Foodborne outbreaks declined in Norway in 2024, but the number of people sick in them increased, mainly because of one of the largest Salmonella outbreaks in decades.

More outbreaks led to the number of Salmonella patients being the highest for more than a decade in 2024. Salmonellosis increased from 756 infections in 2023 to 1,197 in 2024. More than half of these reported that they were infected in Norway.

Data comes from a report published by the Norwegian Institute of Public Health (FHI). In 2023, there were 25 outbreaks with 518 people sickened.

Major Salmonella outbreak
“Overall, the report shows that the incidence of diseases transmitted from food, water, and animals is at the same level as in previous years. However, we have seen an increase in Salmonella infections in recent years. This is because we are back to the level we had before the pandemic and several national outbreaks in 2024,” said Siri Feruglio, from FHI.

“The increase is primarily due to several Salmonella outbreaks, including the largest outbreak we have had in Norway since the 1980s, with over 230 infected people. The source of infection was alfalfa sprouts produced from imported seeds.”

For Salmonella cases with a known place of infection, 575 were infected in Norway and 480 were infected abroad. The top countries of infection were Turkey, Thailand, and Spain.

Of all reported cases, 420 were hospitalized. The most patients were in the age group 50 to 59. Salmonella Enteritidis was the top cause of illness, followed by Salmonella Typhimurium and Salmonella Newport.

FHI received 22 reports of suspected or confirmed foodborne outbreaks with 889 people sick. Seven were caused by norovirus with 397 patients and six by Salmonella with 361 patients. imported tahini was the source of a Salmonella Muenster outbreak with 77 sick, of which 19 were /confirm/ied. Sweden also reported cases linked to the outbreak and detected Salmonella Muenster in tahini.

The number of patients in each outbreak varied from four to 238 people. Bacillus cereus, Cryptosporidium, and histamine all caused one outbreak each and for six the agent was unknown.

The largest outbreak also involved other countries and was caused by alfalfa sprouts produced from imported seeds. In Norway, there were 107 Salmonella Newport cases, 126 from Salmonella Typhimurium, three from Salmonella Kisarawe, and two from Salmonella Kinondoni. Salmonella Typhimurium and Salmonella Hvittingfoss outbreaks were also linked to alfalfa sprouts produced from seeds from the same Italian supplier.

Status of other main pathogens
A total of 3,091 cases of campylobacteriosis were reported compared to 3,033 in 2023. In 2024, the predominant type was Campylobacter jejuni with more than 1,097 patients. Almost 900 people were hospitalized. Among patients with a known site of infection, 1,126 were infected in Norway and 1,275 were infected abroad.

For those infected abroad, people had mainly been to Spain, Turkey, and Thailand. There were no Campylobacter outbreaks in 2024.

In 2024, 656 E. coli infections were reported compared to 662 in 2023. Among people with a known place of infection, 348 were infected in Norway and 140 were infected abroad.

The most cases were in the age group up to 9 years old. Serogroups O26 and O157 were the most common among reported cases.

EHEC infection led to hospitalization for 181 patients, with 33 in the age group 70 to 79. Among the 656 reported cases, three people developed hemolytic uremic syndrome (HUS). All HUS cases were children aged up to 9. Two of them were infected with O26 and one with O71. All HUS cases were infected in Norway. No outbreaks were recorded in 2024.

Thirty cases of listeriosis were reported compared to 39 in 2023. Among cases with a known place of infection, 24 were infected in Norway and four were infected abroad. All reported patients were hospitalized and the majority were in the age group 70 to 79 years old. There were no reported outbreaks in 2024.

There were also 599 Cryptosporidium infections, 72 Hepatitis A cases, and 89 Yersinia patients in 2024.