Listeriosis (synonyms:Listeria monocytogenes; neonatal listeriosis; acute septic listeriosis; chronic septic listeriosis; glandular listeriosis; cutaneous listeriosis; central nervous listeriosis; ICD-10-GM A32.9: Listeriosis, unspecified) is an infectious disease that occurs sporadically in humans and is caused by bacteria of the genus Listeria. These are Gram-positive, non-spore-forming rod-shaped bacteria. The species Listeria monocytogenes is among the most important pathogens of this genus.
Occurrence: Listeria are found primarily in domestic and wild animals. They are also widespread in the agricultural sector. In particular, they can be detected in soil, plants and wastewater. Frequently, the bacteria are found in animal feed.
The bacteria can be detected in the stool of infected individuals for months.
Transmission of the pathogen (route of infection) can be fecal-oral (infections in which pathogens excreted in feces (fecal) are ingested by mouth (oral)) or through consumption of contaminated food (predominantly animal (raw) foods, but also plant foods such as pre-cut salads).
The incubation period (time from infection to onset of disease) in the context of foodborne infection is between 3 and 70 days (usually 3 weeks).
The duration of illness is usually up to 1 week.
Sex ratio: In the age group between 20 and 39 years, predominantly women are affected (mostly pregnancy listeriosis). In the older age groups (> 50 years), men are more frequently affected than women.
Peak incidence: The disease occurs predominantly in the elderly (> 60 years) and immunocompromised individuals, pregnant women and their newborns.
The incidence (frequency of new cases) is approximately 0.4 cases per 100,000 population per year. Pregnant women are 13 times more likely to be infected with Listeria monocytogenes than the general population. Neonatal listeriosis has an incidence of 3.7 illnesses per 100,000 newborns per year.
Duration of infectivity (contagiousness): individuals infected with the pathogen may excrete it in the stool for several months.
Course and prognosis
Different forms of progression can be distinguished:
- Acute septic listeriosis
- Chronic septic listeriosis
- Glandular listeriosis
- Cutaneous listeriosis
- Neonatal listeriosis
- Central nervous listeriosis
In healthy people, the disease is usually without symptoms and mild. Often it is not even noticed and heals spontaneously (by itself). In immunodeficiency, the course of the disease can be severe and the prognosis is less favorable. Infections during pregnancy (gestational listeriosis) can lead to miscarriage, premature birth, stillbirth, and birth of a damaged child (neonatal listeriosis) as a result of intrauterine (in the womb via the placenta) or perinatal (during birth) transmission.
The lethality (mortality based on the total number of people with the disease) for neonatal listeriosis is 30 to 50%. Even in immunocompromised individuals with a complicated course of infection, the lethality is approximately 30%.
In Germany, only direct detection of the pathogen from blood, cerebrospinal fluid, or other normally sterile materials, as well as from smears taken from the newborn, is reportable under the Infection Protection Act (IfSG). For each newborn with laboratory-diagnostic evidence of Listeria monocytogenes, the mother (regardless of her clinical picture and laboratory-diagnostic evidence) must also be transmitted as a clinical-epidemiologically confirmed disease.