Ciguatera fish poisoning

Twenty cases of ciguatera fish poisoning from consumption of amberjack were reported to the Florida Department of Health and Rehabilitative Services (HRS) in August and September 1991. This report summarizes the investigation of these cases by the Florida HRS.

On August 9, the Florida HRS was notified of eight persons who developed one or more of the following symptoms: cramps, nausea, vomiting, diarrhea, and chills and sweats within 3-9 hours (mean: 5 hours) after eating amberjack at a restaurant on August 7 or August 8; duration of symptoms was 12-24 hours. Three persons were hospitalized. By August 12, patients began to report pruritus of the hands and feet, paresthesia, dysesthesia, and muscle weakness. Based on initial food histories, the Florida HRS suspected consumption of amberjack as the source of illness. On August 14, three additional persons with similar symptoms who also had eaten amberjack at the restaurant on August 8 were reported.

Results of cultures of stool and vomitus samples from the hospitalized persons were negative for Salmonella, Shigella, Campylobacter, and Yersinia. No cooked amberjack was available from the same lot from the restaurant for further testing. Although minor sanitation and safety violations were observed at the restaurant, they did not appear related to the outbreak. Because of the unique symptomology and common denominator of amberjack, investigators suspected either scombroid or ciguatera poisoning.

The shipment of amberjack was traced to a seafood dealer in Key West, Florida, who had distributed the fish through a dealer in north Florida. The second dealer subsequently had sold the fish to the restaurant, another restaurant in Alabama, and a third dealer who sold the fish to two grocery stores in Alabama and north Florida. On August 20 and on September 20, the Florida HRS received reports of additional suspected cases among persons who had bought amberjack at the Alabama grocery store (six persons) and at the grocery store in north Florida (three), respectively.

The Food and Drug Administration evaluated 19 amberjack samples believed to have originated from a single lot from the Key West dealer and obtained from restaurants and grocery stores in Florida and Alabama for ciguatera-related toxin. Forty percent of the specimens tested by mouse bioassay were positive for ciguatera-related biotoxins.

Reported by: RM Hammond, PhD, Office of Restaurant Programs, RS Hopkins, MD, State Epidemiologist, Florida Dept of Heaht and Rehabilitative Svcs. R Dickey, PhD, Div of Seafood Research, Food and Drug Administration, Dauphin Island, Alabama. Scientific Information and Communications Program, Office of the Director, Epidemiology Program Office, CDC.

Editorial Note: Ciguatera is a naturally, sporadically occurring fish toxin that affects a wide variety of popularly consumed reef fish; ciguatera becomes more bioconcentrated as it moves up the food chain. Ciguatera and related toxins are derived from dinoflagellates, which herbivorous fish consume while foraging through macro-algae [1]. Large predator reef fish (e.g., barracuda, grouper, amberjack, surgeon fish, sea bass, and Spanish mackerel) have been implicated in previouls outbreaks [2,3].

Humans ingest the toxin by consuming either herbivorous fish or carnivorous fish that have eaten contaminated herbivorous fish [4,5]. The toxin is tasteless, and because it is heat-stable, cooking does not render the fish safe for consumption. As in this outbreak, ciguatera fish poisoning is diagnosed by the characteristic combination of gastrointestinal and neurologic symptoms in a person who eats a suspected fish [6,7]. The diagnosis is supported by detection of ciguatoxin in the implicated fish. No specific, effective treatment for ciguatera fish poisoning has been proven; supportive treatment is based on symptoms [4,7].

Further study of seafood toxins is required to develop routine detection tests for the fishing industry, diagnostic tests to evaluate clinical cases, and effective treatment for persons who ingest ciguatera toxins.

References

[1.] Bagnis R, Chanteau S, Chungue E, Hurtel JM, Yasumoto T, Inoue A. Origins of ciguatera fish poisoning: a new dinoflagellate, Gambierduscis toxicus Adachi and Fukuyo, definitively involved as a causal agent. Toxicon 1980;18:199-208.

[2.] CDC. Ciguatera fish poisoning--Bahamas, Miami. MMWR 1982;31:391-2.

[3.] Craig CP. It's always the big ones that should get away [Editorial]. JAMA 1980;244:272-3.

[4.] Monis JG Jr, Lewin P, Smith CW, Blake PA, Schneider R. Ciguatera fish poisoning: epidemiology of the disease on St. Thomas, U.S. Virgin Islands. Am J Trop Med Hyg 1982;31:574-8.

[5.] Halstead BW. Class osteicthyes: poisonous ciguatoxic fishes. In: Halstead BW. Poisonous and venomous marine animals of the world. Princeton, New Jersey: Darwin Press, Inc, 1978: 325-402.

[6.] Hughes JM, Merson JH. Fish and shellfish poisoning. N Engl J Med 1976;295:1117-20.

[7.] Baldy L. 1992 Ciguatera. Florida Journal of Environmental Health 1992;137:10-3.

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