The first report on the marine snail Phos senticosus (Linnaeus, 1758) causing a tetrodotoxin poisoning in Viet Nam

The neurotoxic poisonings that result in death with fatalities caused by consumption of Nassarius snails have been reported in Viet Nam but the causative toxin has only been identified in a small number of cases. A poisoning incident by eating marine snails happened in Binh Thuan Province, Viet Nam in March 2021. The leftover food from the incident, 29 snail specimens, later were identified as all Phos senticosus (Linnaeus, 1758) were collected for identification of causative toxin. At 60.7 ± 126.5 µg/g, anh-TTX was detected in the most dominant level, followed by tetrodotoxin (TTX) (46.0 ± 107.6 µg/g) and 4-epiTTX (23.3 ± 24.3 µg/g) by hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) analysis. Overall toxicity was assessed to be 229 ± 526 MU/g in the snail specimens that responded mostly to TTX due to its strong potency. All specimens were reported as toxic in toxicity range of 10–2,672 MU/g, which is comparable to what was found in some other Nassarius species in Taiwan and Viet Nam. Of 29 specimens, 75.8% showed toxicity in the range of 10–100 MU/g, 17.3% indicated toxicity in the range of 100––1,000 MU/g, whereas 6.9% displayed toxicity that was exceptionally high (> 1,000 MU/g). The data demonstrates that TTX is accountable for this poisoning incident. Notebly, it is the first report on TTX in P. senticosus causing the seafood poisoning in Viet Nam, highlighting the threat this species poses to human consumption. As a result, there ought to be a more severe warning about its potential cause of poisoning.