Listeria surveillance: new EU-wide study reveals that most outbreaks remain undetected

A large-scale study coordinated by the European Centre for Disease Prevention and Control (ECDC) found that more than half of the severe listeriosis cases in the EU belong to clusters, many of which are not being picked up fast enough by the current surveillance system. Listeriosis is a relatively rare but potentially severe food-borne disease that has been reported in increasing numbers in EU/EEA countries since 2008. In 2016, 2,536 cases were reported, including 247 deaths.

The study examined 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. A more timely detection of clusters would potentially limit the occurrence of further cases from the same, common food source.

The study analysed 2,726 human Listeria monocytogenes isolates from 27 countries between 2010 and 2015. It found that slightly fewer than 50% of the cases were isolated, whereas the remaining cases were 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, suggesting that many of them have gone undetected.

Source: ECDC, 20 August 2018