Authorities in the United Kingdom have repeated a warning about Listeria in fish as part of an outbreak involving three deaths.

The Food Standards Agency (FSA), Food Standards Scotland (FSS), and the UK Health Security Agency (UKHSA) said vulnerable consumers need to be aware of the risks of Listeria monocytogenes infection from ready-to-eat (RTE) smoked fish.

The number of people affected in the outbreak has gone up by two to 14 since it was announced in April this year. At least three patients live in Scotland and the first illness onset date of all cases was in October 2020.

Ten sick people are older than age 65, and one is a pregnant woman. Three of those affected who were older than 65 died.

Increase in infections this year
Of the 14 linked cases of listeriosis since 2020, eight have been identified since January 2022 in England and Scotland. The majority of them reported eating ready-to-eat smoked fish.

Caroline Handford, acting head of incidents at the FSA, said vulnerable people need to be aware of the ongoing risks of consuming ready-to-eat smoked fish.

“If anyone from these groups is eating ready-to-eat smoked fish, we are reminding them of the advice to ensure that it is thoroughly cooked before they eat it including when served as part of a dish. People can also further reduce the risk by keeping chilled ready-to-eat smoked fish cold at 5 degrees C (41 degrees F) or below, always using products by their use-by date, following the storage instructions on the label, and cooking it until it is piping hot right through,” she said.

Advice to people over the age of 65, those who are pregnant or have weakened immune systems is that they should thoroughly cook ready-to-eat smoked fish before eating it. The warning covers chilled smoked fish products that would not normally be cooked at home before being eaten.

“Some people are at higher risk of much more serious illness, including those over 65, people who are pregnant or newborn babies, and those with weakened immune systems including people undergoing immunosuppressive treatment, and people with chronic liver or kidney disease,” said Saheer Gharbia, interim deputy director gastrointestinal infections and food safety at UKHSA.

“In light of this ongoing outbreak, we are advising pregnant and vulnerable people to only eat ready-to-eat smoked fish that has been thoroughly cooked to reduce the risk of listeriosis.”

About Listeria infections
Food contaminated with Listeria monocytogenes may not look or smell spoiled but can still cause serious and sometimes life-threatening infections. Anyone who has developed symptoms of Listeria infection should seek medical treatment and tell their doctors about possible Listeria exposure.

Also, after eating suspect food, people should monitor themselves for food poisoning symptoms during the coming weeks because it can take up to 70 days after exposure to Listeria for symptoms of listeriosis to develop.

Symptoms of Listeria infection can include vomiting, nausea, persistent fever, muscle aches, severe headache, and neck stiffness. Specific laboratory tests are required to diagnose Listeria infections, which can mimic other illnesses.

Pregnant women, the elderly, young children, and people such as cancer patients who have weakened immune systems are particularly at risk of serious illnesses, life-threatening infections, and other complications. Although infected pregnant women may experience only mild, flu-like symptoms, their infections can lead to premature delivery, infection of the newborn, or even stillbirth.

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