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The Centre for Health Protection (CHP) of the Department of Health today (June 1) is investigating two suspected ciguatoxin poisoning cases affecting four people who have consumed coral reef fish. Notification was received today following four similar reports received yesterday.
The first case involved a man and a woman aged 45 and 39, respectively. They developed symptoms of ciguatoxin poisoning including dizziness, mouth and limb numbness, weakness, abdominal pain and diarrhoea about one to five hours after eating a fish during dinner at home on May 29.
One of them sought medical treatment at North District Hospital, but no hospitalisation was required. Both of them are now in stable condition.
Investigation revealed that the incriminated coral reef fish was purchased from the same market in Sheung Shui involved in the clusters of ciguatoxin poisoning that were reported yesterday.
The second case involved a man and a woman aged 64 and 59, respectively. They developed symptoms of ciguatoxin poisoning including mouth and limb numbness, vomiting, abdominal pain and diarrhoea about one to nine hours after eating a fish during dinner at home on May 31.
They sought medical treatment at Queen Mary Hospital. One of them was admitted in stable condition while the other one did not require hospitalisation.
Investigation revealed that the incriminated fish was purchased from a wet market in Aberdeen.
A CHP spokesman said ciguatera fish poisoning is not uncommon in tropical areas. It is mainly associated with the consumption of a big coral reef fish that has accumulated the toxin in its body, in particular in internal organs, through eating small fish that consumed toxic algae in coral reef seas.
The 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 the 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 was consumed, the circulatory and nervous systems would 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.
Ends/Wednesday, June 1, 2011
Issued at HKT 19:50
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