Yersinia outbreak linked to imported iceberg lettuce

An outbreak of Yersinia in Sweden has ended with iceberg lettuce because the suspected supply of an infection.

From January till the start of February this 12 months, twice as many individuals fell unwell with Yersinia an infection as did throughout the identical interval in a traditional 12 months.

From 53 instances of Yersinia enterocolitica, 33 lived in Stockholm, Västra Götaland and Halland. Isolates from 24 of those instances had been typed by complete genome sequencing and 16 outbreak sufferers with clustered isolates of sequence kind 18 could possibly be recognized.

Of those 16, eleven had been girls and 5 had been males aged 7 to 34 years outdated. All fell unwell between Jan. 4 and 18.

Managing sources
Rikard Dryselius, a microbiologist at Folkhälsomyndigheten (Public Well being Company of Sweden), mentioned assortment and typing of Yersinia isolates will not be performed routinely within the nation.

“As a substitute, particular person counties can ask for assist with typing Yersinia once they see a necessity. Alternatively, we could ask the laboratories to ship in isolates if we see a rise in instances nationally that must be investigated,” he mentioned.

“Because of the strained state of affairs for an infection management items and medical laboratories through the pandemic, we selected to request interviews/questionnaire responses and assortment of isolates solely from the counties the place the rise was highest. It’s due to this fact very probably that there have been greater than 16 outbreak instances however the lack of extra isolates to sequence implies that we can not affirm this.”

Folkhälsomyndigheten, an infection management items within the Stockholm, Västra Götaland and Halland areas and Livsmedelsverket (Swedish Meals Company) investigated the incident.

Well being officers interviewed sick folks and compiled questionnaire responses about what and the place they ate earlier than sickness onset.

A case-case research the place questionnaire responses from outbreak instances had been in contrast with solutions from folks with Yersinia an infection that didn’t belong to the outbreak was performed.

Restaurant and iceberg lettuce hyperlink
The investigators discovered the outbreak instances had, to a larger extent, visited a sure restaurant chain. Observe-up interviews about what they’d eaten led to iceberg lettuce being suspected because the supply of an infection.

In accordance with the trawling questionnaire despatched to outbreak instances, seven out of 12 talked about they’d visited the restaurant chain earlier than falling unwell whereas seven out of 72 instances with yersiniosis who responded to the identical questionnaire in 2019 talked about that they’d performed so.

The suspicion of a contaminated batch of iceberg lettuce distributed to a restaurant chain was strengthened by the outbreak timeline, which advised {that a} product with a large geographical unfold and a restricted shelf life was the underlying trigger.

Sweden has no vital manufacturing of iceberg lettuce presently of 12 months and makes an attempt are being made to hint the nation of origin.

In the meantime, investigations are ongoing to seek out the supply of a Salmonella Enteritidis outbreak within the nation. It’s not associated to the Salmonella outbreak in Norway linked to meat from Germany.

The primary individual fell unwell on the finish of December 2020. There are 25 confirmed sufferers throughout 14 areas in southern and central Sweden.

Virtually three quarters of sufferers are kids youthful than 10 years of age and 4 are older than 70.

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