Epidemiological update: Multi-national outbreak of S. Enteritidis infections among junior ice hockey players – Riga Cup 2015

Epidemiological update

​On 16 April, Finland reported an outbreak of salmonellosis among junior ice-hockey players at the Riga Cup.

​On 16 April, Finland reported an outbreak of salmonellosis among junior ice-hockey players at the Riga Cup through the Early Warning and Response System (EWRS) and the Epidemic intelligence Information System for Food and Waterborne Diseases (EPIS-FWD). Following the alert, Latvian public health authorities contacted the team leaders in all countries to find-out if cases had been reported in other teams.

Around 5 000 players from Austria, Belarus, Czech Republic, Denmark, Estonia, Finland, Germany, Hungary, Latvia, Lithuania, Luxemburg, Norway, Poland, Russian Federation, Slovakia, Sweden, Switzerland, the United Kingdom and Ukraine participated in the Cup from 27 March to 26 April. The games were played in four arenas. A fifth arena was added for the last Riga Cup weekend (24-26 April).

As of 22 May, 42 teams have reported 187 cases from six different countries (Estonia, Finland, Lithuania, Norway, Sweden and the United Kingdom). Microbiological typing revealed S. Enteritidis Phage type 1 with a rare MLVA profile 3-10-6-4-1 as the causative agent.

Through the Finnish Infectious Disease Registry, 75 salmonellosis cases from 16 teams were notified. Date of notification ranged between 1 April and 6 May. Five boys have been hospitalised due to their illness. Based on the inquiry among 50 Finnish teams, 92 cases have been identified from 23 teams.

Sweden have identified 15 cases via the Swedish notification system. The latest date of onset was on 26 April 2015. Through the questionnaire sent to team leaders, 57 cases from ten teams were identified. In addition, Estonia reported five cases (one team affected), Lithuania reported four cases (two teams affected), Norway reported 14 cases (three affected teams) and the United Kingdom reported 15 cases (three teams affected). No cases were identified among the Latvian team members.

Retrospective cohort studies were initiated by national public health authorities among Finnish, Swedish, Latvian and United Kingdom teams participating in the tournament on 17–19 April. The teams with cases stayed at four different hotels in Latvia but all ate organised meals in the arenas. Countries participating in the retrospective cohort studies are currently pulling together information about their cases in order to identify a common exposure. 

Finland, Norway and Sweden performed MLVA typing on 17 isolates and all identified the same rare MLVA profile.

On 16 April and 27 April, the Latvian Public Health authority interviewed the staff at the venues cafeteria where the tournament was taking place and took environmental swab and faecal samples that yielded negative results.

ECDC threat assessment for the EU
Considering that all cases reported were participating to the junior hockey cup in Riga (cases clustered in time and place), and that the results of the microbiological typing confirmed a link between the cases, this outbreak can be considered a point source outbreak with a common exposure.
The Riga Cup tournament has ended but other tournaments are continuing in the same venue until the end of May. Despite the source(s) of infection still not identified, no new cases were reported in the past two weeks which could indicate that the measures implemented in the venues cafeterias in Riga might have been successful.
ECDC encourages all Member States to report through EPIS-FWD any case possibly associated to an event occurring in the Riga until the end of May.