Listeria infections remained steady and seven outbreaks were investigated by the UK Health Security Agency (UKHSA) in 2024.

There were 179 cases of listeriosis reported in England and Wales in 2024, compared to 177 in 2023.

The latest data show that while Listeria can infect people of all ages, it poses a greater risk to vulnerable groups, with the most cases in people aged 80 and older. Of the 28 deaths among 142 non-pregnancy cases, 12 were 80 years old and older.

Overall, the incidence of listeriosis was lower in males than females with 79 males and 100 females infected. It was higher in the age groups, 60 to 69, 70 to 79, and 80 years and older. Pregnancy associated infections accounted for 37 cases and some resulted in stillbirth or miscarriage.  

London had the highest incidence rate with 35 cases, whilst the East of England had the lowest. The North East had the fewest cases with seven. Ten infections were recorded in Wales. June and September were the peak months for listeriosis reporting in 2024.

Vanessa Wong, UKHSA consultant in gastrointestinal infections, said: “Listeriosis is a rare infection and most people only experience mild symptoms of gastroenteritis that usually pass within a few days without the need for treatment. However, severe listeriosis is more likely to affect the elderly, very young babies, pregnant women and those with a weakened immune system.

“The best way to prevent listeriosis is to practice good food hygiene and avoid high-risk foods if you are in a vulnerable group. Foods that carry a greater risk of Listeria include: soft cheeses, pâté, smoked fish, chilled sliced meats and other chilled ready-to-eat products.”

Outbreak investigations
UKHSA investigated seven outbreaks across England and Wales, linked to products including smoked fish, chocolate and strawberry mousse, garlic sausage and pre-packed sandwiches. The biggest outbreak had 19 cases from 2020 to 2024 and was traced to smoked fish. The source of an outbreak with nine cases from 2021 to 2024 remains unknown.

In the fish outbreak, which also affects Scotland, four people have died, two of which had Listeria monocytogenes listed as a cause of death, along with other underlying health conditions. In December 2022, Lidl recalled Deluxe Oak Smoked Scottish Louch Trout and Lighthouse Bay Smoked Trout Trimmings, produced by St. James Smokehouse in Scotland. Product testing found Listeria that matched the outbreak strain. All samples positive for the outbreak strain have been within the permitted limit of 100 colony forming units per gram (CFU/g).

Risk mitigation measures included updates to NHS guidance to include smoked fish as high risk for listeriosis amongst the vulnerable population as well as warning labels on certain smoked fish products to inform consumers they may pose a microbiological risk to vulnerable groups.

Five people were sickened in two outbreaks linked to prepacked sandwiches. Contaminated chocolate or strawberry mousse led to five people falling ill and garlic sausage was behind three infections.

In the mousse outbreak, patients were identified from May to December 2024. Two lived in Yorkshire and Humber and one each in the North West and West Midlands, plus one in Wales. The median age of cases was 87 and they ranged from 68 to 89 years old. Three people died, including one wher Listeria monocytogenes was reported as the cause of death.

The investigation found an association with Cool Delight Desserts supplied to the NHS. Listeria monocytogenes was detected twice in food and matched clinical isolates: a chocolate and vanilla mousse and a strawberry and vanilla mousse both sampled in February 2025 at an NHS hospital in the South West. Levels of Listeria were below the regulatory threshold of 100 CFU/g.