Authorities in the British Virgin Islands have issued a warning after a surge in Ciguatera fish poisoning (CFP) within the past few weeks.

Cases until the week of June 6 were sporadic, but within three weeks there have been eight confirmed infections with other suspected cases also being investigated.

National Epidemiologist Harmony Massiah said CFP is not uncommon in tropical and sub-tropical areas and is mainly associated with consumption of big coral reef fish like snapper, bass and perch that have accumulated ciguatoxin in the body.

Larger fish will have higher amounts of the toxin. Contaminated fish cannot be identified by appearance and the toxin cannot be destroyed by cooking or freezing.

Massiah advised people to not buy fish when their source is doubtful. They should avoid eating the head, skin, intestines and roe of coral reef fish, which usually have a higher concentration of toxins, and when eating coral reef fish, avoid alcohol, peanuts or beans as they may magnify illness.

Symptoms of ciguatoxin poisoning include itchiness, diarrhea, numbness of the hands and lips, weakness and abdominal pain. onset usually occurs within six hours of eating the contaminated product and lasts a few days or weeks. People can have temperature sensation reversal with hot things feeling cold and cold things hot.

Other Ciguatera warning signs
In March, the Commonwealth Healthcare Corporation (CHCC) in Saipan, part of the Northern Mariana Islands, reported it was seeing an increase in Ciguatera poisoning because of the consumption of various fish.

A study published in the journal Clinical Toxicology in 2020 looked at Ciguatera fish poisoning cases handled by the French Poison Control Centre Network from 2012 through 2019.

Fifty-two events were studied involving 130 patients. The fish species was identified on 41 occasions and mainly belonged to five fish families including groupers, snappers, jacks, parrotfish and barracudas. Origin of the fish was mainly the Atlantic Ocean followed by the Indian and Pacific Ocean.

Numerous patients reported exacerbation of neurological signs several months after poisoning following consumption of alcohol or seafood.

Meanwhile, researchers at the Institute of Natural Products and Agrobiology (IPNA-CSIC) are working on a Ciguatera vaccine. Scientists have managed to obtain the first molecule in development of the vaccine that would be used as a treatment, rather than for prevention.