More than half of the severe listeriosis cases in the European Union belong to clusters, many of which are not being picked up fast enough by the current surveillance system, suggests a new article published in Eurosurveillance.
The large-scale study looked into listeriosis epidemiology through whole genome sequencing and found that this method, when implemented at EU-level, could lead to faster detection of multi-country outbreaks, saving up to 5 months of the investigations.
The study, coordinated by the European Centre for Disease Prevention and Control (ECDC), analysed 2 726 human Listeria monocytogenes isolates from 27 countries between 2010 and 2015.
It found that slightly under 50% of the cases are isolated whereas the remaining half of cases is clustered together. Around one third of the cases that were identified as part of a cluster affected more than one country, often lasting for several years. However, only two listeriosis outbreaks were reported in the EU in 2016 and five in 2015, which suggests that many of them have gone undetected.