First Finding of Ostreopsis cf. ovata Toxins in Marine Aerosols

Since the late 1990’s, a respiratory syndrome has been repetitively observed in humans concomitant with Ostreopsis spp. blooms (mainly O. cf. ovata) in the Mediterranean area. Previous studies have demonstrated that O. cf. ovata produces analogues of palytoxin (ovatoxins and a putative palytoxin), one of the most potent marine toxins. Based on the observed association between O. cf. ovata blooms, respiratory illness in people, and detection of palytoxin complex in algal samples, toxic aerosols - containing Ostreopsis cells and/or the toxins they produce - were postulated to be the cause of human illness. However the presence of toxins in the aerosols has never been proved. A small scale monitoring study of marine aerosols carried out along the Tuscan coasts (Italy) in 2009 and 2010 is reported. Aerosols were collected concurrently O. cf. ovata blooms and they were analyzed by both PCR assays and LC-HRMS technique. The results, besides confirming the presence of O. cf. ovata cells, demonstrated for the first time the occurrence of ovatoxins in the aerosol at levels of 2.4 pg of ovatoxins per air liter. Given the lack of toxicological data on palytoxins by inhalation exposure, our results move the first unavoidable step towards a more comprehensive understanding of the Ostreopsis-related respiratory syndrome.