Ciguatera
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| ICD-10 | T61.0 |
|---|---|
| ICD-9 | 988.0 |
Ciguatera is a foodborne illness poisoning in humans caused by eating marine species whose flesh is contaminated with a toxin known as ciguatoxin, which is present in many micro-organisms (particularly, the micro-algae Gambierdiscus toxicus) living in tropical waters. Like many naturally and artificially occurring toxins, ciguatoxin accumulates in lower-level organisms, resulting in higher concentration of the toxin at higher levels of the food chain, an example of biomagnification[1]. Predator species near the top of the food chain in tropical waters, such as barracuda, moray eel, parrotfish, grouper and amberjack, are most likely to cause ciguatera poisoning, although many other species have been found to cause occasional outbreaks of ciguatera. Ciguatoxin is very heat-resistant, so ciguatoxin-laden fish cannot be detoxified by cooking.
Due to the localized nature of the ciguatoxin-producing micro-organisms, ciguatera illness is only common in tropical waters, particularly the Caribbean, and usually is associated with fish caught in tropical reef waters.
The symptoms of ciguatera are gastrointestinal distress (nausea, vomiting) followed by neurological symptoms such as headaches, muscle aches, numbness, ataxia, and hallucinations. Severe cases of ciguatera can also result in hot-cold reversal, in which hot and cold sensations seem reversed.
Ciguatera toxin poisoning is frequently misdiagnosed as Multiple Sclerosis. The relapse/remit characteristic of the disease can be tied to the consumption of nuts, alcohol, fish or fish-containing products, or exposure to fumes such as those of bleach and other chemicals. Exercise is also a possible trigger.
Hallmark symptoms of ciguatera include memory loss, muscle weakness, numbness, and extreme fatigue. Doctors are often at a loss to explain these symptoms, but for the victim of this neuro-toxin poisoning, avoidance of certain foods, alcohol, and any extreme physical exertion are extremely important, and can, in fact, prevent a relapse of symptoms. A complete listing of foods to avoid are listed in the Annals of Emergency Medicine.
Ciguatoxin is found in over 400 species of reef fish, and therefore avoidance of consumption of all reef fish (any fish living in warm tropical waters) is the only sure way to avoid exposure to the toxin. Imported fish served in restaurants have been found to contain the toxin and result in illness which often goes unexplained by physicians unfamiliar with a tropical toxin and its characteristic symptoms. In addition, ciguatoxin has been found in farmed raised salmon. The symptoms can last from weeks to years, and in extreme cases lasting as many as 20 years, again in a relapse/remit pattern based on exposures to triggering foods and activities.
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[edit] History
Originally, ciguatoxin was linked to poison passed to tropical fish through consumption. However, the exact source of the toxin was unknown, and many sources were identified as the culprit. Some of these included the manchineel fruit, cocculus berries, palolo worms, compounds containing copper, pumice, corallina opuntia. As an extreme explanation, some scientists linked the passing on of toxicity to moonlight or stars.[citation needed]
In Northern Australia, where ciguatera is a common problem, there are two commonly believed ways of determining that fish carry significant levels of ciguatoxin. The first belief is that if a piece of fish is contaminated with the toxin, flies will not land on it. The second belief is that the toxin can be detected by feeding a piece of fish to a cat as cats are allegedly highly sensitive to ciguatoxin and will display symptoms. It is not known whether there is any veracity to either belief.
[edit] Etymological Roots
It is a generally held theory that ciguatera, as a poisonous substance, was named and identified in Cuba, circa early 1800's. Local folklore has identified the etymology stems from a story of an Englishman who caught a barracuda on the Isla de Pinos. After consuming the barracuda, said Englishman became terribly ill. When queried about the origins of his illness, the Englishman claimed to have caught and eaten “a fish, from the seawater.” It is the poor interpretation of the word seawater that allegedly gives the ailment the name ciguatera, or “from the seawater” in Spanish.
[edit] Treatment
The most effective treatment for ciguatera poisoning is prompt intravenous mannitol, at a dosage of 1 gram per kilogram of body mass. An initial study resulted in a majority of patients relieved of all symptoms. Later research suggests that mannitol is most effective when administered within 72 hours of exposure. If not there is a greater chance that the disease will have a greater effect.
Amitriptyline and similar medications may reduce some symptoms of Ciguatera, such as fatigue and paresthesias. Also used are steroids and vitamin supplements, but these merely support the body's recovery rather than directly reduce the toxic effects.
It should be noted that there are a number of antiquated Caribbean homeopathic treatments, as well as ritualistic ones, most of which originated from Cuba and nearby islands. The most common old-time remedy involves bed-rest subsequent to a Guanavana juice enema. Some more avant-garde old-time treatments ranged from directly porting and bleeding the gastrointestinal tract, to ‘cleansing’ the diseased with a dove during a Santeria ritual.
The efficacy of these treatments have never been studied or substantiated; nevertheless they are purportedly still used to this day.
[edit] See also
- algal bloom (see "toxic chemicals" in paragraph 2)
- dinoflagellate (see "neurotoxins" and "red tide" under Ecology and fossils and see "phosphate" under Cautions)
- paralytic shellfish poisoning (PSP)
- red tide
[edit] References
- Ciguatera fish poisoning CDC
- Ciguatera fish poisoning—Florida, 1991. MMWR June 4, 1993;42(21):417-8
- Ciguatera fish poisoning—Texas, 1997. MMWR August 28, 1998;47(33):692-4
- Epidemiologic notes and reports ciguatera fish poisoning—Bahamas, Miami. MMWR July 23, 1982;31(28):391-2
- Epidemiologic notes and reports ciguatera fish poisoning—Vermont. MMWR April 25, 1986;35(16):263-4
- Ciguatera fish poisoning
- The Ciguatera Homepage
