What is Ciguatera.
Ciguatera is a form of food poisoning. It is caused by eating those warm ocean water finfish that carry ciguatera poison. This poison is produced by a very tiny organism called a dinofiagellate, which attaches itself to algae growing in warm ocean water reef areas. Small plant eating fish eat this toxic algae and in turn are eaten by larger predatory fish, which end up being eaten by humans.

What type of finfish cause poisoning.
There are no specific rules that can be followed to detect ciguatera carrying fish. Fish that live in warm ocean waters are potential carriers of ciguatera toxin. Fish like chinaman, red bass and paddle tail have, in the past, been involved in a large number of ciguatera poisonings and seafood marketers sell little of them. Today problems are encountered with coral trout, spanish mackeral, red emperor, reef cods and others like wrasse, trevally and kingfish.

Who is affected.
Victims of ciguatera fish poisoning are often members of an angler's own family who eat the larger fish of the catch usually belong to a predatory species like coral trout or spanish mackeral, which live off smaller ciguatera carrying fish. Ciguatera toxin does not affect the appearance, odour or taste of fish, no matter how much is present. Processes like cooking and freezing will not destroy it and there is no known culinary method that can remove it from the fish.

What are the symptoms.
Symptoms may start one to 24 hours after ciguatera carrying fish are eaten. This will depend on how much fish is eaten, how much toxin is in the fish, and how susceptible is the consumer. Symptoms experienced may include:-

• Tingling and numbness in fingers, toes, around lips, tongue, mouth and throat burning sensation or skin pain on contact with cold water.
  
• Joint and muscle pains with weakness andlorcramps.
  
• Nausea, vomiting, diarrhoea andlor abdominal cramps.
  
• Muscular weakness, headache, fatigue and fainting.
  
• Extreme itchiness, often worsened by drinking alcohol.
  
• In severe cases difficulty in breathing.

Treatment.
Promptly seek medical attention at the first onset of symptoms so other conditions like botulism can be excluded. Also in severe cases, an intravenous infusion of mannitol may give significant relief if commenced promptly. On occasions some symptoms may last for months, but normally most will disappear within days to several weeks.

Minimising the risk.
To minimise the risk of ciguatera fish poisoning pay attention to the following precautions:-

• Ciguatera toxic fish can not be detected by appearance, odour, texture or taste.
• Ciguatera toxin will not be removed or destroyed by freezing, cooking or any other process.
• Never eat the head, roe, liver or other viscera of warm ocean water fish. Ciguatera toxin concentrates in these parts.
• Restrict eating warm ocean water fish to one meal every two weeks. This will help slow down the buildup of ciguatera toxin ina person's body.
• Avoid eating large warm ocean water fish. Limit whole weight to around six kilos per fish. Ciguatera fish poisoning occurs more when larger fish are eaten.
• When first eating a warm ocean water fish, eat a small portion only, no more than 200 grams. If tingling sensations and/or numbness develops, do not eat.
• Never mix together fillets taken from large warm ocean water fish. When selling or eating, keep fillets no more than 200 grams in weight and well separated.
• Do not catch fish from known ciguatera areas.

Recovering from ciguatera fish poisoning.
People recovering from ciguatera fish poisoning should avoid eating warm ocean water fish for at least six months. Alcohol should also be avoided for three months as this can cause ciguatera poisoning symptoms to recur. Once recovered, first eat only a small portion of fish, which is no more than 200 grams. If mild symptoms recur people should seek medical advice and avoid that fish for a few more months.

Who to contact.
More information is needed about the distribution of ciguatera fish poisoning in Australia. It is important to know what type of fish was involved and where it was caught. People experiencing or having experienced what they believe to be ciguatera fish poisoning should contact:

Tropical Public Health Unit Network.
Caims. (07) 4050 3601
Townswille. (07) 4750 4020
Mackay. (07) 4968 3858

Central Public Health Unit Network. Rockhampton. (07) 4920 6989 Wide Bay. (07) 4150 2780 Sunshine Coast. (07) 5479 4655 Redclifte. (07) 3284 8333

Southern Public Health Unit Network.
Darling Downs. (07) 4631 9888
West Moreton. (07) 3818 5001
Brisbane Southside. (07) 3000 9145
South Coas.t (07) 5509 7212

Courtesy: Queensland Health and Dept Primarv Industries.

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