The European Centre for Disease Prevention and Control (ECDC) has identified a microbiological link between an outbreak of nine Listeria monocytogenes ST1247 cases in Denmark and nine additional cases reported between 2014 and 2018 in Estonia (two) Finland (two), France (one) and Sweden (four).
Whole genome sequencing (WGS) analysis performed at the national level and by ECDC found all isolates from the 18 cases within two allelic differences from each other (core genome MLST using Moura scheme, 1540 of 1748 loci detected in all 18 isolates). The latest case was reported in Denmark in February 2019.
A large-scale study led by ECDC on WGS shows that most Listeria outbreaks remain undetected. The study, published in 2018, suggested 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.
L. monocytogenes causes listeriosis, which primarily affects pregnant women, newborns, and adults with a weakened immune 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.
Source: ECDC, 27 March 2019