Poison alert on imported fish

A health warning has been issued against eating imported fish because of the risk of the tropical fish toxin that causes ciguatera poisoning.

Ciguatera can cause vomiting, diarrhoea, cramps, weakness, reversal of the normal sense of cold and hot, high blood pressure, paralysis, and sometimes coma and death.

It is usually found in Pacific Islands fish.

The Auckland District Health Board said the latest case of ciguatera poisoning involved a family that imported their own fish from Fiji.

Four of the family experienced difficulty walking, had numbness and tingling lips, hands and legs, itchy skin and joint pain.

The board said tropical marine fish which contained the cigua toxin were not normally found in waters below 35 deg south, and that meant any cases of poisoning were most likely to be linked to eating imported fish.

Some restaurants offered speciality dishes containing rare, imported fish.

There are no laboratory tests that can confirm ciguatera poisoning in humans.

Diagnosis is based on the type of fish consumed and the symptoms.

Cooking or freezing does not not destroy the toxin, which accumulates in larger reef fish.

There is no treatment but symptoms usually subside in a few days and in rare cases, weeks or months.

The board warned against selling or eating tropical fish weighing more than 2.5kg, and importing species such as grouper, sea bass, barracuda, snapper, mackerel and coral trout.

In a food safety brochure, it said internal organs of the fish should not be eaten.

If the poisoning symptoms developed, the leftover fish should be kept for analysis.

- NZPA