Category Archives: foodbourne outbreak

Eurosurveillance

Listeriosis is a severe bacterial infection caused by Listeria monocytogenes (Lm), usually via consumption of food contaminated with the bacterium. However, other ways of transmission than food-borne have been reported [1]. Listeria species are ubiquitous in the environment and many animals shed Lm in their faeces. Infections are often associated with raw, chilled or ready-to-eat (RTE) foods. Symptoms develop within 1–70 days after eating food contaminated with Lm [2]. The disease can manifest as severe, invasive illness, more likely in elderly people, pregnant women, unborn or newborn babies and people with weakened immune systems [3]. In these persons, listeriosis may present as septicaemia or meningitis and lead to high hospitalisation and mortality rates.

In 2021, an incidence of 0.5 per 100,000 population was reported for listeriosis in the European Union/European Economic Area (EU/EEA), while the incidence in Finland was 1.3 per 100,000 [4].

Listeriosis cases have been reported in healthcare facilities [5–11]. Two healthcare-associated Lm outbreaks have been reported in Finland during the last three decades. In 1999, a large hospital outbreak occurred with six deaths in 25 cases of invasive listeriosis. The source of the outbreak was butter which may have been contaminated after pasteurisation [12]. In 2012, RTE meat jelly was suspected to be the source of a hospital outbreak affecting 25 people [9].