In response to the diagnosis of six individuals with Listeria infections, authorities in Iceland have issued a cautionary advisory. The Icelandic Food and Veterinary Authority (MAST) aims to heighten awareness of this disease, particularly among vulnerable groups, and highlight preventive measures that can be undertaken by food companies.
The identified at-risk groups include individuals with compromised immune systems, those under immunosuppressive medication or cancer treatment, expectant mothers, young children, and the elderly.
As of now, the precise source of the foodborne infection remains undetermined. Officials have refrained from specifying whether these cases represent isolated incidents or constitute part of a larger outbreak.
In prior years, Iceland typically reported between two to five cases annually. However, in 2024, the number surged to six cases diagnosed through blood culture at Landspítala’s bacteriology and virology department. Of the cases for which information is available, four are male and one is female, with ages ranging from 70 to 85 years old.
Listeria infection became a notifiable disease in Iceland in 1997. A study spanning from 1978 to 2000 documented 40 cases, with a mortality rate of approximately 33 percent.
An e-newsletter issued by the Directorate of Health (Embætti landlæknis) highlighted the escalating incidence of Listeria across Europe, particularly affecting older demographics. The severity of the illness in susceptible individuals underscores the urgency of this concern.
The directive emphasized the importance of educating high-risk groups about the association between Listeria and certain uncooked foods, including soft and raw milk cheeses, vegetables, salads, as well as ready-to-eat items like sandwiches and smoked salmon.
MAST advised food companies to maintain stringent hygiene practices, including thorough cleaning of food contact surfaces and vigilant monitoring for biofilms, which can facilitate the survival of Listeria. Regular maintenance routines were also stressed to prevent bacterial survival and proliferation in production environments.
Furthermore, companies involved in the production of ready-to-eat foods were advised to conduct regular monitoring of Listeria in both the production environment and the products themselves, with the frequency of analysis tailored to individual risk assessments.
Consumers were encouraged to maintain refrigerator temperatures below 4 degrees Celsius (39.2 degrees Fahrenheit), refrain from consuming foods past their use-by dates, and ensure that prepared dishes are heated to at least 75 degrees Celsius (167 degrees Fahrenheit).
About Listeria Infections
Listeria monocytogenes contamination may not manifest visually or through odor in affected food items, yet it can lead to severe and occasionally life-threatening infections. Individuals experiencing symptoms of Listeria infection are urged to seek medical attention and inform healthcare providers of potential Listeria exposure.
Given the incubation period of up to 70 days following Listeria exposure, individuals should remain vigilant for symptoms during this timeframe. Symptoms of listeriosis may include vomiting, nausea, persistent fever, muscle aches, severe headache, and neck stiffness. Diagnosis of Listeria infections necessitates specific laboratory tests, as symptoms can mimic those of other illnesses.
Particular attention should be paid to pregnant women, the elderly, young children, and individuals with weakened immune systems, including cancer patients, as they are at heightened risk of severe illness, life-threatening infections, and associated complications. Although infected pregnant women may only experience mild flu-like symptoms, the consequences can include premature delivery, neonatal infection, or even stillbirth.
