Ciguatera fish poisoning (CFP), also known asciguatera, is afoodborne illness caused by eating tropicalreef fish contaminated withciguatoxins.[4][2] Such individual fish are said to beciguatoxic. Symptoms may includediarrhea, vomiting, numbness, itchiness,dysesthesia, sensitivity to hot and cold,dizziness, and weakness with lethargy.[1][2] The onset of symptoms varies with the amount of toxin absorbed. If a large quantity of toxins is consumed, symptoms may appear within half an hour. At lower amounts, symptoms may take a few days to appear.[3] Diarrhea may last up to four days.[1] Symptoms may last a few weeks to a few months.[3] Heart problems such asslow heart rate andlow blood pressure may occur.[2]
Preventive efforts include not eating reef fish, not eating high-risk fish such as barracuda, and not eating fish liver,roe, or fish heads.[2] Ciguatoxin has no taste or smell, and cannot be destroyed by conventionalcooking.[2] There is no specific treatment for ciguatera fish poisoning once it occurs.[2]Mannitol may be considered, but the evidence supporting its use is not very strong.[1]Gabapentin oramitriptyline may be used to treat some of the symptoms.[2]
In 2017, theUnited States Centers for Disease Control (CDC) estimated that around 50,000 cases occur globally each year.[2] Other estimates suggest up to 500,000 cases per year.[1] The risk of death from poisoning is less than 1 in 1,000 according to the CDC.[2] It is the most frequentseafood poisoning.[3] It occurs most commonly in thePacific Ocean,Indian Ocean, and theCaribbean Sea between thelatitudes of 35°N and 35°S.[2] The risk of the condition appears to be increasing due to coral reef deterioration and increasing trade in seafood.[2] Descriptions of the condition date back to at least 1511.[3] The current name, introduced in 1787, is of Cuban Spanish origin and originally referred to thegastropodCittarium pica.[3]
Hallmark symptoms of ciguatera in humans includegastrointestinal, cardiovascular, andneurological effects.[5][6] Gastrointestinal symptoms includenausea,vomiting, anddiarrhea, usually followed by neurological symptoms such asheadaches, muscle aches,paresthesia, numbness of extremities, mouth and lips, reversal of hot and cold sensation,[7][8]ataxia,vertigo, andhallucinations.[9][6] Severe cases of ciguatera can also result in coldallodynia, which is a burning sensation on contact with cold.[5] Neurological symptoms can persist and ciguatera poisoning is occasionally misdiagnosed asmultiple sclerosis.[10] Cardiovascular symptoms includebradycardia,tachycardia, hypotension, hypertension, orthostatic tachycardia, exercise intolerance, and abnormal electrocardiograms.[11] Death from the condition can occur, but is very rare.[12]
Dyspareunia and other ciguatera symptoms have developed in otherwise healthy males and females followingsexual intercourse with partners suffering ciguatera poisoning, signifying that the toxin may be sexually transmitted.[13] Diarrhea and facial rashes have been reported in breastfed infants of poisoned mothers, suggesting that thepolyether toxins partition into breast milk.[14]
The symptoms can last from weeks to years, and in extreme cases as long as 20 years, often leading to long-term disability.[15] Most people do recover slowly over time.[16]
Diagnosis is based on a person's symptoms together with having recently eaten fish.[1] If a number of those who eat the same fish have symptoms the diagnosis becomes more likely.[1] If some of the fish they had previously eaten is available this can also be tested to confirm the diagnosis.[1] Other potential causes such asparalytic shellfish poisoning (PSP),neurotoxic shellfish poisoning (NSP),scombrotoxin fish poisoning, andpufferfish poisoning should be excluded.[1]
The reversal of hot and cold sensations is an occasional symptom of CFP that may help differentiate it fromnorovirus.[19]
