E. coli infections hit a record high in Norway in 2023, while other pathogens are returning to levels seen before the Coronavirus pandemic.

Data published by the Norwegian Institute of Public Health (FHI) shows that the number of Campylobacter, Salmonella, E. coli, and Listeria infections rose compared to the previous year, while Yersinia cases fell.

A total of 3,034 cases of campylobacteriosis were reported. Half were infected in Norway, and half were infected abroad in cases wher a known place of infection was present. This information was not available for almost 600 cases. The most common travel destinations for sick people were Spain, including the Canary Islands and Mallorca, Turkey, and Thailand.

Campylobacter is behind in most cases, but the amount is still lower than before the pandemic. While for the majority, no detail was given on the type found, Campylobacter jejuni caused more than 1,100 cases. Men were slightly more affected than women, and 907 people were hospitalized.

A previous article covered details of 25 outbreaks in 2023 that were caused by contaminated foodstuffs, with 518 people sick.

Record E. coli high

For E. coli, there were 663 cases, with three-quarters infected in Norway and a quarter infected abroad. This data was not known for 158 sick people. The age group 0 to 9 was the most affected, followed by 20 to 29-year-olds and 50 to 59-year-olds.

The number of reported E. coli cases was the highest number ever seen. It is unclear if the rise is due to better diagnostics, more people being tested, or more people getting sick.

E. coli O26 and O157 were the top serogroups among reported cases. A total of 187 people were hospitalized, with 30 ranging in age from under 1 to 9 years old. Seventeen people developed hemolytic uremic syndrome (HUS), with 15 cases in the youngest age group. Nine belonged to the E. coli O26 outbreak, but others were infected with O26, O157, and O128ab.

For Salmonella, 757 cases were reported in 2023, with 37 percent infected in Norway and 63 percent infected abroad. This data was not known for more than 100 patients. The top travel-related infections were linked to Spain, including the Canary Islands and Mallorca, Turkey, and Thailand.

The majority of cases were reported in August, September, and October. Most were aged 20 to 29, 50 to 59, and 60 to 69. Almost 250 people needed hospital treatment. The cases were higher than 712 in 2022 but lower than before the pandemic, with 1,094 in 2019.

Salmonella Enteritidis was the top serovar with 240 cases, followed by Salmonella Typhimurium with 77.

Listeria and other pathogens

A total of 39 listeriosis cases were recorded, with the majority infected in Norway. Cases went up compared to 31 in 2022, which is the most since 2014. This trend is also seen elsewher in Europe, with an increasing elderly population vulnerable to infection, which is a potential explanation.

All patients were hospitalized, mainly in the age groups 70 to 79, 80 to 89, and 60 to 69. Sixteen were women and 23 were men.

539 cases of cryptosporidiosis were reported, with two-thirds infected in Norway and a third infected abroad. The number of travel-related cases was the highest ever recorded. Many patients were reported in August and September. Nearly 100 people were hospitalized. Most cases were in the age groups 30 to 39, 20 to 29, and 0 to 9.

Officials said there had been a steady increase in Cryptosporidium infections in recent years, down to better diagnostics, but probably also a real increase in cases.

In 2023, one case of brucellosis was infected abroad. There were 29 hepatitis A cases, of which 21 were hospitalized. Yersinia Enterocolitica caused 85 infections, and 30 people were hospitalized.