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Campylobacter Jejuni Outbreak in Denmark
3 months ago •source ssi.dk
Denmark
Update September 29th, 2025:The Statens Serum Institut (SSI) has confirmed that the two ongoing Campylobacter jejuni outbreaks in Denmark, linked to sequence types (ST) 49 and 52, are caused by Danish chicken. As of September 17, 2025, the outbreaks have affected 55 and 26 patients, respectively, across the country. Patients range from 2–90 years old, and about half required hospitalization.
Because only about 10% of Campylobacter cases undergo sequence-based surveillance, officials believe the true number of illnesses linked to these outbreaks likely involves several hundred people. Both outbreak strains (ST49 and ST52) have been associated with previous disease outbreaks in Denmark.
The Central Outbreak Group, which includes SSI, the Danish Veterinary and Food Administration, and the National Food Institute, continues to investigate. Whole-genome sequencing has shown close genetic similarity among patient samples, supporting the link to Danish chicken as the infection source.
Source: Statens Serum Institut (SSI)
September 23rd, 2025:
Since July 2025, Denmark has been experiencing an increase in Campylobacter jejuni cases, with two specific outbreaks involving sequence types 49 and 52. The Statens Serum Institut (SSI) has reported 32 individuals affected across the country, with half requiring hospitalization. The outbreaks are part of a broader rise in Campylobacter infections nationwide in Denmark.
Between July 14 and September 8, 2025, the SSI registered two outbreaks of Campylobacter jejuni, affecting 20 and 12 people, respectively. The patients, ranging from 2 to 89 years old, are distributed across various regions in Denmark. The outbreaks have been linked to sequence types 49 and 52, which have previously caused similar incidents in the country. Due to limited subtyping, the actual number of cases is likely underestimated, potentially involving several hundred individuals.
The Central Outbreak Group, comprising SSI, the Danish Veterinary and Food Administration, and the National Food Institute of Denmark, is investigating the outbreaks. Whole-genome sequencing of patient samples is being conducted by SSI, while the Danish Veterinary and Food Administration examines product and environmental samples. The comparison of human and product samples aims to identify the source of the outbreaks.
Source: www.ssi.dk/aktuelt/nyheder/2025/to-udbrud-med-campylobacter-skyldes-dansk-kylling
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