There is no known effective treatment or antidote for ciguatera poisoning. The mainstay of treatment is supportive care. There is some evidence thatcalcium channel blockers likenifedipine andverapamil are effective in treating some of the symptoms that remain after the initial sickness passes, such as poor circulation and shooting pains through the chest. These symptoms are due tovasoconstriction caused by maitotoxin.[6][20][21][22] Ciguatoxin lowers the threshold for openingvoltage-gated sodium channels insynapses of thenervous system. Opening a sodium channel causes depolarization, which could sequentially cause paralysis, heart contraction, and changing the senses of hot and cold. Some medications such as amitriptyline may reduce some symptoms, such asfatigue and paresthesia,[23] although benefit does not occur in every case.[24]
Mannitol was once used for poisoning after one study reported symptom reversal.[6][25] Follow-up studies in animals[26] and case reports in humans[27] also found benefit from mannitol. However, a randomized,double-blindclinical trial found no difference between mannitol and normalsaline.[28] Despite this its use may still be considered.[1]
The current estimated global incidence annually is 20,000 to 50,000 people, though a large number of cases are believed to go unreported.[29]
Due to the limited habitats of ciguatoxin-producing microorganisms, ciguatera is common only insubtropical andtropical waters, particularly the Pacific and Caribbean, and usually is associated with fish caught in tropical reef waters.[5] Exportation of reef fish, as well as tourism, often account for cases that develop in other regions.[29]
Ciguatoxin is found in over 400 species of reef fish. Avoiding consumption of all reef fish is the only sure way to avoid exposure.[30] Imported fish served in restaurants may contain the toxin and produce illness which often goes unexplained by physicians unfamiliar with the symptoms of a tropical toxin.[30][31] Ciguatoxin can also occur infarm-raisedsalmon.[32] Furthermore,species substitution, labeling a reef fish as a non-reef fish at restaurants and retail, can complicate efforts by consumers to avoid ciguatera.[citation needed]
In 1994, Nobel-Prize winning novelistSaul Bellow nearly died from ciguatera after eating red snapper on vacation in St. Martin, fictionalized in his last novelRavelstein.[33]
In 2007, ten people inSt. Louis, Missouri developed the disease after eating imported fish.[34]
From August 2010 to July 2011, there were eight outbreaks of ciguatera fish poisoning in New York City. Outbreaks were linked to barracuda and grouper purchased at a fish market in Queens, New York.[36]
In the first quarter of 2012, two restaurants inLanzarote,Canary Islands are thought to have been the source of ciguatera poisoning, leading to new fishing regulations issued 18 April 2012. The first outbreak was reported in February 2012. Diners suffered with vomiting, diarrhoea and abdominal pain several hours after eating amberjack. The second case was in early April affecting six people who live in Lanzarote and had all eaten amberjack at a local restaurant.[37]
In March 2014, nine people were hospitalised nearMacksville, New South Wales, Australia after a recreational fisherman caught a 55 lb (25 kg)Spanish mackerel (Scomberomorus commersoni) offScotts Head (NSW) and then shared it among his friends and family.[38]
In April 2015, fourteen crew members of a potash ship were hospitalized in Saint John, New Brunswick, Canada after consuming tropical fish obtained from international waters.[39] After the incident, Marine Catering Services issued a reminder to seafarers that the UK Food Act makes it illegal for crews to fish for food from their vessels.[40]
In September 2016, a British holidaymaker died while on honeymoon in Mexico after consuming fish contaminated with the algae that causes ciguatera poisoning.[12]
During October 2016, more than 100 people suffered from ciguatera poisoning after eating fish heads supplied by an export firm in Mangalore, India.[41]
Researchers suggest that ciguatera outbreaks caused by warm climatic conditions in part propelled themigratory voyages of Polynesians between 1000 and 1400 CE.[43][44]
In Northern Australia, where ciguatera is a common problem, two differentfolk science methods are widelybelieved to detect whether fish harbor significant ciguatoxin. The first method is that flies are supposed not to land on contaminated fish. The second is that cats will either refuse to eat or vomit/display symptoms after eating contaminated fish.
