England saw a 26 percent rise in Shiga toxin-producing Escherichia coli (STEC) infections from 2023 to 2024, according to the latest data from the UK Health Security Agency (UKHSA). The rise in cases may be attributable to one foodborne illness outbreak involving contaminated salad leaves, officials say.

Of the 2,544 laboratory confirmed STEC cases seen in England in 2024, 564 were STEC O157 and 1,980 were non-O157 serotypes. Hemolytic uremic syndrome (HUS) developed in 2.1 percent of STEC O157 patients and 1.7 percent of non-O157 patients. Among STEC O157 cases, two people died, and among non-O157 cases, five people died. The highest incidence of STEC cases in 2024 was in children between one and four years of age.

In 2024, UKHSA and partner agencies investigated five STEC outbreaks—all of which were non-O157—comprising 467 cases (348 in England specifically). The sources for three of the outbreaks were contaminated beef, fresh fruit, and salad leaves. The largest outbreak was linked to contaminated leafy greens which resulted in 293 cases (196 cases in England). Of the 293 cases, 126 people were hospitalized, 11 developed HUS, and two died.

STEC non-O157 cases in 2024 increased nearly three times since 2019, while O157 cases have returned to pre-COVID-19 pandemic levels. The increase in STEC non-O157 seen in 2024 is due to the outbreak linked to salad leaves. Additionally, more cases of illness are being detected due to the growing use of polymerase chain reaction (PCR) testing technology in laboratories.