Infections of the Nervous System I (10)

Question 1

What is the most common form of listeriosis in ruminants?

Answer 1

listeriosis monocytogenes

Question 2

Where does listeriosis monocytogenes infect? It is [localized/generalized]

Answer 2

localized ascending asymmetric infection of the brain stem

Question 3

Listeria is gram-[positive/negative]

Answer 3

gram-positive

Question 4

What does Listeria tolerate temperature and pH- wise?

Answer 4

4C to 45C
pH 5.5 to 9.6

Question 5

What is one way Listeria is identified?

Answer 5

hydrolyzes esculin

Question 6

Outbreaks of Listeria is often related to what?

Answer 6

outbreaks of silage feeding

Question 7

What is this?

Answer 7

Listeria

notice how it’s gram-positive and non-spore forming rod

Question 8

T/F: Listeria grows on blood agar

Answer 8

TRUE

Question 9

What are the two Listeria spp. discussed?

Answer 9

L. monocytogenes

L. ivanovii

Question 10

Contrast listeria monocytogenes and listeria ivanovii

Answer 10

monocytogenes: more pathogenic, CNS infection, disease in animals and humans

ivanovii: less pathogenic, NO CNS infection, abortion

Question 11

Which species does ivanovii cause abortion in?

Answer 11

sheep and cattle

Question 12

What 3 major syndromes cause listeriosis in ruminants?

Answer 12

neural form

visceral form

abortions

Question 13

What is the neural form of Listeriosis?

Answer 13

meningoencephalitis in ruminants sometimes called “circling disease” or “silage disease”

Question 14

What is the visceral form of Listeriosis? This is seen specifically in who?

Answer 14

septicemia, seen in neonates especially calves, lambs, foals, and piglets

Question 15

Listeriosis causes abortions in _______

Answer 15

ruminants

Question 16

What are clinical signs of neural listeriosis?

Answer 16

depression
drooping ears
animal holds head to one side
protrusion of tongue
salivation
paralysis of face

Question 17

Lesions in the neural form are in the brain stem, often unilateral, and are composed of ______ and ________

Answer 17

microabscesses

perivascular lymphocytic cuffing

Question 18

Regarding listeriosis, abortion, without evidence of systemic illness, may occur up to ___ days after infection

Answer 18

12

Question 19

What is septicemic listeriosis? It is most commonly encountered in who?

Answer 19

short incubation of 2-3 days

lesions include micro abscesses of heart, liver, and kidneys

lambs - sometimes pregnant sheep too

Question 20

Which species may sometimes encounter ocular listeriosis and keratoconjunctivitis?

Answer 20

cattle
sheep

Question 21

A sheep has been diagnosed with listeriosis. Describe some of the clinical signs that confirms how you know

Answer 21

has right facial nerve paralysis
drooped right ear
right eye is showing no reaction to flash
atony of right nostril

Question 22

Another sheep is apathetic and also has listeriosis. What can you see that is also a clinical sign?

Answer 22

encephalitis

Question 23

An ovine medulla is being observed under the microscope. What do you notice that is indicative of listeriosis? Which specific syndrome?

Answer 23

perivascular cuffing

neural form

Question 24

Septicemia was observed post-mortem on a lamb. Listeriosis was confirmed. Which syndrome of listeriosis is septicemia related to?

Answer 24

visceral form of listeriosis

Question 25

What is the pathogenesis of listeriosis?

Answer 25

ingestion of contaminated feed and may result in septicemia, encephalitis, or abortion

Question 26

Where do organisms probably penetrate when infected with listeriosis?

Answer 26

M cells in Peyer’s patches

Question 27

How does listeriosis spread?

Answer 27

via lymph and blood to various tissues

Question 28

How does listeriosis spread in pregnant animals?

Answer 28

transplacental transmission

Question 29

What are the 2 ways CNS infections can occur in listeriosis?

Answer 29

1. bacteremia
2. oral mucosal invasion possibly through dental pulp, followed by trigeminal nerve infection with axonal transport to the brain especially the midbrain, pons, and medulla oblongata

Question 30

In Listeriosis, there is a high incidence of _______

Answer 30

intestinal carriers

Question 31

What are the natural reservoirs for L. monocytogenes?

Answer 31

soil

mammalian tracts

*both contaminate vegetation

Question 32

How does animal-to-animal transmission of Listeriosis occur?

Answer 32

fecal-oral route

Question 33

What enhances multiplication of L. monocytogenes?

Answer 33

less acidic pH of spoiled silage

Question 34

What kind of parasite is listeriosis?

Answer 34

facultative intracellular parasite

Question 35

How does listeriosis invade?

Answer 35

invades epithelial cells and/or phagocytic cells
escapes from phagosome
begins replication in cytoplasm

Question 36

How can listeriosis spread? Via ____

Answer 36

intracellularly

the formation of actin tails (using host cell actin) that propel bacterium forward and eventually through the cell membranes into a new host cell

Question 37

What is the diagnosis identification criteria for listeria monocytogenes?

Answer 37

colonies are small, smooth, and flat with a blue-green color when illuminated obliquely

Question 38

Listeria tests are coagulase [positive/negative]

Answer 38

positive

Question 39

What is the treatment of choice for listeria? What else is required and why?

Answer 39

penicillin

high doses - because of the difficulty in achieving minimum bactericidal concentrations in the brain

Question 40

What does listeriosis recovery depend on?

Answer 40

early, aggressive antibiotic treatment

Question 41

What discourages treatment of L. monocytogenes?

Answer 41

a more acidic pH - corn ensiled before being too mature and grass silage containing additives

Question 42

T/F: Not all human cases of listeriosis are due to an animal source

Answer 42

TRUE