Tracing of food items in connection to the multinational hepatitis A virus outbreak in Europe
In May 2013, Germany reported cases of hepatitis A virus (HAV) genotype IA infection in persons with a travel history and Italy reported a national increase in the number of HAV cases and declared an outbreak. Confirmed cases (outbreak strain KF182323) have been reported in Denmark, Finland, France, Germany, Ireland, Norway, the Netherlands, Poland, Sweden and the United Kingdom (331 in total). HAV contamination was detected in frozen mixed berries (14 lots) and mixed berry cakes/pastries (2 lots) in Italy, France and Norway. In Ireland, the Netherlands and Sweden, analysis of food histories and questionnaires identified suspect berries and berry products consumed by confirmed cases. Tracing began with 38 lots/cases from Italy, Ireland and the Netherlands, an additional 5 lots/cases were added from France, Norway and Sweden in spring 2014. The tracing data were exchanged via the European Rapid Alert System for Food and Feed. The final dataset comprises 6227 transactions among 1974 food operators. Bulgarian blackberries and Polish redcurrants were the most common ingredients in the traced lots/cases; however, Poland is the largest producer of redcurrants in Europe, and Bulgaria is a major exporter of frozen blackberries. No single point source of contamination linking all 43 lots/cases could be identified. HAV cases/lots in five countries could be linked to seven Polish freezing processors and/or to five frozen berry suppliers in Bulgaria. This indicates that HAV contamination could be occurring at the freezing processor or in primary production of berries and therefore compliance with Good Hygiene Practice, Good Manufacturing Practice and Good Agricultural Practice is recommended for countries producing berries for freezing. It is possible that contaminated product related to this outbreak could still be circulating in the food chain. Hence, for the public health domain, enhanced surveillance, risk communication, vaccination and further research are recommended.