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Epidemiologic Notes and Reports Scombroid Fish Poisoning -- Illinois, South Carolina

Scombroid fish poisoning is an acute syndrome resulting from consumption of fish containing high levels of histamine. This report summarizes investigations of two outbreaks of scombroid fish poisoning in Illinois and South Carolina in 1988.

Illinois. On February 26, 1988, eight cases of scombroid fish poisoning occurred in Chicago in five patrons and three employees of a private club who had eaten a buffet lunch. Six of the ill persons experienced symptoms that included headache, nausea, flushing, dizziness, and diarrhea 90 minutes after the meal. The median duration of symptoms was 9.5 hours. Investigation by the Illinois Department of Public Health revealed that seven of the ill persons had eaten mahi mahi with dill sauce; the eighth had eaten the dill sauce scraped from the serving pan that held the fish. Three persons noted that the fish tasted "Cajun," and one stated that it had a hot or spicy taste.

The club had purchased 10.5 pounds of frozen mahi mahi from a suburban Chicago distributor the week before it was served. The distributor's records revealed that fish from one of two lots of mahi mahi had been sent to the club. On March 1, the state health department placed both lots under embargo. The lots included boxes with evidence of freezer burn, a sign of thawing and refreezing, but these boxes were held by the distributor as damaged goods and not used. The Food and Drug Administration (FDA) tested fish from 17 boxes in these lots; no fish from boxes with evidence of freezer burn were sampled. Six samples had histamine levels greater than or equal to 50 mg/ 100 g (range: 50-160 mg). The fish was kept in the club's freezer at 0-5 F (œm-15.0 C- œm-17.8 C) until February 26, when it was thawed by placing it under running water for 15 minutes. The fish was then cut into portions, placed flat in pans in the cooler, and baked as needed during lunch until the supply was depleted.

South Carolina. In September 1988, nine cases of scombroid fish poisoning in Charleston were investigated by the South Carolina Department of Health and Environmental Control. Of the nine cases, five occurred after consumption of a midday meal at a restaurant September 9, one case followed an evening meal at a second restaurant September 10, and three cases occurred after an evening meal of fish prepared at home but obtained from the first restaurant.

The median age of the nine ill persons was 55 years (range: 18-64 years); five were women. Illness occurred 5-60 minutes after the meal (median time to onset of symptoms: 38 minutes). Symptoms included flushing, diarrhea, headache, feverishness, nausea, rapid pulse, pruritus, dizziness, vomiting, facial swelling, numbness around the mouth, and stomach pain. Symptoms resolved in all persons within 10 hours (median: 6 hours). Fiv patients required emergency room treatment, and one was admitted for observation because of underlying cardiac disease.

Two persons noted that the fish had a slight peppery taste, and one person noted a metallic taste. All had eaten yellow-fin tuna supplied by the same local distributor. FDA analyses of two samples from the yellow-fin tuna revealed histamine levels of 728 mg/100 g and 583 mg/100 g, respectively.

The yellow-fin tuna were probably caught 1 day before purchase in waters off the coast of New Jersey, Rhode Island, and Virginia, and were cleaned and packed in ice on the boat. They were then obtained from docks in Cape May and Barnegat Light, New Jersey, by a regional supplier in Philadelphia 3 days before the outbreak. After purchase, the fish were repacked in ice and delivered by truck to Philadelphia, where they were divided into two lots and repacked in ice for shipment to wholesalers. They left the Philadelphia supply plant by refrigerated truck 12 hours after arrival. The wholesaler in Charleston received 188 pounds of yellow-fin tuna from the supply truck 1 day before the outbreak, processed the tuna into steaks, and shipped 17 pounds of steaks from the same fish to each of the two restaurants implicated in the outbreak. Tuna steaks from the same shipment were supplied to 12 other Charleston restaurants, all of which reported receiving the fish in ice. Both implicated restaurants kept the fish packed in ice and refrigerated before it was broiled and served to customers.

