Health official are investigating a possible link between smoked fish and a recent listeria outbreak. The UK Health Security Agency (UKHSA), Food Standards Agency, and Food Standards Scotland are investigating an outbreak of Listeria monocytogenes linked to smoked fish that sickened at least a dozen people in several countries.

According to a report from the Food Standards Agency, the cases have been identified in England and Scotland. The illnesses have occurred over a span of several months, dating back to 2020, with six of the cases reported since January 2022, and were confirmed via whole-genome sequencing analysis. One case was a person who was a pregnant woman. The “majority” of the individuals infected reported eating smoked fish. Amid the outbreak “advice for avoiding listeriosis infection is being updated to include smoked fish as a high-risk product.”

Caused by the bacterium Listeria monocytogenes, listeria a serious infection typically caused by consuming contaminated food. The bacterium typically affects young children, frail or elderly people, pregnant women, and others with weakened immune systems. It can cause high fever, severe headache, stiffness, nausea, abdominal pain, and diarrhea. In some cases, it can be fatal. Listeria infection can cause miscarriages and stillbirths among pregnant women.

“Listeria infection in most people is usually either unnoticed or may cause very mild gastrointestinal illness. However, it can have more serious consequences for some people, particularly those with pre-existing health conditions that cause weakened immunity, and people who are pregnant,” Professor Saheer Gharbia, Interim Deputy Director Gastrointestinal Infections and Food Safety (One Health) at UKHSA, said. “There are certain foods that are more risky, and in light of this outbreak, we are advising pregnant and vulnerable people to thoroughly cook smoked fish before eating it. If you have any concerns about your health please speak to your midwife, GP or hospital specialist team.”