Press Release

CHP investigates suspected ciguatoxin poisoning case

25 April 2016

The Centre for Health Protection (CHP) of the Department of Health is today (April 25) investigating a suspected ciguatoxin poisoning case affecting three patients.

The case involves three females aged from 43 to 80. Two patients developed symptoms of ciguatoxin poisoning including lip and limb numbness, weakness, dizziness and diarrhoea about four to seven hours after having self-prepared fish slices at workplace on April 18.

Another woman developed similar symptoms immediately after eating the same self-prepared fish slices at home on the same day.

All sought medical attention and one was admitted to Ruttonjee Hospital and she had already been discharged. All are now in a stable condition.

The CHP's investigations are ongoing.

"We have alerted the Food and Environmental Hygiene Department to the incident," a spokesman for the CHP said.

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 whether it contains the toxin.

People affected may show symptoms of numbness of the mouth and the limbs, vomiting, diarrhoea, alternating sensations 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 toxins are 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 toxins;
• 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.