Rapid Outbreak Assessment: Update: Outbreak of hepatitis A virus infection in Italy and Ireland

Risk assessment

​Since publishing the ’Joint ECDC-EFSA rapid outbreak assessment: Outbreak of hepatitis A virus infection in residents and travellers to Italy’ in May, new information has emerged as a result of the epidemiological, microbiological and environmental investigations. Therefore, ECDC has updated its previous assessment.

Executive summary

The ongoing outbreak of Hepatitis A virus (HAV) infection that has affected travellers to Italy from Germany, the Netherlands and Poland, as well as local residents in Italy, may now be affecting Ireland. 
Three cases of HAV have been reported in Ireland, although none of the three has any travel history to Italy. Nor have they had any contact with other HAV cases. Isolates of the virus from the three Irish cases reveal an identical sequence to that found in the Italian outbreak.
Onset of illness in the Irish cases was April 2013. Additional case finding activity is currently underway. Exposure of cases in both Italy and Ireland suggests that the same contaminated vehicle of infection has been available in at least these two countries. In Italy, mixed frozen berries have been indicated as the most likely vehicle of infection by epidemiological, microbiological and environmental investigations. In late May, an Italian distributor withdrew mixed frozen berries from the market following identification of a package contaminated with virus identical to the outbreak strain.
The most recent cases in the ongoing HAV infection outbreak have been reported by Italy. The onset of symptoms in these cases was recorded in June 2013. Due to the long shelf life of frozen berries and to the average length of approximately one month for incubation of HAV, more cases are expected to be reported.

While there is evidence pointing towards mixed frozen berries as the vehicle of infection, the specific berry type has not yet been identified. The point of contamination remains unknown at this time and as a result it is not yet possible to exclude the occurrence of associated cases in other EU Member States.