Surveillance of marine fish for ciguatera toxin at fish markets in Bangkok, Thailand

Background: Ciguatera intoxication is a form of food poisoning. It is caused by the consumption of certain warm-water fish that have accumulated ciguatera toxin (CTX) through the marine food chain. Ciguatera fish poisoning (CFP) is a global disease, which although common, has been largely ignored in Thailand. This may be attributed to lack of confirmatory tests and seemingly nonspecific clinical presentations.

Objective: We studied CTX contamination in marine fish sold at Bangkok markets.

Methods: A surveillance of CTX in fish using the Cigua-Check assay has been conducted in Bangkok, the center of seafood marketing in Thailand. Here, there are several types of fish. Some come from domestic fishing and others are imported from Indonesia, Myanmar, or India.

Results: A random survey at three fish markets in Bangkok revealed two samples possibly contaminated with ciguatera toxin from a total 227 fish samples (of 21 fish species). This is the first report of finding CTX contamination in fish meat sold in Bangkok.

Conclusion: It is possible that these CTX-positive fish were caught from other countries. Even though the positivity (0.88%) is lower when compared with studies of other endemic areas (5.0% in Hawaii and Pacific Islands), this finding should raise awareness of the possibility of facing rare CFP intoxication from fish obtained at local Thai markets.