Identification of tetrodotoxin in a marine gastropod (Nassarius glans) responsible for human morbidity and mortality in Taiwan

The toxicity of the gastropod Nassarius glans was investigated. This gastropod was implicated in an incident of food paralytic poisoning on Tungsa Island, Taiwan, in April 2004. Six victims consumed both digestive glands and muscle. These tissues contained high concentrations of toxin; their highest toxicity scores were 2,048 and 2,992 MU/g, respectively, based on the tetrodotoxin (TTX) bioassay. The toxin was purified from these gastropods and analyzed by high-performance liquid chromatography, which revealed TTX and related compounds 4-epi TTX and anhydro-TTX; paralytic shellfish poisons were not found. The urine and blood samples from patients were cleansed using a C18 Sep-Pak cartridge column and 3,000 molecular weight cutoff Ultrafree microcentrifuge filters, and the eluate was filtered and analyzed by liquid chromatography and mass spectrometry. The detection limit for TTX was 1 ng/ml. The standard curves were linear in the range 30 to 600 ng/ml for urine and 1 to 30 ng/ml for blood. TTX was detected in all urine samples but in only three of four blood samples tested. Thus, the causative agent of gastropod food poisoning was identified as TTX.