OnGrand Cayman and other islands the locals will test barracuda by placing a piece of the fish on the ground and allowing ants to crawl on it. If the ants do not avoid the flesh and will eat it, then the fish is deemed safe.[citation needed]
In Dominican Republic, another common belief is that during months whose names do not include the letter "R" (May through August), it is not recommended to eat certain kinds of fish, because they are more likely to be infected by the ciguatera toxin.
The validity of many of these tests has been scientifically rejected.[45]
Leaves ofHeliotropium foertherianum (Boraginaceae) – also known asoctopus bush – are used in many Pacific islands as a traditional medicine to treat ciguatera fish poisoning. Senescent octopus bush leaves containrosmarinic acid and derivatives, which are known for theirantiviral,antibacterial,antioxidant, andanti-inflammatory properties.[46] Rosmarinic acid may remove the ciguatoxins from their sites of action, as well as being an anti-inflammatory.
An account of ciguatera poisoning from a linguistics researcher living onMalakula island,Vanuatu, indicates the local treatment: "We had to go with what local people told us: avoid salt and any seafood. Eat sugary foods. And they gave us a tea made from the roots of ferns growing on tree trunks. I don't know if any of that helped, but after a few weeks, the symptoms faded away".[47]
Various Caribbean folk and ritualistic treatments originated inCuba and nearby islands. The most common old-time remedy involves bed rest subsequent to aguanabana juiceenema.[citation needed] InPuerto Rico, natives drink atea made frommangrove buttons, purportedly high inB vitamins, to flush the toxic symptoms from the system.[citation needed] There has never been a funded study of these treatments. Other folk treatments range from directly porting and bleeding the gastrointestinal tract to "cleansing" the diseased with a dove during aSantería ritual.[citation needed]
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^Gillespie N, Lewis R, Pearn J, Bourke A, Holmes M, Bourke J, Shields W (1986). "Ciguatera in Australia. Occurrence, clinical features, pathophysiology and management".Med. J. Aust.145 (11–12):584–90.doi:10.5694/j.1326-5377.1986.tb139504.x.PMID2432386.
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^Lehane, Leigh; Lewis, Richard J (November 2000). "Ciguatera: recent advances but the risk remains".International Journal of Food Microbiology.61 (2–3):91–125.doi:10.1016/S0168-1605(00)00382-2.PMID11078162.
^Attaway D, Zaborsky O (1993).Marine Biotechnology. p. 8.
^Davis R, Villar L (1986). "Symptomatic improvement with amitriptyline in ciguatera fish poisoning".N. Engl. J. Med.315 (1): 65.doi:10.1056/NEJM198607033150115.PMID3713788.
^Palafox N, Jain L, Pinano A, Gulick T, Williams R, Schatz I (1988). "Successful treatment of ciguatera fish poisoning with intravenous mannitol".JAMA.259 (18):2740–2.doi:10.1001/jama.259.18.2740.PMID3128666.
^Mattei C, Molgó J, Marquais M, Vernoux J, Benoit E (1999). "Hyperosmolar D-mannitol reverses the increased membrane excitability and the nodal swelling caused by Caribbean ciguatoxin-1 in single frog myelinated axons".Brain Res.847 (1):50–8.doi:10.1016/S0006-8993(99)02032-6.PMID10564735.S2CID11662638.
^Sanders, Lisa (April 5, 2010)."Fish Tale".The New York Times. Retrieved2010-04-10. (The New York Times incorrectly gives William Anderson's first name as John.)
^Rossi, Fanny; Jullian, Valérie; Pawlowiez, Ralph; Kumar-Roiné, Shilpa; Haddad, Mohamed; Darius, H. Taiana; Gaertner-Mazouni, Nabila; Chinain, Mireille; Laurent, Dominique (2012). "Protective effect of Heliotropium foertherianum (Boraginaceae) folk remedy and its active compound, rosmarinic acid, against a Pacific ciguatoxin".Journal of Ethnopharmacology.143 (1):33–40.doi:10.1016/j.jep.2012.05.045.PMID22706150.
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