Researchers from the European Centre for Disease Prevention and Control and Maastricht University Medical Centre have published a report into three multi-country foodborne outbreaks of hepatitis A virus (HAV) infection reported in 2013 and their implications for the EU.
The three outbreaks concerned were reported between March and May 2013 and affected more than 400 people in 16 European countries. The first outbreak was confined to Scandinavia and was associated with consumption of strawberries imported from Egypt and Morocco. The second affected people in 14 countries who had travelled to Egypt. Foodborne transmission was suspected and strawberries were again identified as a possible vehicle.
The third and largest outbreak was centred on Italy and affected travellers from other countries, but the outbreak strain of HAV was also found in people in Ireland with no travel history. Investigation of this outbreak found a link with frozen mixed berries – mostly imported from Eastern Europe. The outbreak strain of HAV was isolated from one food sample.
The authors of the report observe that the occurrence of three large foodborne outbreaks at the same time is very unusual, but conclude that there was no direct link between them. The outbreak strain of HAV in the Italian outbreak was a different subgenotype (1A) to that responsible for the other outbreaks (1B), while the 1B outbreak strains also differed significantly, although they are likely to have a common geographical origin.
The report includes recommendations for more research into the risks presented by frozen berries and for better surveillance and laboratory testing capacity to help prevent further large outbreaks of this type. Travellers to countries where HAV is endemic are also advised to consider vaccination.
The report is published in full in the online journal Eurosurveillance and can be found here.