New peak in multi-country Salmonella outbreak from eggs

Seven countries have reported more than 100 Salmonella cases linked to eggs from Poland pushing the total number of infections past 600.

Belgium, France, Luxembourg, the Netherlands, Norway, Sweden and the UK have 96 confirmed and 34 probable new cases associated with the outbreak of S. Enteritidis.

From May 2016 to June 2017, 14 countries had 280 confirmed and 257 probable cases.

From 2012 to March 2016, 107 historical confirmed and 24 probable cases were also reported.

A five-year-old child died in Croatia and Hungary also reported a fatal case.

Temporary fall due to control measures

A 2016 outbreak investigation identified eggs from three Polish packing centres as the vehicle of infection.

Fermy Drobiu Woźniak (Wozniak Poultry Farms) was named as the supplier by several national authorities. However, the firm told us testing by an accredited lab did not show Salmonella in eggs.

Following control measures at the farm and distribution level in November last year new cases fell.

However, since March 2017 the number of new cases has increased again with a peak of 38 cases in May and a second peak of 46 infections in September.

Due to reporting delays, additional cases are expected with onset in recent months, said the European Centre for Disease Prevention and Control (ECDC).

ECDC said outbreak-confirmed cases belong to two different WGS clusters: Cluster_175 and Cluster_360.

These two WGS clusters were also detected during the 2016 environmental and veterinary investigations at the sites producing the tainted eggs.

While most human isolates belonged to Cluster_175 between January and June 2017, isolates belonging to the Cluster_360 have been more frequently seen since July 2017.

Most cases in UK; Bulgaria now affected

Most of the 200 cases (155 confirmed and 45 probable) identified with onset from January to September this year were reported by the UK (135 confirmed and three probable). However, the UK is the only country performing routine WGS-based typing of Salmonella.

So the number of cases from other EU/EEA countries is most likely underestimated, added ECDC.

Of the 35 cases probably infected outside their country of residence since July 2017, 24 had a travel history to Bulgaria (six confirmed and six probable) or to Greece (two confirmed and ten probable).

ECDC said the single case with a travel history to Bulgaria noted before July 2017 had onset in June so it is plausible that the country has only been recently affected by the outbreak.

Six EU Member States (Belgium, France, Italy, Norway, Sweden and the UK) noted 50 confirmed and 12 probable cases in an update earlier this year.

ECDC is offering sequencing services for countries reporting probable cases of human S. Enteritidis isolates with MLVA profile 2-9-7-3-2 or 2-9-6-3-2.