Some foods, including ready-to-eat refrigerated foods, unpasteurized (raw) milk, and foods made with unpasteurized milk, can often be contaminated with Listeria monocytogenes.
Listeriosis is a saprozoonotic infectious disease of humans and animals caused by pathogenic representatives of the genus Listeria, characterized by multiple sources and reservoirs of infection, a variety of routes and factors of transmission of the pathogen, polymorphism of clinical manifestations, high mortality in newborns and people with immunodeficiencies with the possible development of visceral, nervous, glandular, gastroenteric and mixed forms, as well as asymptomatic carriage of Listeria.
The causative agents of listeriosis are microorganisms of the genus Listeria. Listeria is resistant to various physical and technological influences, including low temperatures; they persist for a long time in all environmental objects: soil, water, pathological material from dead animals, feed.
The greatest importance in the spread of listeriosis is played by the ability of the pathogen to actively multiply and persist for a long time in various food products, especially at +4 ° C, storage in the refrigerator, including in products packaged in barrier films that limit the access of oxygen (under vacuum, in a modified gas atmosphere).
The main reservoir of the pathogen in nature is many species of synanthropic and wild rodents. Listeria is found in foxes, minks, arctic foxes, wild ungulates, and birds. Listeriosis affects domestic and farm animals (pigs, small and large livestock, horses, rabbits, and less commonly cats and dogs), as well as domestic and ornamental poultry. Listeria has also been found in fish and seafood (shrimp).
The source of infection for humans is farm animals - sick and asymptomatic carriers and rodents.
Listeriosis infection can be transmitted by blood-sucking arthropods (ixodid and gamas ticks), as well as various types of fleas and lice.
A person with listeriosis or an asymptomatic carrier also poses an epidemiological danger.
With listeriosis, there are multiple mechanisms of transmission of the infectious agent: fecal-oral, contact-household, aspiration, transplacental.
Listeria enters the human body primarily through the gastrointestinal tract; in rare cases, penetration through the respiratory system, mucous membranes, and damaged skin is possible. Human infection occurs as a result of: - consumption of infected products of animal origin (dairy products, meat products, poultry products), vegetables and fruits, seafood), mainly ready-to-eat products; - inhalation of dust contaminated with the pathogen; - contact with sick animals or carriers of the causative agent of listeriosis; intrauterine transmission of the pathogen through the placenta, - contact of newborn children with infected care items and medical instruments in maternity hospitals.
The most threatened groups at risk of contracting listeriosis are pregnant women, newborns, people over 50 years of age, and people with immunodeficiency.
Occupational diseases of listeriosis are possible among veterinary specialists, workers in meat processing and dairy products, livestock farms and other enterprises that keep animals.
The clinical picture of listeriosis is characterized by polymorphism; the clinical forms of the disease depend on the predominance of lesions of individual organs and systems. There are visceral, nervous, glandular, gastroenteric and mixed forms, as well as asymptomatic carriage of listeria.
The main clinical manifestations of listeriosis in humans are meningitis, meningoencephalitis, sepsis; miscarriages and stillbirths in pregnant women.
How to reduce the risk of contracting listeriosis?
1. Cooling at appropriate temperature. Low temperatures slow down the growth of Listeria. To control the temperature in the refrigerator, you need to install a thermometer. Your refrigerator should be at +2+4°C and your freezer at -18°C.
2. Use ready-to-eat products within 2 hours! Use ready-to-eat, refrigerated food before the date printed on the package. The longer they are kept in the refrigerator, the greater the chance that listeria will grow.
3. Keep your refrigerator clean
Clean your refrigerator regularly. Clean up spills immediately. This is especially important because Listeria has no place to grow and then spread to other foods. Clean the interior walls and shelves with hot water and mild liquid dishwashing detergent, rinse, then dry with a clean cloth or paper towel.
Be healthy!
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