1 week Ago By Joe Whitworth
Sweden has published data on the number of people that were affected by major pathogens such as Salmonella, Campylobacter, E. coli, and Listeria in 2024. Data from Folkhälsomyndigheten (the Public Health Agency of Sweden) shows that outbreaks of Salmonella led to the highest incidence of cases infected in Sweden since 2010.
Whole genome sequencing identified six major outbreaks with 10 or more patients. In 2024, the number of infections increased by more than 20 percent to 1,612 and the incidence of domestic cases was the highest for 14 years. Among those infected abroad, people had mainly been to Thailand, followed by Turkey, and Spain.
A contributing factor was two large outbreaks linked to Ukrainian eggs and alfalfa sprouts produced from seeds from Italy, with more than 100 patients in each outbreak. The outbreak with sprouts covered several countries and the investigation continued in 2025. For all patients, the median age was 42 with a range of younger than 1 year old to 99 but gender distribution was even.
Among people infected in Sweden, the incidence was highest among children 0 to 4 years of age, followed by adults more than 70 years old. Serotypes were determined for isolates from 902 patients. Of the serotyped isolates from 803 patients infected in Sweden, 81 serotypes were identified, the most common of which were Salmonella Enteritidis and Salmonella Typhimurium.
Of the 89 isolates from patients infected abroad, Salmonella Enteritidis was, as in previous years, the most common. Campylobacter and E. coli picture For Campylobacter, E.
coli and Cryptosporidium, a decrease was seen compared to 2023. The number of cases of Campylobacter infection was relatively stable during 2022 to 2024 and significantly lower than from 2014 to 2018, which were impacted by several outbreaks. Over a longer period of time, E.
coli has increased, which is partly because of improved diagnostics. A total of 5,440 Campylobacter infections were reported, a decrease compared to 5,675 in 2023. The incidence of cases infected in Sweden was the same as the previous year, while the proportion of people infected abroad decreased.
For cases infected outside Sweden, it was most common to have been to Spain or Thailand. Incidence was highest in the age groups 60 to 69 and 50 to 59 and was higher among men than women in most age groups. Most cases occurred in July to August.
The increase in summer was preceded by a rise in the proportion of positive findings of Campylobacter in broiler flocks. In 2024, 848 cases of E. coli were reported.
This is a decrease from 939 cases in 2023. For people who got sick abroad, people were mainly infected in Turkey or Egypt. Slightly more women than men were infected, which is in line with previous years.
The incidence was highest among children aged 1 to 4 years old. A total of 17 cases of the serious complication hemolytic uremic syndrome (HUS) were reported. Eleven were infected in Sweden and 10 were children under the age of 10.
Seven serotypes were identified, O26:H11 four times and O157:H7 on three occasions. A total of 411 E. coli isolates were typed with whole genome sequencing in 2024.
Among these, 87 different serotypes were identified. The most common types were, as in previous years, O157:H7, O26:H11, and O103:H2. Listeria and other results For hepatitis A, Listeria, Shigella, and Yersinia, there were only minor differences in the number of cases compared to 2023.
A total of 114 Listeria infections were reported, down from 131 in 2023, and 23 people died within 30 days of the date of sampling. The median age was 77 with a range of 17 to 99 years old and 69 cases were women. As in previous years, the incidence was highest in people older than 80.
Based on typing data, 50 isolates were identified as belonging to 27 different clusters, of which 23 clusters also contained Listeria isolates identified before 2024. Swedish officials said the large number of clusters indicates ongoing and long-term spread of infection from unknown sources. Two small clusters were linked to locally produced cured meat products.
Pickles were the suspected source of one cluster with three cases. (To sign up for a free subscription to Food Safety News, click here .).
