Meat is the suspected vehicle of infection, according to the European Food Safety Authority (EFSA) and European Centers for Disease Control and Prevention (ECDC).
A total of 38 people have been affected from Denmark (16), Finland (9), Germany (6) Sweden (5), Norway (1) and the Netherlands (1) with more illnesses expected.
The MLVA profiles 3-12-17-NA-211 and 3-12-18-NA-211 had not been reported in any of the affected EU/EEA countries before 2014.
ECDC recommends that Salmonella Typhimurium isolates be typed using the standard Multiple Locus Variable number tandem repeat Analysis (MLVA) protocol.
More cases expected
Since isolates from August have not yet been typed in most countries more cases may be identified.
A monophasic S. Typhimurium cluster with MLVA profile, 3-12-17-NA-211, was detected through the European Surveillance System (TESSy) on 4 August.
On 18 August, a second cluster with a closely-related MLVA profile, 3-12-18-NA-211 was detected.
The three countries involved, Denmark, Norway and Sweden, had not identified human cases presenting with these MLVA profiles in the past.
Member State appeal
On August 22, ECDC launched an urgent inquiry to see whether other Member States had identified cases with these MLVA patterns. Finland, Germany and the Netherlands, confirmed having identified cases with the two MLVA profiles for the first time ever in 2014.
18 cases with the MLVA type 3-12-17-NA-211 and four cases with the type 3-12-18-NA-211 have been reported as of August 29.
They were received at the reference laboratories in Denmark, Sweden and Norway between 23 June and 25 July.
Fourteen are male and eight female, with ages ranging from three to 77 years (median 43).
An additional 20 cases have been reported by Germany, Finland and the Netherlands through the Epidemic Intelligence Information System for Food- and Waterborne Diseases (EPIS-FWD).
Since not all countries are using MLVA typing, it is possible that cases are also occurring in other countries but that their links to this cluster remain undetected, said ECDC.
Monophasic Salmonella Typhimurium was the third most frequently reported serotype in the EU/EEA countries, with 5,932 cases in TESSy in 2012.