Abstract
A paralytic shellfish poisoning (PSP) episode developed in summer 2018 in the Rías Baixas (Galicia, NW Spain). The outbreak was associated with an unprecedentedly intense and long-lasting harmful algal bloom (HAB) (~one month) caused by the dinoflagellate Alexandrium minutum. Paralytic shellfish toxins (PSTs) were analyzed in extracts of 45 A. minutum strains isolated from the bloom by high-performance liquid chromatography with post-column oxidation and fluorescence detection (HPLC-PCOX-FLD). PSTs were also evaluated in tissues from marine fauna (invertebrates and fish) collected during the episode and in dolphin samples. The analysis of 45 A. minutum strains revealed a toxic profile including GTX1, GTX2, GTX3 and GTX4 toxins. With regard to the marine fauna samples, the highest PSTs levels were quantified in bivalve mollusks, but the toxins were also found in mullets, mackerels, starfish, squids and ascidians. This study reveals the potential accumulation of PSTs in marine invertebrates other than shellfish that could act as vectors in the trophic chain or pose a risk for human consumption. To our knowledge, this is the first time that PSTs are reported in ascidians and starfish from Spain. Moreover, it is the first time that evidence of PSTs in squids is described in Europe.
Highlights
Paralytic shellfish toxins (PSTs) are a group of natural neurotoxic alkaloids that are the causative agents of paralytic shellfish poisoning (PSP)
It is important to remark that GTX4 shows a relatively high toxicity equivalency factor (TEF), 0.7, according to the European Food Safety Authority EFSA [14]
General characteristics can usually serve to identify the distinction from the toxin composition of other dinoflagellate genera (Pyrodinium and Gymnodinium)
Summary
Paralytic shellfish toxins (PSTs) are a group of natural neurotoxic alkaloids that are the causative agents of paralytic shellfish poisoning (PSP). Fisheries closures and human intoxications due to PSTs have been documented in filter feeders (i.e., bivalve mollusks) and in several non-traditional vectors. These include, but are not limited to, marine gastropods (both carnivorous and grazing), crustaceans (such as lobster and crabs) and fish that acquire the toxins through trophic transfer [7]. Most monitoring programs focus mainly on bivalve mollusks, some countries have regulated PSTs levels in other marine vectors. To our knowledge, studies describing the presence of PSTs on several non-bivalve mollusk marine invertebrate vectors have not been conducted in Spain.
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