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Tetrodotoxin Poisoning Associated With Eating Puffer Fish Transported from Japan -- California, 1996

On April 29, 1996, three cases of tetrodotoxin poisoning occurred among chefs in California who shared contaminated fugu (puffer fish) brought from Japan by a co-worker as a prepackaged, ready-to-eat product. The quantity eaten by each person was minimal, ranging from approximately 1/4 to 1 1/2 oz. Onset of symptoms began approximately 3-20 minutes after ingestion, and all three persons were transported by ambulance to a local emergency department (ED). This report summarizes the investigation of these cases by the San Diego Department of Environmental Health (SDEH) and the Food and Drug Administration (FDA). Case Reports

Case 1. A 23-year-old man ate a piece of fugu "the size of a quarter" (approximately 1/4 oz). Approximately 10-15 minutes later, he had onset of tingling in his mouth and lips followed by dizziness, fatigue, headache, a constricting feeling in his throat, difficulty speaking, tightness in his upper chest, facial flushing, shaking, nausea, and vomiting. His legs weakened, and he collapsed. On examination in the ED, his blood pressure was 150/90 mmHg; heart rate, 117 beats per minute; respiratory rate, 22 per minute; temperature, 99.3 F (37.4 C); and oxygen saturation, 99% on room air.

Case 2. A 32-year-old man ate three bites of fugu (approximately 1 1/2 oz) over 2-3 minutes. While eating his third bite, he noticed tingling in his tongue and right side of his mouth followed by a "light feeling," anxiety, and "thoughts of dying." He felt weak and collapsed. At the ED, his blood pressure was 167/125 mmHg; heart rate, 112 beats per minute; respiratory rate, 20 per minute; and oxygen saturation, 96% on room air.

Case 3. A 39-year-old man ate approximately 1/4 oz of fugu after eating a full meal. Approximately 20 minutes after eating the fugu, he had onset of dizziness and mild chest tightness. At the ED, his blood pressure was 129/75 mmHg; heart rate, 84 beats per minute; respiratory rate, 22 per minute; temperature, 97.2 F (36.2 C); and oxygen saturation, 97% on room air. Diagnosis and Treatment

A presumptive diagnosis of tetrodotoxin poisoning in all three men was based on clinical presentation in the ED and the history of recent consumption of fugu. All were treated with intravenous hydration, gastric lavage, and activated charcoal. Symptoms gradually resolved, and the men were discharged the following day with no residual symptoms. Follow-Up Investigation

The chef who brought the fugu from Japan failed to declare this item through customs. The remaining fugu was obtained for toxin analysis at FDA. SDEH contacted health authorities in Japan and relayed the product label information for identification of the product manufacturer to assist in their local follow-up investigation.

Reported by: P Tanner, San Diego Dept of Environmental Health; G Przekwas, R Clark, MD, San Diego Regional Poison Center, Univ of California at San Diego Medical Center; M Ginsberg, MD, San Diego County Health Dept; S Waterman, MD, State Epidemiologist, California Dept of Health Svcs. Food and Drug Administration. Div of Environmental Hazards and Health Effects, National Center for Environmental Health; Div of Field Epidemiology, Epidemiology Program Office, CDC.

Editorial Note

Editorial Note: The order Tetraodontoidea includes ocean sunfishes, porcupine fishes, and fugu, which are among the most poisonous of all marine life (1). These species inhabit the shallow waters of the temperate and tropical zones and can be exported from China, Japan, Mexico, the Philippines, and Taiwan. The liver, gonads, intestines, and skin of these fish contain tetrodotoxin, a powerful neurotoxin that can cause death in approximately 60% of persons who ingest it (2). Other animals (e.g., California newt and the eastern salamander) also possess tetrodotoxin in lethal quantities (3) (Table_1).

Tetrodotoxin is heat-stable and blocks sodium conductance and neuronal transmission in skeletal muscles. Paresthesias begin 10-45 minutes after ingestion, usually as tingling of the tongue and inner surface of the mouth. Other common symptoms include vomiting, lightheadedness, dizziness, feelings of doom, and weakness. An ascending paralysis develops, and death can occur within 6-24 hours, secondary to respiratory muscle paralysis. Other manifestations include salivation, muscle twitching, diaphoresis, pleuritic chest pain, dysphagia, aphonia, and convulsions. Severe poisoning is indicated by hypotension, bradycardia, depressed corneal reflexes, and fixed dilated pupils. Diagnosis is based on clinical symptoms and a history of ingestion. Treatment is supportive, and there is no specific antitoxin (6). Despite the high death rate associated with tetrodotoxin poisoning, the three persons described in this report survived probably because of the small amount of toxin ingested and rapid stomach evacuation by the ED.

