Scientists have described the first confirmed ciguatera poisoning incident in the United Kingdom.

The suspected ciguatera incident occurred in England in June 2017 associated with the consumption of fish sold as red snapper steaks. Three people were affected from the same family after eating separate steaks from the same package.

Investigations revealed fish was harvested and processed in India and imported to the UK. The Food Standards Agency (FSA) was told about the incident, and a product withdrawal was done for the brand associated with intoxication. UK authorities concluded that fish from the same batch should not be released for retail sale.

Two of the three cases were admitted to hospital with symptoms of diarrhea and vomiting, followed by paresthesia and shortness of breath. They were kept under observation for two days. The other person was discharged before a follow-up hospital visit. Patients were 11, 20, and 45 years old.

Fish testing
The two older female patients presented similar complaints, including vomiting, diarrhea, muscle pain, shortness of breath and paresthesia, which included skin pain, itching, numbness, as well as pins and needles sensations. The third younger patient also experienced bone pain in the right shin, some reduced power in the legs, and diarrhea. All three patients had gastrointestinal symptoms with vomiting and/or diarrhea within six hours of consuming the fish. No long-term follow-up was carried out by the medical practitioners involved.

According to the study published in the journal Marine Drugs, it is estimated that 10,000 to 50,000 people are affected by ciguatera poisoning each year.

There are no regulatory limits or methods of analysis set within Europe or the United States. European Commission regulations require inspections to ensure fishery products do not contain biotoxins such as Ciguatoxins (CTX).

One remaining fish steak from the implicated batch was sent to the Centre for the Environment, Fisheries and Aquaculture science (Cefas) for assessment. It was analyzed for the presence of CTXs using multiple methods. Toxicity was determined in one of the implicated fish steaks.

Testing confirmed the presence of sodium channel specific activity consistent with a ciguatoxin standard. At the levels detected, human illness would be expected following fish consumption.

Mislabeled product
Three steaks from a pack of four were consumed, leaving one in frozen storage, which was submitted for DNA barcoding. This revealed the fish was Pinjalo snapper and not the marketed species of red snapper. 

Fish had been imported to the UK through a Midlands-based distributor. The original source was the Indian Ocean, with fish processed in a production and packaging facility in Alappuzha, Kerala, southern India prior to export. No information was made available about the origin of fish by the processors despite repeated requests.

Scientists said findings show the importance of continued surveillance of imports to the UK from high-risk regions, according to the researchers.

“We report here for the first time the confirmed intoxication in the UK from ciguatera poisoning as a result of toxic carnivorous reef fish being imported into the country and affecting the local population. We therefore highlight the importance of monitoring for the presence of these toxins, and the need to develop risk management strategies for protecting the human population from highly contaminated ciguateric fish,” they added.