Listeria Spp.

Question 1

What is the oxygen requirement for Listeria?

Answer 1

Facultative anaerobe

Question 2

Where is Listeria typically found in the body?

Answer 2

Normal flora in the GIT, wide temp. Range of growth (0-50 Celsius)

Question 3

Is Listeria resistant to harsh conditions?

Answer 3

YES

Question 4

What host does L. monocytogenes infect?

Answer 4

Multiple hosts INCLUDING humans

Question 5

L. ivanovii is associated with what issue in ruminants?

Answer 5

Ruminant Abortion

Question 6

T/F: Listeria are ubiquitous in the environment and are carried in a wide variety of animals as asymptomatic enteric carriers

Answer 6

TRUE

Question 7

How do outbreaks of L. Monocytogenes typically occur?

Answer 7

After feeding Poor Quality Silage

Question 8

Listeria monocytogenes is an economically important disease associated with _______________ occurrence?

Answer 8

SEASONAL (winter)

Question 9

L. monocytogenes cause what conditions?

Answer 9

Septicemia, abortion, and encephalitis

Question 10

T/F: The pathogenesis of Listeria is Invasive

Answer 10

TRUE: Listeria is facultative intracellular (persists in macrophages)

Question 11

What species do you typically find encephalitis associated with Listeria?

Answer 11

Most common in cattle and ovine

Question 12

Encephalitis with Listeria can lead to Neuro symptoms. What are the symptoms (2)?

Answer 12

1. ) Circling Disease - walking around in circles

2. ) Unilateral trigeminal and facial nerve paralysis - drooping of eyelid/ear, drooling, strabismus, nystagmus

Question 13

What are the 3 disease presentations associated with Listeria spp.?

Answer 13

Encephalitis
Abortion
Septicemia

Question 14

Abortion related to Listeria causes what condition?

Answer 14

Listeria spreads to the uterus, penetrates the placenta to the fetal liver to cause FOCAL HEPATIC NECROSIS

Question 15

Septicemia related to Listeria is found in what age group of animals?

Answer 15

In neonate as a continuation of fetal infection

Common in monogastrics

Question 16

What are the Virulence Factors assoc. with Listeria?

Answer 16

Act A
Internalin
Listeriolysin O (hemolysin)

Question 17

What is the action of Act A?

Answer 17

Allows for intracellular movement to adjacent cells through bacterially host induced actin polymerization

Question 18

Pregnancy toxemia is a diagnosis typically of_______?

Answer 18

Ewes

Question 19

Ketosis is a diagnosis associated with which species?

Answer 19

Cattle

Question 20

What virulence factor allows for intracellular movement to adjacent cells through bacterially host induced actin polymerization?

Answer 20

ACT A

Question 21

In order to diagnose Listeria, what area of the body do you test?

Answer 21

THE BRAIN STEM - do a Listeria enrichment culture **

If animal is septic, culture liver and spleen

Question 22

In ruminants, purulent endophthalmitis (cloudy eye) is usually unilateral or bilateral?

Answer 22

Unilateral

Question 23

What do you expect to find in a L. monocytogenes histopatholgy?

Answer 23

Micro-abscesses in the brain

Question 24

Is Listeria zoonotic?

Answer 24

YES! Highly zoonotic! Source: Unpasteurized milk and meat products

Question 25

What would you use to treat L. monocytogenes?

Answer 25

Penicillin (susceptible to penicillin)
OR
Ampicillin + Gentamicin (good choice)

Question 26

When would you not treat L. monocytogenes in ruminants?

Answer 26

Not treated when assoc. with CNS disease

Question 27

Are vaccines available for Listeria spp?

Answer 27

NO. Cell-mediated immunity is more important.

Avoid poor quality silage