Outbreak of Listeria in Sweden
Published: 2025-10-16
Listeriosis (listeria infection) is caused by the bacterium listeria monocytogenes, which occurs naturally in soil, water, and the intestines of many animals and sometimes humans. The infection is primarily transmitted through contaminated food—particularly those with long shelf lives or stored at refrigerator temperatures, such as smoked or cured fish, certain cheeses, ready-to-eat meals, and cold cuts. Human-to-human transmission is very rare, although a pregnant woman can pass the infection to her unborn child through the placenta.
Since late September 2025, multiple people have fallen ill after consuming a tasting menu at a restaurant in Stockholm. Local investigation is being led by Smittskydd Stockholm in collaboration with the Stockholm Environmental Administration, the Swedish Food Agency, and the Public Health Agency of Sweden (Folkhälsomyndigheten), which coordinates the national response and conducts genetic analyses.
A total of 15 confirmed cases of listeria have been identified, with the bacterium detected in the patients’ blood. Genetic sequencing of isolates from two cases shows they are identical, strongly indicating a common source of infection. None of the affected individuals have required intensive care. The cases are spread across 12 regions, with most in the Stockholm area. The latest information about this outbreak is available from Folkhälsomyndigheten.
All restaurant visitors from 23–27 September have been contacted and advised to seek medical attention if symptoms appear. Environmental and food samples from the restaurant have been collected and are under analysis. Genomic typing of the bacteria is ongoing to determine the source of the infection.
The Swedish Pathogens Portal continues to monitor and investigate research resources linked to emergent diseases, such as listeria. Information on such diseases, including on related data and other research resources, is added to our emerging pathogens section. Where possible, the portal will also create data dashboards, and other resources, to display data and accelerate research in the area.