Establishing the link between <em>Ostreopsis</em> cf.<em>ovata</em> blooms and human health impacts using ecology and epidemiology

Abstract

Summary:Blooms of the benthic dinoflagellate Ostreopsis have been related to sporadic acute respiratory symptoms and general malaise in people exposed to marine aerosols on some Mediterranean beaches. However, the direct link between recurrent Ostreopsis blooms and health problems has not been clearly established. In order to establish and elucidate the connection, we conducted a joint ecology and epidemiology study in an Ostreopsis hot spot. Throughout the bloom, which extended from the end of June until the end of October 2013, 81% of the human cohort that we studied experienced at least one Ostreopsis-related symptom. Paradoxically, the time when the effects were greatest was during a short time window in early August. This corresponded to the transition from the exponential growth to the stationary phase of the bloom. Negligible symptoms were reported from August to mid-October, during the stationary period of the proliferation, when O. cf. ovata maintained high concentrations of epiphytic cells. No clear patterns in the landward wind component were noted during the time when health effects were greatest. Our main hypothesis is that the irritants present in the aerosol are produced during a particular physiological phase of the Ostreopsis cells during the bloom.Keywords: Ostreopsis, epidemiology, Mediterranean, HAB, dinoflagellates, respiratory irritation.Aproximación ecológica y epidemiológica para establecer la relación entre las proliferaciones de Ostreopsis cf. ovata y sus impactos sobre la salud humana Resumen: Las proliferaciones del dinoflagelado bentónico Ostreopsis en algunas playas del Mediterráneo se han relacionado con síntomas respiratorios agudos esporádicos y malestar general en las personas expuestas a los aerosoles marinos. Sin embargo, la relación directa entre las proliferaciones recurrentes de Ostreopsis y los problemas en la salud no ha sido claramente establecida. Con el fin de establecer esta conexión se realizó un estudio ecológico y epidemiológico conjunto en una playa afectada por dichos eventos. A lo largo de la proliferación, que se extendió desde finales de junio hasta finales de octubre de 2013, el 81% de la cohorte humana estudiada presentó al menos un síntoma relacionado con los potencialmente producidos por Ostreopsis. Paradójicamente, la mayoría de los efectos se produjeron durante un breve período de tiempo, a principios de agosto, coincidiendo con la transición de la fase de crecimiento exponencial de la proliferación a la fase estacionaria. A partir de agosto y hasta mediados de octubre, durante dicha fase estacionaria en que se mantuvieron concentraciones elevadas de O. cf. ovata, los síntomas fueron negligibles. Durante el período de tiempo con mayor afectación en la salud, no se observó un patrón claro en la componente de viento de mar hacia tierra. Nuestra hipótesis principal es que los compuestos irritantes presentes en el aerosol se producen durante una fase fisiológica particular de las células de Ostreopsis en un momento concreto de la proliferación.Palabras clave...

Variability of planktonic and epiphytic vibrios in a coastal environment affected by <em>Ostreopsis</em> blooms

“…siamensis (Penna et al 2005, Battocchi et al 2010, Vila et al 2012b). These blooms have often been related to respiratory symptoms in beach users or persons taking a nearshore walk in Mediterranean countries since the late 1990s (see Vila et al 2016) and are thought to have been the cause of a massive mortality of benthic invertebrates in Llavaneres in August 1998 (Vila et al 2008). The mortality of benthic invertebrates and fishes (Simoni et al 2004, Shears andRoss 2009) has been documented at other locations, as have other noxious effects, such as human foodborne intoxications (Tubaro et al 2011).…”

Marine Dinoflagellate Assemblage in the Galápagos Marine Reserve

“…For example, Gambierdiscus spp., can cause ciguatera fish poisoning, a disease with worldwide impact, though mainly in tropical zones (Parsons et al, 2012), and Ostreopsis cf. ovata blooms that have been seen to affect human health directly by inhalation of marine aerosols that cause respiratory irritation (Vila et al, 2016).…”

Harmful Algal Blooms in Benthic Systems: Recent Progress and Future Research

“…A recent simultaneous epidemiology and ecology study in an O. cf. ovata hotspot suggested that the health symptoms seem to occur during short periods within a longer bloom event (Vila et al, 2016). The irritating compounds could be produced during a particular physiology cell stage, and certain wind and water hydrodynamic conditions could facilitate dispersion; however, more in-depth studies are required to prove these connections.…”

“…In the Mediterranean, blooms O. cf. ovata near certain beaches have been related to acute respiratory irritation (rhinorrhoea, pharyngeal pain, dry cough, nose irritation) and general malaise, headache, fever (≥38ºC), eye irritation, and/or dermatitis (references in Vila et al, 2016). Most of the symptoms disappear within a few hours without specific medication when people move away from the area affected by the Ostreopsis bloom, and people exposed to the irritative aerosol rarely require hospitalization.…”

“…Temperature windows (23°C to 27.5°C) allow Ostreopsis growth along the French Mediterranean coast where the first epiphytic cells were detected at 13.0°C, and high abundances (>10,000 cells g -1 of macroalgae wet weight) began to occur at 18°C (Cohu et al, 2013). Southward, along Spain's Catalan coast, bloom burst usually starts at the end of June (Vila et al, 2016), after a sustained increase in air and water temperatures above a threshold of 20°C and wind intensities below 3 m s -1 (on average). Along the Atlantic coast of the Iberian Peninsula, absolute temperature alone cannot explain Ostreopsis distribution (David et al, 2012); three continuous months with sea surface temperature above 19.5°C may be necessary for Ostreopsis to be present in that area.…”