An outbreak of a rare type of salmonella has been declared in Sweden after more than 50 people fell ill. The outbreak of Salmonella Coeln is thought to have been caused by fresh sprouts.
From the end of August to October, 52 people from 14 regions with the same type of Salmonella Coeln were found thanks to whole genome sequencing. This means that it is likely that they have been infected by a common source.
Salmonellosis cases ranged in age from 0 to 85 years with a median of 35. A total of 27 women and 25 men were ill.
As there have been no new cases or samples of the outbreak strain from patients since October 26, public health officials believe the outbreak has ended.
Sprouts are suspected but not confirmed as the source
Local infection control units and municipalities assisted in the investigation with the National Food Administration and the Swedish Public Health Agency.
An earlier update, when the source had not been found, was given when 31 people were ill. The number of people affected by Salmonella Coeln in Sweden in 2020 and 2019 was single-digit.
The Swedish Public Health Agency conducted a case-by-case study based on questionnaires from regional infection control units that had Salmonella patients. These people answered questions about what they ate during the week before illness as part of the epidemiological investigation.
Responses from outbreak patients were compared with responses from salmonella cases that were not part of the outbreak. This found a link between disease with the outbreak strain and consumption of sprouts. A suspected link to sprouts had also been identified during investigations in a region.
It is believed that a suspected contaminated batch was delivered to grocery stores, wholesalers and commercial kitchens at the end of August.
Sampling and analysis of residual sprouts from sick people and from production did not find Salmonella, so suspicions that they were the source of infection could not be confirmed with microbiological analyzes.
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