Published Date: 2012-03-29 13:43:25
Subject: PRO/AH/EDR> Ciguatera fish poisoning - China: (HK)
Archive Number: 20120329.1084658
CIGUATERA FISH POISONING - CHINA: (HONG KONG)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Tue 27 Mar 2012
Source: Hong Kong Department of Health [edited]
The Centre for Health Protection (CHP) of the Department of Health is today, 27 Mar 2012, investigating ciguatoxin poisoning cases affecting 5 people who have consumed coral reef fish.
The 1st episode involved 3 women and a man, aged between 20 and 56, who developed symptoms of ciguatoxin poisoning including abdominal pain, limb numbness, and diarrhea between 2 to 10 hours after eating a fish during dinner at home on 23-24 Mar 2012. One of them sought medical treatment at Pamela Youde Nethersole Eastern Hospital and required hospitalization. All are now in stable condition. Investigation revealed that the fish was purchased from a market in Ap Lei Chau on 23 Mar 2012.
The other episode involved a woman aged 48. She developed symptoms of ciguatoxin poisoning including diarrhea, numbness over face and limbs, reversal of sensation of coldness and hotness, and headache 3 hours after eating a fish at home at midnight of 26 Mar 2012. She sought medical consultation at United Christian Hospital but did not require hospitalization. She is currently in stable condition. Investigation revealed that the fish was purchased from a market in Tai Po on 24 Mar 2012.
A CHP spokesman said ciguatera fish poisoning is not uncommon in tropical areas. It is mainly associated with the consumption of big coral reef fish that have accumulated the toxin in the body, in particular in internal organs, through eating small fish that consumed toxic algae in coral reef seas. A larger fish is therefore more likely to carry higher amounts of the toxin. However, it is not easy to tell from the appearance of the fish if it contains toxin.
People affected may show symptoms of numbness of the mouth and the limbs, vomiting, diarrhoea, reversal of sensation of coldness and hotness, and pain in the joints and muscles.
The spokesman said that most people affected by ciguatoxin would recover without long-term health effects. However, if excessive toxin is consumed, the circulatory and nervous systems can be affected. "The toxin cannot be destroyed by cooking," the spokesman said.
To prevent ciguatera fish poisoning, members of the public should observe the following measures:
- Eat less coral reef fish;
- Eat small amounts of coral reef fish at any one meal and avoid having a whole fish feast in which all the dishes come from the same big coral reef fish;
- Avoid eating the head, skin, intestines, and roe of coral reef fish, which usually have a higher concentration of toxin;
- When eating coral reef fish, avoid consuming alcohol, peanuts, or beans as they may aggravate ciguatoxin poisoning;
- Seek medical treatment immediately should symptoms of ciguatoxin fish poisoning appear; and
- Coral reef fish should be purchased from reputable and licensed seafood shops. Do not buy the fish when the source is doubtful.
[The following is taken from CDC: Cluster of ciguatera fish poisoning - North Carolina, 2007. MMWR 2009; 58: 283-5
(http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5811a3.htm) (original citation numbering retained):
Ciguatoxins are lipid-soluble cyclic polyether compounds and are the most potent sodium channel toxins known (3). Carnivorous tropical and semitropical fish, such as barracuda, amberjack, red snapper, and grouper, become contaminated with ciguatoxins by feeding on plant-eating fish that have ingested _Gambierdiscus toxicus_ or another member of the _Gambierdiscus_ genus, a group of large dinoflagellates commonly found in coral reef waters (4). Gambiertoxins from _Gambierdiscus_ spp. are converted into more potent lipid-soluble ciguatoxins. Spoilage of fish that have been caught is not a factor in toxin development, and cooking does not deactivate the toxin. Humans who eat contaminated predatory fish are exposed to variable concentrations of ciguatoxin, depending on the fish size, age, and part consumed (toxins concentrate more in the viscera, especially liver, spleen, gonads, and roe). The attack rate can be as high as 80 to 90 percent in persons who eat affected fish, depending on the amount of toxin in the fish.
Persistence or recurrence of neurologic symptoms are hallmarks of CFP [ciguatera fish poisoning]. 3 of the 9 patients in this cluster had recurrences of one or more symptoms for more than 6 months after their initial illness. If these patients are again exposed to fish (either ciguatoxin-contaminated or even noncontaminated fish), their symptoms likely will be more severe than those experienced with their initial episodes of CFP (3).
Variations in the geographic distribution of the various ciguatoxins might explain regional differences in symptom patterns. CFP symptoms associated with eating fish from the Pacific Ocean are primarily neurologic, and symptoms associated with eating fish from the Caribbean Sea are more commonly gastrointestinal (4). Amberjack often is linked to CFP cases in the Caribbean. Although the amberjack fish responsible for this cluster of CFP cases tested positive for C-CTX-1, it was not tested for the presence of other ciguatoxins, which also might have been present and could have altered disease presentation (7).
CFP has been associated almost exclusively with eating fish caught in tropical or semitropical waters, but increased global marketing of these species has increased the possibility that persons in temperate zones might become ill with CFP (4). Moreover, warming seawaters might expand the ranges of ciguatoxin-contaminated fish (8). In the USA, such fish have been found as far north as the coastal waters of North Carolina. Despite underreporting, CFP now is considered one of the most common illnesses related to fish consumption in the United States (9).
Any level of Caribbean ciguatoxin 0.1 ppb or more of fish tissue is thought to pose a health risk (3). As this illness becomes more common in nontropical areas of the world, clinicians need to be aware of its manifestations and how to manage it. Although opinions vary on the most effective course of treatment, intravenous mannitol has been a mainstay of management of neurologic symptoms for more than 20 years. Early mannitol treatment is considered more effective, but anecdotal evidence suggests that even delayed therapy benefits some patients. Amitriptyline also has been useful in relieving some of the neurologic symptoms of CFP (10). If evaluating a possible case, clinicians should consult their local poison control center for the latest treatment guidelines.
3. Pearn J: Neurology of ciguatera. J Neurol Neurosurg Psychiatry 2001; 70(1): 4-8 [available at http://jnnp.bmj.com/content/70/1/4.long].
4. Lewis RJ: The changing face of ciguatera. Toxicon 2001; 39(1): 97-106 [abstract available at http://www.ncbi.nlm.nih.gov/pubmed/10936626].
5. Lange WR, Lipkin KM, Yang GC: Can ciguatera be a sexually transmitted disease? Clin Toxicol 1989; 27(3): 193-7 [abstract available at http://www.ncbi.nlm.nih.gov/pubmed/2810444].
7. Lewis RJ, Jones A: Characterization of ciguatoxins and ciguatoxin congeners present in ciguateric fish by gradient reverse-phase high-performance liquid chromatography/mass spectrometry. Toxicon 1997; 35(2): 159-68 [abstract available at http://www.ncbi.nlm.nih.gov/pubmed/9080572].
8. Chateau-Defat ML, Chinain M, Cerf N, et al: Seawater temperature, _Gambierdiscus_ spp. Variability and incidence of ciguatera poisoning in French Polynesia. Harmful Algae 2005; 4: 1053-62 [abstract available at http://www.ilm.pf/node/1356].
9. CDC: Surveillance for foodborne-disease outbreaks - United States, 1998-2002. MMWR 2006; 55(SS-10): 1-34 [available at http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5510a1.htm].
10. Lewis R, Ruff T: Ciguatera: ecological, clinical, and socioeconomic perspectives. Crit Rev Environ Sci Technol 1993; 23(2): 137-56 [abstract available at http://www.tandfonline.com/doi/abs/10.1080/10643389309388447]. - Mod.LL
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