Non-Traditional Vectors for Paralytic Shellfish Poisoning

Abstract

Paralytic shellfish poisoning (PSP), due to saxitoxin and related compounds, typically results from the consumption of filter-feeding molluscan shellfish that concentrate toxins from marine dinoflagellates. In addition to these microalgal sources, saxitoxin and related compounds, referred to in this review as STXs, are also produced in freshwater cyanobacteria and have been associated with calcareous red macroalgae. STXs are transferred and bioaccumulate throughout aquatic food webs, and can be vectored to terrestrial biota, including humans. Fisheries closures and human intoxications due to STXs have been documented in several non-traditional (i.e. non-filter-feeding) vectors. These include, but are not limited to, marine gastropods, both carnivorous and grazing, crustacea, and fish that acquire STXs through toxin transfer. Often due to spatial, temporal, or a species disconnection from the primary source of STXs (bloom forming dinoflagellates), monitoring and management of such non-traditional PSP vectors has been challenging. A brief literature review is provided for filter feeding (traditional) and nonfilter feeding (non-traditional) vectors of STXs with specific reference to human effects. We include several case studies pertaining to management actions to prevent PSP, as well as food poisoning incidents from STX(s) accumulation in non-traditional PSP vectors.

Toxic Alexandrium peruvianum (Balech and de Mendiola) Balech and Tangen in Narragansett Bay, Rhode Island (USA)

“…This saxitoxin profile is distinct within the A. peruvianum/A. ostenfeldii clade in that it lacks B2, which is present in A. ostenfeldii (Hansen et al, 1992;MacKenzie et al, 1996;Cembella et al, 2000;Deeds et al, 2008;Tomas et al, 2012). The A. peruvianum saxitoxin profile is distinct in that there was no evidence of N-1-hydroxy saxitoxins, or evidence of Neo, B2, GTX1, GTX4 and C3 or C4.…”

Improved phylogenetic resolution of toxic and non-toxic Alexandrium strains using a concatenated rDNA approach

“…A reported 57 STX analogues are known to date (Anderson et al, 2002;Kellmann et al, 2010;Sellner et al, 2003;Wiese et al, 2010), with the genes required for saxitoxin-synthesis in Alexandrium recently being identified (Stü ken et al, 2011). These toxins can cause severe symptoms upon consumption of vector species, including filter feeding invertebrates such as shellfish, crustaceans, mollusks, gastropods and planktivorous fish (Deeds et al, 2008). PSTs work by reversibly binding voltage-gated Na+ channels, blocking the neural pore, resulting in the occasionally fatal paralytic shellfish poisoning (PSP) (Catterall, 1980;Catterall et al, 1979;Cestele and Catterall, 2000).…”

Distribution and selective elimination of paralytic shellfish toxins in different tissues of Octopus vulgaris

“…Besides bivalve molluscs, non filter-feeding organisms such as crustaceans, fishes and cephalopods are also exposed to marine toxins trough complex trophic interrelationships (Landsberg, 2002;Deeds et al, 2008). Accumulation and transfer of marine toxins frequently occur without outward signs of toxicity (Doucette et al, 2006;Costa et al, 2008;Deeds et al, 2008;Jester et al, 2009). Nevertheless, sporadic toxic episodes with large-scale mortalities of marine animals, causing devastating impacts in the ecosystem, have been reported worldwide (Landsberg, 2002).…”