Although personal importation of fugu into the United States is prohibited, FDA has permitted fugu to be imported and served in Japanese restaurants by certified fugu chefs on special occasions. A cooperative agreement with the Japanese Ministry of Health and Welfare ensures fugu is properly processed and certified safe for consumption before export by the government of Japan. If cleaned and dressed properly, the fugu flesh or musculature is edible and considered a delicacy by some persons in Japan, who may pay the equivalent of $400 U.S. for one meal. Despite careful preparation, fugu remains a common cause of fatal food poisoning in Japan, accounting for approximately 50 deaths annually (7).

Although arriving travelers are required to declare all food products brought into the United States, control measures rely primarily on the traveler. Other foodborne outbreaks in the United States have occurred after consumption of illegally imported food products (8). Persons who travel to countries where fugu is served should be aware of the potential risk of eating this fish.


  1. Halstead BW. Dangerous marine animals: that bite-sting-shock-are non-edible. Cambridge, Maryland: Cornell Maritime Press, 1959.

  2. Ellenhorn MJ, Barceloux DG. Medical toxicology: diagnosis and treatment of human poisoning. New York: Elsevier Science Publishing Company, Inc., 1988.

  3. Bradley SG, Kilka LJ. A fatal poisoning from the Oregon roughskinned newt (Taricha granulosa). JAMA 1981;246:247.

  4. Kim S. Food poisoning: fish and shellfish. In: Olson KR, ed. Poisoning and drug overdose. 2nd ed. Norwalk, Connecticut: Appleton and Lange, 1994.

  5. Gellert GA, Ralls J, Brown C, Huston J, Merryman R. Scombroid fish poisoning: underreporting and prevention among noncommercial recreational fishers. West J Med 1992;157:645-7.

  6. Anonymous. Poisindex toxicologic managements. Vol 88: tetrodotoxin. Englewood, Colorado: Micromedex, Inc., 1974-1996.

  7. Torda TA, Sinclair E, Ulyatt DB. Puffer fish (tetrodotoxin) poisoning: clinical record and suggested management. Med J Aust 1973;1:599-602.

  8. CDC. Cholera associated with food transported from El Salvador -- Indiana, 1994. MMWR 1995; 44:385-6.

Note: To print large tables and graphs users may have to change their printer settings to landscape and use a small font size.

TABLE 1. Types of food poisoning associated with naturally occurring toxins in seafoods, by selected characteristics *
Type of                                                Symptom
 poisoning   Poisoning   Source                         Onset        Clinical Syndrome
Ciguatera    Ciguatoxin  Coral reef fish,             1 to 4 hours   Abdominal pain, diarrhea
                         barracuda, red snapper,                     vomiting, cold-to-hot
                         and grouper                                 sensory reversal,
                                                                     paresthesias, myalgias,
                                                                     and weakness

Amnesic      Domoic      Mussels, clams, crabs,       15 minutes     Vomiting, diarrhea,
shellfish    acid        and anchovies                to 38 hours    headache, myoclonus,
                                                                     hemiparesis, seizures,
                                                                     coma, and permanent loss
                                                                     of short-term memory

Scombroid    Histidine   Tuna, mahi mahi, bonita,     Minutes to     Severe headache,
                         mackerel, bluefish, and      4 hours        dizziness, nausea,
                         skipjack                                    vomiting, flushed
                                                                     skin, urticaria, and

Neurotoxic   Neurotoxin  Mussels and most plankton    Minutes to     Diarrhea, vomiting,
shellfish                feeders                      3 hours        ataxia, and paresthesias

Paralytic    Saxitoxin   Mussels and clams            <=30 minutes   Vomiting, diarrhea, facial
shellfish                                                            paresthesias, and
                                                                     respiratory paralysis
* Adapted from references 4 and 5.

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