Read the story here. Advertise at Before It's News here.
Profile image
By Food Safety News (Reporter)
Contributor profile | More stories
Story Views
Last hour:
Last 24 hours:

Yersinia outbreak linked to imported iceberg lettuce

% of readers think this story is Fact. Add your two cents.

An outbreak of Yersinia in Sweden has ended with iceberg lettuce as the suspected source of infection.

From January until the beginning of February this year, twice as many people fell ill with Yersinia infection as did during the same period in a normal year.

From 53 cases of Yersinia enterocolitica, 33 lived in Stockholm, Västra Götaland and Halland. Isolates from 24 of these cases were typed by whole genome sequencing and 16 outbreak patients with clustered isolates of sequence type 18 could be identified.

Of these 16, eleven were women and five were men aged 7 to 34 years old. All fell ill between Jan. 4 and 18.

Managing resources
Rikard Dryselius, a microbiologist at Folkhälsomyndigheten (Public Health Agency of Sweden), said collection and typing of Yersinia isolates is not done routinely in the country.

“Instead, individual counties can ask for help with typing Yersinia when they see a need. Alternatively, we may ask the laboratories to send in isolates if we see an increase in cases nationally that should be investigated,” he said.

“Due to the strained situation for infection control units and clinical laboratories during the pandemic, we chose to request interviews/questionnaire responses and collection of isolates only from the counties where the increase was highest. It is therefore very likely that there were more than 16 outbreak cases but the lack of additional isolates to sequence means that we cannot confirm this.”

Folkhälsomyndigheten, infection control units in the Stockholm, Västra Götaland and Halland regions and Livsmedelsverket (Swedish Food Agency) investigated the incident.

Health officials interviewed sick people and compiled questionnaire responses about what and where they ate before illness onset.

A case-case study where questionnaire responses from outbreak cases were compared with answers from people with Yersinia infection that did not belong to the outbreak was done.

Restaurant and iceberg lettuce link
The investigators found the outbreak cases had, to a greater extent, visited a certain restaurant chain. Follow-up interviews about what they had eaten led to iceberg lettuce being suspected as the source of infection.

According to the trawling questionnaire sent to outbreak cases, seven out of 12 mentioned they had visited the restaurant chain before falling ill while seven out of 72 cases with yersiniosis who responded to the same questionnaire in 2019 mentioned that they had done so.

The suspicion of a contaminated batch of iceberg lettuce distributed to a restaurant chain was strengthened by the outbreak timeline, which suggested that a product with a wide geographical spread and a limited shelf life was the underlying cause.

Sweden has no significant production of iceberg lettuce at this time of year and attempts are being made to trace the country of origin.

Meanwhile, investigations are ongoing to find the source of a Salmonella Enteritidis outbreak in the country. It is not related to the Salmonella outbreak in Norway linked to meat from Germany.

The first person fell ill at the end of December 2020. There are 25 confirmed patients across 14 regions in southern and central Sweden.

Almost three quarters of patients are children younger than 10 years of age and four are older than 70.

(To sign up for a free subscription to Food Safety News, click here.)


Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world.

Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.

"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.

Please Help Support BeforeitsNews by trying our Natural Health Products below!

Order by Phone at 888-809-8385 or online at M - F 9am to 5pm EST

Order by Phone at 888-388-7003 or online at M - F 9am to 5pm EST

Order by Phone at 888-388-7003 or online at M - F 9am to 5pm EST

Humic & Fulvic Trace Minerals Complex - Nature's most important supplement! Vivid Dreams again!

HNEX HydroNano EXtracellular Water - Improve immune system health and reduce inflammation

Ultimate Clinical Potency Curcumin - Natural pain relief, reduce inflammation and so much more.

MitoCopper - Bioavailable Copper destroys pathogens and gives you more energy. (See Blood Video)
Oxy Powder - Natural Colon Cleanser!  Cleans out toxic buildup with oxygen! 
Nascent Iodine - Promotes detoxification, mental focus and thyroid health.
Smart Meter Cover -  Reduces Smart Meter radiation by 96%!  (See Video)

Immusist Beverage Concentrate - Proprietary blend, formulated to reduce inflammation while hydrating and oxygenating the cells.

Report abuse


    Your Comments
    Question   Razz  Sad   Evil  Exclaim  Smile  Redface  Biggrin  Surprised  Eek   Confused   Cool  LOL   Mad   Twisted  Rolleyes   Wink  Idea  Arrow  Neutral  Cry   Mr. Green

    Load more ...




    Email this story
    Email this story

    If you really want to ban this commenter, please write down the reason:

    If you really want to disable all recommended stories, click on OK button. After that, you will be redirect to your options page.