Source of hepatitis A outbreak in Europe may be frozen berries

The number of cases of hepatitis A in 11 European countries has risen to 1315 since January 2013, show new figures from the European Food Safety Authority.

In a newly updated rapid outbreak assessment,1 the authority said that of the 1315 cases 240 were confirmed cases related to an ongoing outbreak of the infection.

The authority said its initial investigations indicated that the source of the infection was frozen berries, but other causes were possible, such as cross contamination in the food production environment. Experts said it was also possible that the strain had been widespread for a while but had previously been undetected.

Initially, the outbreak was associated with people who had travelled to Italy, but seven European countries—the United Kingdom, France, Germany, Ireland, Norway, the Netherlands, and Sweden—have reported cases of infections in people who had not travelled to Italy.

The authority is leading a trace-back investigation, with the support of affected countries, the European Centre for Disease Prevention and Control, the European Commission, and the Federal Institute for Risk Assessment.

The authority has also recommended that affected countries could consider implementing mitigating measures at a national level, given the epidemiological and laboratory evidence of contaminated frozen berries, the risk to human health, and ongoing transmission with increasing geographical spread.

The update says, “In accordance with their national guidelines, member states may consider active or passive immunisation of those in close contact with cases in order to prevent secondary transmission.”

Other steps suggested for affected countries to consider included highlighting the risks to the public, recommending heat treatment of frozen berries before consumption, and implementing an enhanced sampling scheme for frozen berries at the processing and distribution level.

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