One day after the outbreak, a telephone survey of emergency rooms in the Charleston area revealed no other cases suggestive of scombroid poisoning. All restaurants that had received yellow-fin tuna supplied by the Charleston wholesaler from this shipment were notified. Reported by: LR Murray, MD, LC Edwards, MD, City of Chicago Dept of Health; RJ Martin, DVM, D Rogers, DS, CW Langkop, MSPH, CD Cuda, S Redschlag, MS, BJ Francis, MD, State Epidemiologist, Illinois Dept of Health. MD Lawhead, MD,AMI East Cooper Community Hospital, Charleston; FU Davis, RL Mackey, Charleston County Health Dept; JC Chambers, MD, Trident Public Health District; WB Gamble, MD, State Epidemiologist, South Carolina Dept of Health and Environmental Control. Food and Drug Administration. Div of Field Svcs, Epidemiology Program Office; Enteric Diseases Br, Div of Bacterial Diseases, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: During 1973-1986, 178 outbreaks of scombroid poisoning affecting 1096 persons (median: two cases/outbreak) were reported to CDC's Foodborne Disease Outbreak Surveillance System; no fatal cases were reported. Outbreaks have been reported from 30 states and the District of Columbia, with Hawaii reporting the largest number of outbreaks (51), followed by California (29), New York (24), Washington (19), and Connecticut (nine). The fish species was known in 143 (80%) of the scombroid outbreaks; the most commonly reported types were mahi mahi (66 outbreaks), tuna (42 outbreaks), and bluefish (19 outbreaks).

Scombroid poisoning is named for the family Scombridae, which includes tuna and mackerel, but this illness can occur after ingestion of any dark-fleshed nonscombroid species containing high levels of free histidine (1). When these fish are improperly refrigerated, free histidine is broken down to histamine by surface bacteria. This latter compound is thought to produce the clinical manifestations of illness (2); hence, some investigators have termed this syndrome histamine poisoning (2).

Illness begins minutes to hours after ingestion of the toxic fish. Symptoms resemble a histamine reaction and frequently include dizziness, headache, diarrhea, and a burning sensation or peppery taste in the mouth. Facial flushing, tachycardia, pruritus, and asthma-like symptoms can also occur. Illness is usually mild and duration is short, making treatment unnecessary. For more severe cases or in patients with underlying medical conditions, oral antihistamines may be beneficial (3). Intravenous cimetidine has been anecdotally reported to ameliorate symptoms but its use warrants further study (4).

Scombroid poisoning is diagnosed by history and clinical symptoms combined with the measurement of histamine levels in implicated fish. Fresh fish normally contains less than 1 mg/100 g of histamine; levels of 20 mg/100 g in some species have been reported to produce symptoms (5). The FDA has established 50 mg/100 g of histamine as a hazardous level in tuna (6), a level exceeded in both outbreaks in this report. Investigation failed to reveal evidence of improper storage. Experimental studies indicate that histamine formation is low at refrigerator temperatures and negligible in fish stored at less than or equal to 32 F (less than or equal to 0 C) (2). As these outbreaks demonstrate, cooking toxic fish is not protective. Therefore, the key to prevention of scombroid poisoning is continuous icing or refrigeration of all potentially scombrotoxic fish from the time they are caught until they are cooked.


  1. Etkind P, Wilson ME, Gallagher K, Cournoyer J, Working Group on Foodborne Illness Control. Bluefish-associated scombroid poisoning: an example of the expanding spectrum of food poisoning from seafood. JAMA 1987;258:3409-10. 2.Taylor SL. Histamine food poisoning: toxicology and clinical aspects. CRC Crit Rev Toxicol 1986;17:91-128. 3.Hughes JM, Merson MH. Fish and shellfish poisoning. N Engl J Med 1976;295:1117-20. 4.Blakesley ML. Scombroid poisoning: prompt resolution of symptoms with cimetidine. Ann Emerg Med 1983;12:104-6. 5.Bartholomew BA, Berry PR, Rodhouse JC, Gilbert RJ, Murray CK. Scombrotoxic fish poisoning in Britain: features of over 250 suspected incidents from 1976 to 1986. Epidemiol Infect 1987;99:775-82. 6.Food and Drug Administration. Defect action levels for histamine in tuna; availability of guide. Federal Register 1982;47:40487.

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