Tracing of food items in connection to the multinational hepatitis A virus outbreak in Europe

Abstract

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.

Application of an Optimized Direct Lysis Method for Viral RNA Extraction Linking Contaminated Dates to Infection With Hepatitis A Virus

“…Due to the estimated low contamination level in foods and the low efficiency of common methods to recover viral RNA, the characterization by sequencing of detected viral RNA in food materials may often be more difficult than in human stool or blood samples (EFSA, 2014). Previously, we reported that the optimized direct lysis method applied in this study was significantly more efficient in recovering RNA of spiked model viruses on a selection of types of fruits compared to the ISO standard (Rajiuddin et al, 2020).…”

“…In recent years, consumption of HAV contaminated fruit imported from endemic areas has been identified as the source of several large and sometimes multistate outbreaks of HAV in Europe (EFSA, 2014;Severi et al, 2015). For example, HAV contaminated frozen berries caused 1,589 cases including two deaths in 13 EU/EEA countries during 2013-2014 (Severi et al, 2015), 71 cases in four Nordic countries including Denmark during 2012-2013 (Lassen et al, 2013) and 14 cases in the Netherlands in 2017 (Mollers et al, 2018).…”

“…Attempts to detect and characterize HAV in suspected food products, identified by case control studies, to conduct a genetic comparison between HAV strains identified in clinical and food samples have often been unsuccessful, although it is essential to verify the origin of the foodborne disease (Petrignani et al, 2010;Gallot et al, 2011;Collier et al, 2014). One reason for this can be the un-availability of relevant food samples for laboratory analyses due to long lag time (2-6 weeks) between infection and onset of symptoms (EFSA, 2014). Other reasons may include uneven distribution of virus in suspected food, and low titer or purity of extracted viral RNA for un-inhibited HAV detection by reverse transcription (RT)-qPCR and characterization by sequencing (Schrader et al, 2012;EFSA, 2014).…”

“…One reason for this can be the un-availability of relevant food samples for laboratory analyses due to long lag time (2-6 weeks) between infection and onset of symptoms (EFSA, 2014). Other reasons may include uneven distribution of virus in suspected food, and low titer or purity of extracted viral RNA for un-inhibited HAV detection by reverse transcription (RT)-qPCR and characterization by sequencing (Schrader et al, 2012;EFSA, 2014).…”

A Review of Significant European Foodborne Outbreaks in the Last Decade

“…This outbreak, known as the largest HAV outbreak in Europe (74), led the European Commission to ask EFSA to coordinate an extensive tracing exercise. The aim was to identify the berries contaminated with the hepatitis A virus (mixed frozen berries), to trace them back to their place of production, and to find a point of contamination (37). Given the complexity of the event, the type of involved food items, and the epidemiological evidences available at the time of the exercise, the trace-back analysis could not identify a single point-source of contamination.…”