The severity of listeriosis varies and in some cases can be fatal, especially among the elderly, people with weakened immune systems or chronic diseases. Listeriosis can be particularly dangerous for pregnant women and their newborn babies, leading to serious complications with their pregnancy, including miscarriage and stillbirth.
People can get infected by eating the following:
What is listeriosis and how can it be prevented? Listeriosis is a serious infection caused by a bacterium Listeria monocytogenes. The bacteria is found in soil and water and some animals, including poultry and cattle. It can be present in raw milk and foods made from raw milk.
A Listeria infection can lead to meningitis, an inflammation of the membranes surrounding the brain. If a newborn infant is infected with Listeria, long-term consequences may include mental retardation, seizures, paralysis, blindness, or deafness.
Listeria monocytogenes evades and modulates the immune response first by creating an intracellular niche that prevents recognition by the immune system and in turn, limits immune responses to infection by modulating host signalling leading to events that benefit the pathogen and favour a successful infection.
The prevailing notion is that CD8 T cells mediate anti-listerial immunity through two synergistic mechanisms: (1) lysing infected target cells via perforin and granzymes to expose intracellular bacteria for killing by activated macrophages, and (2) secreting IFNγ to activate macrophages [60].
Abstract. Listeria monocytogenes is a Gram-positive bacterium responsible for severe infections in human and a large variety of animal species. It is a facultative intracellular pathogen which invades macrophages and most tissue cells of infected hosts where it can proliferate.
The primary immune response to infection with L. monocytogenes is mediated by two main CD8+ T-cell subpopulations: one is restricted by MHC class Ia molecules, and the other is restricted by the MHC class Ib molecule H2–M3. H2–M3-restricted T cells make an important contribution to the primary immune response to L.
Does past infection with listeriosis make a person immune? Past infection does not appear to make a person immune. People can be reinfected if exposed to the Listeria bacteria again.
Listeria is transmitted from contaminated food. After the food has been ingested, the bacterium crosses the intestinal wall before spreading to other organs of the body including the liver, spleen, brain and placenta (in pregnant women) where it is able to cause further disease.
Two species of Listeria are pathogenic; L. monocytogenes infects humans and animals, and L. ivanovii has been considered to infect ruminants only.
Listeria monocytogenes can survive and grow over a wide range of environmental conditions such as refrigeration temperatures, low pH and high salt concentration. This allows the pathogen to overcome food preservation and safety barriers, and pose a potential risk to human health.