Two people have died so far this year in Lithuania from listeriosis, according to the Centre for Communicable Diseases and AIDS (ULAC).

Both deaths were in people older than 70 years of age. From 2013 to 2018, listeriosis was diagnosed in 57 people and 13 of them died.

Listeriosis is a relatively rare but potentially severe foodborne disease that has been reported in increasing numbers in European countries since 2008. In 2016, 2,536 cases were recorded including 247 deaths and according to the European Center for Disease Prevention and Control (ECDC).

The main source of Listeria infection, according to European officials, is food of animal origin that has not been heat-treated, especially cold-smoked or dried meat products, unpasteurized milk and raw milk products, or cold-smoked fish.

According to ULAC data, 20 cases of listeriosis were registered in Lithuania last year. The number of infection has ranged from five in 2009 to 20 in 2018.

The agency previously revealed the number of people sick from Campylobacter and Salmonella infections had increased by about 20 percent in Lithuania this year. A total of 434 cases of salmonellosis and 630 patients with campylobacteriosis were reported during the first seven months of 2019.

ECDC’s Listeria assessment
Meanwhile, the ECDC has published results of an external quality assessment on Listeria monocytogenes typing for laboratories providing data to the Food- and Waterborne Diseases and Zoonoses Network (FWD-Net) managed by the agency.

Surveillance data are reported by member states to The European Surveillance System (TESSy), including molecular typing data. This molecular surveillance system relies on the capacity of labs providing data to FWD-Net to produce comparable typing results. The objective is to assess the quality and comparability of typing data reported by public health national reference labs that are part of the network.

In March 2019, ECDC launched the possibility of submitting WGS variables for Listeria monocytogenes to TESSy to be used for EU-wide surveillance and cross-sector comparison.

The latest assessment contained a molecular typing-based cluster analysis using pulsed-field gel electrophoresis (PFGE) and/or whole genome sequencing (WGS)-derived data as well as serotyping.

Eighteen labs signed up and 17 completed the exercise, representing a drop in participation from the previous assessment and an even larger decrease from the one before that. The decline in participants may have been caused by adding WGS or removing PFGE as an independent part.

Molecular serotyping results were provided by 13 participants. Only four did both conventional and molecular serotyping. The performance of conventional serotyping was highest, with 100 percent correct results. A total of 77 percent of labs correctly serotyped all test isolates by molecular method.

Seven laboratories used PFGE for cluster analysis and four also reported cluster analysis based on WGS data. Only one lab did not identify the correct cluster using PFGE.

Comparing core genome multilocus sequence type (cgMLST) result of Illumina and Ion Torrent data revealed differences, which suggests lower inter-laboratory comparability across sequencing platforms, according to ECDC.

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