The Centre for Health Protection is investigating two suspected ciguatoxin poisoning cases affecting three people who ate marine fish.

A 40-year-old woman came down with numbness, diarrhoea and fatigue seven hours after eating fish at home on March 20. She has been discharged from Yan Chai Hospital and is stable.

Another woman, 30, and a man, 32, came down with similar symptoms on March 19. Both sought medical treatment from a private doctor and are stable.

The centre found the fish were bought from stalls in Tung Chung and Fanling markets.

Ciguatera fish poisoning is not uncommon in tropical areas. It is mainly associated with the consumption of big coral reef fish which have accumulated the toxin in their bodies. Larger fish are more likely to carry higher amounts of toxin which cannot be destroyed through cooking.

Most people affected will recover without long-term health effects. However, if excessive toxin is consumed, the circulatory and nervous systems will be affected.