Since 1 January 2013, 15 laboratory-confirmed cases of HAV infection have been reported in Germany, the Netherlands and Poland. All cases have a travel history to the autonomous provinces of Trento and Bolzano in northern Italy during the exposure period. During the same period, Italy experienced an increase in cases of HAV infection, both in province of Trento and at national level. In the first six months of 2013, Italy reported more than 200 cases in excess to the mean number of cases reported in the same time period of the last three years and likely to be associated with this outbreak. Finally, three Irish cases whose isolates share identical sequence to the Italian outbreak and without any history of travel to Italy, nor contact with other HAV cases, had onset of illness in April 2013 in Ireland. As the exposure of the cases occurred in Italy and Ireland, this suggests that cases have been exposed to the same contaminated vehicle of infection distributed at least to these two countries. Epidemiological, microbiological and environmental investigations indicate mixed frozen berries as the most likely vehicle of infection for these outbreaks. A national case control study is under way in Italy. In addition, sequencing analyses of isolates from human and food samples and environmental and food trace-back investigations are on-going in Italy and Ireland. The results of these investigations are expected to bring more evidence on the implicated vehicle of infection and on the pathway of its contamination. Despite the withdrawal of the incriminated food product, it is likely that additional cases will be identified and reported in Italy and, possibly, in Ireland, because of the long shelf-life of such frozen products. ECDC invites Member States to raise awareness of a possible increase in HAV cases associated with the Italian outbreak strain, to report all new cases in EPIS-FWD, to use the common epidemic case definition and questionnaire to interview recent cases and to sequence a subset of viral specimens in order to disclose possible links with the current outbreak in Italy. For additional sequence information or comparison, or assistance in sequencing if no facilities are available locally, the HAVNET can be contacted directly (havnet [at] rivm.nl). Member States, in accordance with their national guidelines, may consider active or passive immunisation of close contacts to cases in order to avoid secondary transmission. ECDC, EFSA and the European Commission, in cooperation with the affected Member States, will continue to closely monitor this event and will update the risk assessment as soon as new relevant information becomes available. Two other HAV-related outbreaks are simultaneously under investigation in four Nordic countries and in travellers returning from Egypt. A third food borne HAV-related outbreak is under investigation in the USA. At present, there is no evidence of common links between these outbreaks.
First published in EFSA Supporting Publications:
10 July 2013
10 July 2013