HABs causing aerosol and/or direct contact toxicity: gained knowledge and open questions

The 18th International Conference on Harmful Algae (ICHA), From ecosystems to socio-ecosystems, 21-26 October 2018, Nantes, France.-- 1 page
Human respiratory irritation associated with HABs was first documented by Taylor (1917) during his observations of Karenia brevis (formerly Gymnodinium breve) blooms in the west coast of Florida, also causing massive fish mortalities. Later, Woodcock (1948) provided the first evidences of the link between respiratory symptoms and aerosolized compounds produced by the dinoflagellate. In the last 30 years, concerted well-funded interdisciplinary and multi-agency research has been intensively conducted to understand K. brevis blooms (also know as Florida red tides) dynamics, and the exposure and health effects of aerosolized toxins (brevetoxins). Advances include early warning systems monitoring the presence of Karenia brevis and its bloom dynamics (combining in situ sampling, autonomous vehicles, remote sensing), a detailed knowledge on the involved toxins (mainly brevetoxins PbTx-2 and PbTx-3 in both water and aerosols) and their mode of action, the relevance of meteorology factors in the transport of aerosolized toxins, and a better understanding of the human exposures and health effects. At the same time, substantial work has gone into prevention of this exposure and health effects including community and expert education, beach warnings and involving Poison Control Centers. In the last 20 years, a new environmental and human health threat seems to be emerging in temperate latitudes, and specially in Mediterranean coasts. Blooms of the marine benthic dinoflagellate genus Ostreopsis are linked to cutaneous and/or respiratory problems on beach goers and people that work or inhabit in areas where this species thrives, and were in contact with benthic or planktonic toxic cells and/or exposed for certain hours to aerosols. Although the impacts are mild by now, alarm has been raised because this species produces palytoxins (PLTX) and analogues, being PLTX potent biotoxins associated to fatal seafood borne intoxications in the tropics. Whether those toxins are at the origin of cutaneous and respiratory health problems is still unknown. Before Ostreopsis could constitute a bigger problem, multidisciplinary investigation has been and it is conducted nowadays by different research teams and a communication network has been implemented with environmental and public health authorities in the affected countries. In this presentation we will compare the available information about the harmful benthic (Ostreopsis spp.) and planktonic (Karenia brevis) blooms, with the aim of identifying gaps in knowledge and further steps to progress and design appropriate human health prevention plans. Analogous comparison will also be done concerning freshwater toxic cyanobacteria blooms causing cutaneous and respiratory irritative symptoms