Paralytic shellfish poisoning toxins in green mussels (Perna viridis) from the Gulf of Paria, Trinidad

Paralytic shellfish poisoning (PSP) toxins were determined in green mussels (Perna viridis) collected from one collection site in the Gulf of Paria in Trinidad in 1999 and 2000. Aqueous extracts of PSP were purified by passage through C-18 SPE cartridges, oxidized with peroxide and periodate, respectively, then analyzed by HPLC with fluorescence detection. This procedure provided rapid and highly sensitive screening of samples for PSP toxins. Further purification of PSP-containing extracts using COOH SPE cartridges resulted in the separation and identification of individual PSP toxins. The method of analysis was validated by spike and recovery experiments, with 85-103% recoveries of mixed toxins. PSP toxins determined in our samples in both years were GTX2,3, dcGTX2,3, STX, and dcSTX, while GTX1,4 and NeoSTX were only identified in 1999 and 2000, respectively. In 1999, GTX1,4, GTX2,3 and dcGTX2,3 predominated, as compared to NeoSTX, GTX2,3 and dcGTX2,3 in 2000. However, mussel samples in 2000 contained higher total concentrations of detected PSP toxins than those of 1999. These results represent the first identification of specific PSP toxins in local shellfish and provide a basis for effective monitoring and control of these toxins in Trinidad.

Evidence for PSP in mussels in Trinidad

Herein we present the first evidence for the presence of Paralytic Shellfish Poison (PSP) in Trinidadian waters. The toxin was found in a meat extract of the mussel, Perna viridis. PSP has not previously been demonstrated in the shellfish of Caribbean islands. The presence of PSP in Trinidad is therefore significant in that it presents an opportunity to better understand the dynamics of PSP and algal blooms in both a region and island environment not normally associated with PSP.P. viridis is not native to Trinidad, but rather originates from eastern Asia. It presented itself only recently in Trinidadian waters. Interestingly, shellfish consumption and algal blooms have had a long history of coexistence in Trinidad without any record of human intoxications. In this context, potential Public Health implications of finding PSP in a non-native shellfish species are briefly discussed.