The Hong Kong Centre for Health Protection (CHP) of the Department of Health is investigating a suspected ciguatera toxin poisoning cases affecting three patients.

Hong Kong/CIA
Hong Kong/CIA

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 diarrhea 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.

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.

“The toxin cannot be destroyed by cooking,” the spokesman said.