It is estimated that ciguatera food poisoning affects 25,000 people worldwide each year. It is known that ciguatoxin is produced by Gambierdiscus toxicus, a dinoflagellate associated with coral reefs, but the causative species of fish passing accumulated levels of the toxin onto humans is rarely identified (only ever twice previously). In this paper the authors are able to identify the species of fish which caused a food-poisoning outbreak in Taiwan, September 2008.
The toxin and its related compounds are usually amassed by herbivorous fishes and then passed via the food chain to carnivorous fishes, then onto humans. When ingested by humans the side effects include pricking of the lips, tongue and throat, vomiting, abdominal cramps, diarrhoea, headache, dizziness, vertigo and paralysis.
In September, 2008, a food-poisoning incident happened after people ate meat from an unidentified red-snapper species. My means of a mouse assay ciguatera toxicity samples from the incident were detected. Six commonly found red-snapper species in Taiwan were investigated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques to clearly identify the causative species.
In the low molecular weight region of the sarcoplasmic protein bands (<30.0 kD) (as identified by SDS-PAGE) specific bands from each species were observed. The patterns from the poisonous sample were the same as pattern from the snapper species Lutjanus bohar.
The authors talk about previous research in their conclusion; it has been found that small coral fish do not usually have a high content of toxicity, and that toxin accumulation is usually higher in viscera (internal organs) than in the muscle. Because at present there is no reliable prevention from ciguatera food poisoning, it is recommended that only L. bohar with a weight of less than 1kg should be consumed by humans, and even then, only the muscle, not the viscera. It is also pointed out that to decreases the number of humans affected by this; more research into the toxicity of L. bohar in Taiwan (and indeed worldwide) needs to be carried out.
The main point I understood from this short, yet information-loaded paper was the identification of the species of fish which caused a food-poisoning outbreak. No solutions were offered as to how to combat the problem. Perhaps now further research will happen investigating the toxicity of L. bohar and other coral reef fish, as it clearly impacts and affects a large number of humans throughout the tropics and sub-tropics.
A review of:
Lin, W. F., Lyu, Y. C., Wu, Y. J., Lu, C. H. and Hwang, D. H. (2012) Species identification of snapper: A food poisoning incident in Taiwan. Food Control 25 511-515.
The toxin and its related compounds are usually amassed by herbivorous fishes and then passed via the food chain to carnivorous fishes, then onto humans. When ingested by humans the side effects include pricking of the lips, tongue and throat, vomiting, abdominal cramps, diarrhoea, headache, dizziness, vertigo and paralysis.
In September, 2008, a food-poisoning incident happened after people ate meat from an unidentified red-snapper species. My means of a mouse assay ciguatera toxicity samples from the incident were detected. Six commonly found red-snapper species in Taiwan were investigated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques to clearly identify the causative species.
In the low molecular weight region of the sarcoplasmic protein bands (<30.0 kD) (as identified by SDS-PAGE) specific bands from each species were observed. The patterns from the poisonous sample were the same as pattern from the snapper species Lutjanus bohar.
The authors talk about previous research in their conclusion; it has been found that small coral fish do not usually have a high content of toxicity, and that toxin accumulation is usually higher in viscera (internal organs) than in the muscle. Because at present there is no reliable prevention from ciguatera food poisoning, it is recommended that only L. bohar with a weight of less than 1kg should be consumed by humans, and even then, only the muscle, not the viscera. It is also pointed out that to decreases the number of humans affected by this; more research into the toxicity of L. bohar in Taiwan (and indeed worldwide) needs to be carried out.
The main point I understood from this short, yet information-loaded paper was the identification of the species of fish which caused a food-poisoning outbreak. No solutions were offered as to how to combat the problem. Perhaps now further research will happen investigating the toxicity of L. bohar and other coral reef fish, as it clearly impacts and affects a large number of humans throughout the tropics and sub-tropics.
A review of:
Lin, W. F., Lyu, Y. C., Wu, Y. J., Lu, C. H. and Hwang, D. H. (2012) Species identification of snapper: A food poisoning incident in Taiwan. Food Control 25 511-515.
2 comments:
Hi Rachel
Very current paper on fish born pathogens. You mentioned that the fish species that passed ciguatoxin to humans have been identified only twice before this study. Do you know what thosoe two species were? Were they carnivorous fish too? Do the authors know at what sort of concentration the toxin needs to be inside the fish to cause disease in humans when consumed?
Hi Lee,
I’m sorry it has taken me so long to reply, it feels like there’s not enough time in the day!
In the two previously identified cases the causative fish species were moray eel Gymnothorax javanicus (Tsai et al., 2008) and for a second time, the red snapper Lutjanus bohar (Chen et al., 2010). So yes, also carnivorous fish species.
As for the concentration of toxin needed to affect humans, I’m not sure of the answer, the authors give no indication. I would however made an informed guess that since only one death had occurred since 10 outbreaks from 1991, that increased toxin concentrations lead to more severe symptoms.
I’ve just posted a new blog entry about bacterial indicators of sewage pollution. It was about using E. coli for indicating presence of hepatitis A virus – I wonder what Graham would say about that, as he seemed to think it was silly using a bacterial indicator for a virus (which I can only agree with!). Take a look at it and let me know what you think.
References:
Chen, T. Y., Chen, N. H., Lin, W. F., Hwang, K. L., Huang, Y. C. and Hwang, D. F. (2010) Identification of causative fish for food poisoning in Taiwan by using SDS-PAGE technique. Journal of Marine Science and Technology 18(4) 936-942.
Tsai, W. L., Chen, H. M., Hseih, C. H., Lin, W. F. and Hwang D. F. (2008) A potential methodology for differentiation of ciguatoxin-carrying species of moray eel. Food Control 20(6) 575-579.
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