Tetrodotoxin poisoning following ingestion of the toxic eggs of the horseshoe crab Carcinoscorpius rotundicauda, a case series from 1994 through 2006.

Between 1994 and 2006, a total of 280 cases of varying degrees of tetrodotoxin poisoning following ingestion of the toxic eggs of the horseshoe crab, Carcinoscorpius rotundicauda, were admitted to the medical service of Chon Buri Hospital. The severity of the poisoning was classified into four stages based on clinical signs and symptoms of human tetrodotoxication. Of 245 available medical records; 100 were in stage 1, 74 were in stage 2, 3 were in stage 3 and 68 were in stage 4. The frequencies of symptoms and signs included the following : circumoral and lingual numbness (98%), hands and feet numbness (94.7%), weakness (59.6%), dizziness and vertigo (54.3%), nausea and vomiting (52.6%), transient hypertension (39.6%), respiratory paralysis (27.7%), fixed dilated pupils (14.7%), ophthalmoplegia (12.2%), blood pressure lower than 90/60 mmHg (5.7%), and polyuria (0.4%). All patients received symptomatic and supportive treatment. Endotracheal intubation and mechanical ventilation were considered when paralysis was progressing rapidly. The results of treatment are as follows: 239 patients (97.5%) showed complete recovery, 5 patients (2%) died, and 1 patient (0.4%) suffered anoxic brain damage. Horseshoe crab poisoning occurs both sporadically and epidemically in Chon Buri. Seasonal variation in the number of cases of poisoning was observed with a peak from December through March.

An outbreak of horseshoe crab poisoning in Chon Buri, Thailand: clinical, toxicologic and therapeutic considerations.

In 1994-1996, an outbreak of horseshoe crab poisoning by eating toxic eggs of the horseshoe crab Carcinoscorpius rotundicauda affected over 100 persons in Chon Buri which located on the eastern coast of Thailand. We discuss clinical description and management of this first major outbreak. The responsible toxin has been partially purified by means of ultrafiltration and high performance liquid chromatography. The horseshoe crab toxin is identified as tetrodotoxin (TTX) and anhydro TTX.

An epidemic of tetrodotoxin poisoning following ingestion of the horseshoe crab Carcinoscorpius rotundicauda.

At certain seasons of the year in Thailand, the horseshoe crab Carcinoscorpius rotundicauda may be toxic to human and fatal poisoning occasionally occur. Tetrodotoxin (TTX) and its derivatives were major toxins in the toxic eggs of the horseshoe crab. An epidemic of poisoning by eating toxic eggs of the horseshoe crab affected 71 persons in Chon Buri which located in the eastern coast of Thailand. Patients generally presented with neurologic symptoms such as paresthesia, vertigo, weakness, respiratory paralysis, altered consciousness with unreactive dilated pupils in addition to gastrointestinal symptoms such as nausea and vomiting. Nineteen patients required artificial ventilation and there were two deaths. This is the first large outbreak of tetrodotoxin poisoning recognized in Thailand.