Danish public health officials have reported two Salmonella outbreaks with 48 people sick.
Since the beginning of November, the Statens Serum Institut (SSI) has registered 18 cases of Salmonella Strathcona. Patients are 13 women and five men. They are between 5 and 85 years old, with a median age of 51. Patients have been reported across the country with eight in Syddanmark, five in Midtjylland, three in Nordjylland, and two in Sjælland.
The outbreak is being investigated by SSI, the Danish Veterinary and Food Administration (Fødevarestyrelsen) and the National Food Institute.
EU-wide implications
SSI is responsible for whole genome sequencing (WGS) isolates from sick people and conducting patient interviews to try and identify the source of infection. WGS of the bacteria from patients shows they are very closely genetically related, and all belong to sequence type 2559.
This strain of Salmonella Strathcona has been detected in the EU for more than a decade, with the first outbreak in Denmark in 2011 linked to tomatoes from Sicily.
In October, the European Centre for Disease Prevention and Control (ECDC) said this outbreak has resulted in 437 cases in 20 countries between January 2023 and September 2025. Ten cases have been reported in Canada and 24 in the United States. Available travel information shows ill people had been to Europe before getting sick.
In January 2025, Salmonella Strathcona was detected in a sample of irrigation water collected at the site of a tomato producer in Sicily, confirming the role of the environment in contamination. Testing of tomatoes did not find the outbreak strain.
The involved Italian producer implemented corrective measures, including a monthly own check sampling of irrigation water and tomatoes for Salmonella and E. coli.
In April, authorities carried out official sampling to evaluate effectiveness of the measures. Salmonella was detected again in irrigation water. Use of the irrigation well was prohibited. In May, this isolate was confirmed to be Salmonella Strathcona matching the outbreak strain. This led to an extended ban on use of the well.
Salmonella Typhimurium
In the second outbreak, SSI has recorded 30 cases of Salmonella Typhimurium since early November. A source has not yet been identified.
An equal number of men and women are sick. Patients are between 7 and 84 years old with a median age of 27. They live throughout the country with 11 in Midtjylland, seven in Hovedstaden, five in Sjælland, four in Syddanmark, and three in Nordjylland.
WGS of bacteria isolated from the patients shows they are very closely genetically related and all belong to sequence type 19. This suggests a common source of infection.
SSI, the Danish Veterinary and Food Administration (Fødevarestyrelsen) and the National Food Institute are investigating the incident.
