Listeria Spp. Flashcards
What is the oxygen requirement for Listeria?
Facultative anaerobe
Where is Listeria typically found in the body?
Normal flora in the GIT, wide temp. Range of growth (0-50 Celsius)
Is Listeria resistant to harsh conditions?
YES
What host does L. monocytogenes infect?
Multiple hosts INCLUDING humans
L. ivanovii is associated with what issue in ruminants?
Ruminant Abortion
T/F: Listeria are ubiquitous in the environment and are carried in a wide variety of animals as asymptomatic enteric carriers
TRUE
How do outbreaks of L. Monocytogenes typically occur?
After feeding Poor Quality Silage
Listeria monocytogenes is an economically important disease associated with _______________ occurrence?
SEASONAL (winter)
L. monocytogenes cause what conditions?
Septicemia, abortion, and encephalitis
T/F: The pathogenesis of Listeria is Invasive
TRUE: Listeria is facultative intracellular (persists in macrophages)
What species do you typically find encephalitis associated with Listeria?
Most common in cattle and ovine
Encephalitis with Listeria can lead to Neuro symptoms. What are the symptoms (2)?
- ) Circling Disease - walking around in circles
2. ) Unilateral trigeminal and facial nerve paralysis - drooping of eyelid/ear, drooling, strabismus, nystagmus
What are the 3 disease presentations associated with Listeria spp.?
Encephalitis
Abortion
Septicemia
Abortion related to Listeria causes what condition?
Listeria spreads to the uterus, penetrates the placenta to the fetal liver to cause FOCAL HEPATIC NECROSIS
Septicemia related to Listeria is found in what age group of animals?
In neonate as a continuation of fetal infection
Common in monogastrics
What are the Virulence Factors assoc. with Listeria?
Act A
Internalin
Listeriolysin O (hemolysin)
What is the action of Act A?
Allows for intracellular movement to adjacent cells through bacterially host induced actin polymerization
Pregnancy toxemia is a diagnosis typically of_______?
Ewes
Ketosis is a diagnosis associated with which species?
Cattle
What virulence factor allows for intracellular movement to adjacent cells through bacterially host induced actin polymerization?
ACT A
In order to diagnose Listeria, what area of the body do you test?
THE BRAIN STEM - do a Listeria enrichment culture **
If animal is septic, culture liver and spleen
In ruminants, purulent endophthalmitis (cloudy eye) is usually unilateral or bilateral?
Unilateral
What do you expect to find in a L. monocytogenes histopatholgy?
Micro-abscesses in the brain
Is Listeria zoonotic?
YES! Highly zoonotic! Source: Unpasteurized milk and meat products
What would you use to treat L. monocytogenes?
Penicillin (susceptible to penicillin)
OR
Ampicillin + Gentamicin (good choice)
When would you not treat L. monocytogenes in ruminants?
Not treated when assoc. with CNS disease
Are vaccines available for Listeria spp?
NO. Cell-mediated immunity is more important.
Avoid poor quality silage
