterranean coasts and other temperate waters. Recent observations suggest the potential expansion of this tropical organism as a result of climate warming. In several Mediterranean beaches, human health affectations through inhalation of suspected toxic aerosols or cutaneous irritation through skin contact have been documented coinciding with massive blooms of Ostreopsis. Paradoxically, while the Ostreopsis proliferations usually persist for more than two months, health symptoms lasted only for a short time. Here we will show the results of the joint epidemiology and ecology studies addressed to clarify this discrepancy. The research was performed in 2013 and 2014 along the Ostreopsis bloom period in the Llavaneres beach hot spot (NW Mediterranean). In both years, the health disorders peaked coinciding with the transition from the exponential to the stationary growth phase of the Ostreopsis bloom. Based on the overall ecological and meteorological data, we hypothesize that the irritative agents would be released to the environment coinciding with that particular physiological state of the Ostreopsis cells