Dinophysis Toxins: Causative Organisms, Distribution and Fate in Shellfish

Abstract

Several Dinophysis species produce diarrhoetic toxins (okadaic acid and dinophysistoxins) and pectenotoxins, and cause gastointestinal illness, Diarrhetic Shellfish Poisoning (DSP), even at low cell densities (<103 cells·L−1). They are the main threat, in terms of days of harvesting bans, to aquaculture in Northern Japan, Chile, and Europe. Toxicity and toxin profiles are very variable, more between strains than species. The distribution of DSP events mirrors that of shellfish production areas that have implemented toxin regulations, otherwise misinterpreted as bacterial or viral contamination. Field observations and laboratory experiments have shown that most of the toxins produced by Dinophysis are released into the medium, raising questions about the ecological role of extracelular toxins and their potential uptake by shellfish. Shellfish contamination results from a complex balance between food selection, adsorption, species-specific enzymatic transformations, and allometric processes. Highest risk areas are those combining Dinophysis strains with high cell content of okadaates, aquaculture with predominance of mytilids (good accumulators of toxins), and consumers who frequently include mussels in their diet. Regions including pectenotoxins in their regulated phycotoxins will suffer from much longer harvesting bans and from disloyal competition with production areas where these toxins have been deregulated.

Co-occurrence of Dinophysis tripos and pectenotoxins in Argentinean shelf waters

“…The dinoflagellate genus Dinophysis is considered as the only source of PTX in marine waters (Reguera et al, 2014). Several PTX analogs have been found in culture conditions, field water samples and shellfish (Domínguez et al, 2010).…”

“…A few hundred cells per liter are enough to generate intoxications in humans by consuming contaminated shellfish (Yasumoto et al, 1980). Up to date, dinoflagellate species of the genus Dinophysis have been recently recognized as the only known source of pectenotoxins (PTX), a large family of lipophilic toxins originally associated with the DSP toxin complex (Reguera et al, 2014). Toxicological studies indicate that PTX are not diarrheagenic after oral administration to laboratory rodents, but PTX-1 is highly hepatotoxic and the other analogs are assumed to have similar effects (Terao et al, 1986).…”

“…Of these, 10 toxic species are known as the main source of okadaic acid and its analogs, causative of diarrheic shellfish poisoning (DSP) in humans (Reguera et al, 2014). A few hundred cells per liter are enough to generate intoxications in humans by consuming contaminated shellfish (Yasumoto et al, 1980).…”

Dinophysis Species Associated with Diarrhetic Shellfish Poisoning Episodes in North Patagonian Gulfs (Chubut, Argentina)

“…In the Argentine Sea, it is known to occur between 36°and 55°S (Balech 2002). But D. tripos has never been cited as the causative agent of DSP events when it was the only or the overwhelmingly dominant species of Dinophysis in the microphytoplankton (Reguera et al 2014). In contrast, Dinophysis acuminata has been identified as the causative agent of DSP in Southern Brazil (Proenc xa et al 2007) and, combined with Dinophysis caudata, in Uruguay (M endez & Ferrari 2002) and Argentina (Sar et al 2010).…”

Primary productivity and phytoplankton dynamics in a subtropical estuary: a multiple timescale approach

“…Dinophysis spp. produce lipophilic toxin that, upon accumulation in bivalve mollusks, can cause diarrhetic shellfish poisoning in human consumers (Reguera et al 2014), and they have been recently reported in various shellfish farms of the Santa Catarina coast (Proença et al 2007(Proença et al , 2011.…”