Scombroid on the menu

I'm at the beach and as you might expect there are a lot of seafood restaurants. While I'm not a big fish eater, I do appreciate the really neat kinds of food poisoning you can get from fish. Like scombroid:

Scombroid fish poisoning is an acute illness that occurs after eating fish containing high levels of histamine or other biogenic amines. Symptoms typically include facial flushing, sweating, rash, a burning or peppery taste in the mouth, diarrhea, and abdominal cramps and usually resolve within several hours without medical intervention. More severe symptoms (e.g., respiratory distress, swelling of the tongue and throat, and blurred vision) can occur and require medical treatment with antihistamines. (CDC MMWR)

Unlike most other kinds of food poisoning, scombroid happens quickly, often within 30 minutes of eating the meal (it has this in common with ciguatera poisoining, another fish syndrome). The CDC note excerpted above is from an outbreak investigation of two scombroid episodes, one in Lousianna and one in Tennessee. Both came from tuna steaks originating countries familiar to the bird flu obsessed, Indonesia (Louisianna) and Vietnam (Tennessee), a reflection of the fact that most seafood we eat in this country is imported (although where I am at the moment, it is fresh off the boats I see offshore). Most of that seafood is not inspected. CDC says that of8500 firms importing seafood in 2002 - 2003, only 5 - 7% were inspected.

Scombroid poisoning is from "histamine and biogenic amines," meaning small molecules manufactured by bacteria during improper fish storage. That is why it manifests so quickly: you are ingesting biologically active chemicals, not being infected by bacterial organisms (as in salmonella). Thus the way to prevent scombroid is keeping freshly caught fish at refrigerator temperatures until it is served. Dead fish sitting on the dock for hours at a time are the grounds for scombroid, although it happens fairly rarely. But for your entertainment, here are the CDC accounts of each outbreak:

Louisiana. On December 14, 2006, six employees of an oil refinery ate at the company cafeteria and became ill with symptoms resembling an allergic reaction within 2 hours of eating tuna steaks. The refinery nurse notified the Louisiana Office of Public Health, and an epidemiologic investigation was initiated to identify the source of the outbreak and implement control measures. Four refinery employees went to the infirmary with facial flushing and pruritic rashes on the face, neck, and trunk and reported heart palpitations and diarrhea after eating tuna steak in the cafeteria. Median time from eating to onset of symptoms was 1 hour (range: 15 minutes--2 hours). On the basis of clinical symptoms and seafood exposure, scombroid fish poisoning was suspected, and the remaining tuna steaks were immediately removed from the cafeteria line. A facilitywide announcement resulted in identification of two additional cases. Five of the patients were treated with diphenhydramine and loperamide at the refinery infirmary, and one patient was treated with diphenhydramine at a local hospital emergency department.

[snip]

Tennessee. On November 25, 2006, five persons became ill after eating tuna steaks at one restaurant. Symptoms included skin rash (two persons), headache (two), diarrhea (three), and abdominal cramping (three), with onset occurring 35--150 minutes after tuna consumption. The index patient experienced skin rash and headache 35 minutes after eating tuna. This patient was treated at a local emergency department with antihistamine intravenously, which led to rapid resolution of symptoms. Illness in the other five persons resolved without medical intervention. The physician treating the index patient notified public health officials and the restaurant, and the restaurant immediately stopped serving the implicated fish. (CDC MMWR)

Scombroid gets its name from the family of fish most often implicated, the Scombridae, which includes tuna and mackerel, both with high levels of muscle histidine which gets converted to histamine. Other fish may be involved, too, including mahi mahi, amberjack, bluefish, abalone, and sardines. I don't like oily fish but I do eat mahi mahi and tuna, so someday I might get it, too. But probably not, It's pretty rare, accounting for less than a half percent of food poisonings. It's probably underreported, like all food poisonings, although full blown scombroid is pretty dramatic and can result in a quick trip to the emergency room.

I just asked Mrs. R. what was on the menu tonight and she said she hadn't decided but it was either chicken, sausage, eggs or pasta. No fish. No scombroid. Maybe another night.