Swedish officials are investigating a national outbreak of Salmonella that has sickened 33 people.
Local counties, Livsmedelsverket (National Food Agency) and Folkhälsomyndigheten (Public Health Agency) are working together to investigate the illnesses and identify the source of infection.
The outbreak of Salmonella Enteritidis with multiple locus variable number of tandem repeat analysis (MLVA) type 2-10-7-3-2 was detected by Folkhälsomyndigheten’s monitoring program using Whole Genome Sequencing (WGS) in October.
The first illness onset date is Sept. 27, and the last one reported was Oct. 28 The investigation is ongoing. It is mainly adults who have fallen ill and they come from 14 counties in Sweden. The ages range from one to 76 years but no deaths have been reported.
A Folkhälsomyndigheten spokeswoman told Food Safety News that it suspects the illnesses have been caused by a food source distributed throughout the country.
“There has been a fall in reported cases since last week, but some single cases can be expected. We have no indications that this outbreak strain is causing an increase in other European countries,” she said.
Interviews with patients to find the source are being conducted by county medical officers.
A Livsmedelsverket spokesman said it has not issued any particular advice to consumers in relation to the outbreak.
“We might expect some new cases, but it seems that the number of incoming new cases has decreased lately. We have not performed any sampling of food, because there is no strong evidence indicating any particular food type,” he told Food Safety News.
Symptoms of Salmonella infection usually appear 12-72 hours after infection, and include fever, abdominal pain, diarrhea, nausea and sometimes vomiting. Illness usually lasts four to seven days, and most people recover without treatment.
Salmonella Enteritidis with MLVA type 2-10-7-3-2 has been detected four other times this year in Sweden besides the ongoing outbreak. It was found on 23 occasions last year with 10 cases linked to one outbreak.
This MLVA type does not match those isolates with MLVA profile 2-9-7-3-2; 2-9-6-3-2; 2-9-10-3-2; 2-10-6-3-2; 2-10-8-3-2; or 2-11-8-3-2 that are part of an Salmonella Enteritidis outbreak with more than 1,400 cases linked to eggs from Poland that has been ongoing since 2012 and has affected 18 countries.
The Folkhälsomyndigheten spokeswoman confirmed the outbreaks are not related.
“WGS has shown that this outbreak strain differs from the one related to the previous outbreak involving eggs, thereby indicating that the events are not connected.”
Sweden has reported 45 cases between 2012 and 2018 linked to the multi-country outbreak from eggs.
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