Greece, Germany, Czech Republic and Luxembourg have reported 40 cases of the Salmonella serotype with an antigenic formula 11:z41:enz15, which has never been described before.
The Salmonella serotype was found in imported sesame seeds in Germany from Nigeria.
ECDC said as sesame seeds have a long shelf life and cases have been reported recently, it is likely contaminated batches have been in the food chain for several months in a number of Member States.
Link to sesame-based products
Greece has reported 22 cases since March 2016, including 15 children less than 15 years of age. Two cases have been detected in 2017, the most recent at the end of February.
In Greece, a study of 11 cases with the new serotype and 22 cases of Salmonella Enteritidis indicated an association between disease and consumption of tahini (a sesame-based product).
Cases reported eating commercial products but no specific trademark was implicated.
In the Czech Republic, two of five cases mentioned possible consumption of sesame-based products.
Germany has 10 cases since May 2016 and the last one was notified in February this year.
Four cases had an epidemiological link to Greece, either through travel or a case visited by Greek relatives. The other six cases were exposed in Germany.
The Salmonella serotype was detected during a company’s check of sesame seeds in October 2016.
WGS analysis concluded the Salmonella food isolate was identical to the human isolates.
Germany issued an RASFF notification on 22 February 2017.
Czech Republic has five cases (two males and three females), three of which are children. The most recent case was notified at the end of June 2016. None of the cases were travel-related.
Luxembourg has reported one symptomatic and two asymptomatic cases, with the latest notification in February 2017.
Twelve countries (Austria, Cyprus, Denmark, Finland, France, Ireland, Italy, the Netherlands, Norway, Scotland, Sweden and Switzerland) did not have any of the novel human Salmonella isolates.
Initial discovery
The Salmonella isolates with the unusual antigenic type were identified by the National Reference Laboratory for Salmonella and Shigella (NRLSS) in Greece.
The pulsed-field gel electrophoresis (PFGE) profile was uploaded to the European Surveillance System (TESSy).
By the end of 2016, the Greek National Reference Centre had around 200 Salmonella isolates waiting to be serotyped; so additional cases during that period could emerge later.
The Pasteur Institute in Paris confirmed results of a Greek laboratory, verifying a new serotype of Salmonella enterica subspecies enterica.
If this is confirmed by additional testing, a name will be given to the new serotype.