Listeria and Erysipelothrix

Question 1

what does Listeria monocytogenes look like under a microscope with a gram stain?

Answer 1

gram positive short rod

Question 2

what are the reservoirs of Listeria monocytogenes?

Answer 2

soil
gastrointestinal tract of carriers (animals and humans)

Question 3

what are the common modes of transmission for Listeria monocytogenes?

Answer 3

horizontal: fecal-oral
vertical: placenta, vaginal fluids

Question 4

how can the host shed Listeria moncytogenes?

Answer 4

feces
urine
milk
uterine fluids
aborted fetuses
nasal discharge

Question 5

what is the most frequently recognized form of listeriosis?

Answer 5

listeric (meningo) encephalitis in adult ruminants

Question 6

what is the mortality rate of listeric (meningo) encephalitis?

Answer 6

50-70%

Question 7

what characterizes the neurologic signs of listeric (meningo) encephalitis usually?

Answer 7

unilateral
localize to brain stem
affect cranial nerves

Question 8

what is the pathogenesis of listeric encephalitis?

Answer 8

eat contaminated food
Listeria monocytogenes enters abrasions in oral cavity
track trigeminal nerve
brainstem
necrosis and neutrophilic microabscesses

Question 9

what are some differential diagnoses for listeric encephalitis?

Answer 9

thromboembolic meningoencephalitis due to Histophilus somni
cerebral abscess due to other bacteria
rabies

Question 10

what does listeric abortion usually occur in?

Answer 10

small ruminants

Question 11

what is the primary site of infection of Listeria monocytogenes with listeric abortion?

Answer 11

uterus, placenta
abortion of autolyzed fetus

Question 12

who does septicemic listeriosis occur in?

Answer 12

primarily very young animals

Question 13

what are the clinical signs of septicemic listeriosis?

Answer 13

fever
depression/lethargy
injected mucous membranes
+/- hemorrhagic gastroenteritis in calves

Question 14

what is the target organ of septicemic listeriosis?

Answer 14

liver: hepatic necrosis

Question 15

what diagnostic samples can be taken for listeric abortion?

Answer 15

culture, cytology of abomasal contents from fetus
histopath and gram stain liver, spleen, lungs

Question 16

what are the well known Listeria monocytogenes virulence factors?

Answer 16

listeriolysis O=LLO
actin comet tails

Question 17

is Listeria a reportable disease?

Answer 17

yes

Question 18

who does swine erysipelas impact?

Answer 18

growing and adult swine

Question 19

up to ______ of pigs in intensive swine production areas are asymptomatic carriers of Erysipelothrix rhusiopathiae

Answer 19

50%

Question 20

where do carriers of Erysipelothrix rhusiopathiae harbor it?

Answer 20

tonsils and shed in oronasal secretions and feces

Question 21

what is the virulence factor of Erysipelothrix rhusiopathiae?

Answer 21

neuraminidase

Question 22

what characterizes the acute form of erysipelas?

Answer 22

septicemia
fever
skin lesions (diamond)

Question 23

what characterizes the chronic form of erysipelas?

Answer 23

arthritis
vegetative valvular endocarditis

Question 24

what are the differential diagnoses for erysipelas (diamond skin disease in swine)?

Answer 24

septicemia due to Salmonella, Streptococcus suis
classical swine fever
glasser’s disease

Question 25

how is diamond skin disease controlled?

Answer 25

vaccine

Question 26

what can you see with erysipelas in poultry?

Answer 26

sudden death (septicemia) swollen joints endocarditis

Question 27

is erysipelas zoonotic?

Answer 27

yes

Question 28

who can carry erysipelas (poultry) in semen?

Answer 28

toms (male turkeys)

Question 29

how is erysipelas prevented in poultry?

Answer 29

antibiotics vaccine

Question 30

how does thromboembolic meningoencephalitis due to Histophilus somni differ from listeric encephalitis?

Answer 30

Histophilus spp does not have a preferred site of infection in the brain distinguish by other lab tests

Question 31

how do cerebral abscesses due to other bacteria differ from listeric encephalitis?

Answer 31

Listeria: usually unilateral cranial nerve signs cerebral abscess: mentation changes

Question 32

how can you differentiate rabies from listeric encephalitis?

Answer 32

rabies usually reflects damage to cortical neurons: mentation changes not unilateral

Question 33

does metritis from listeric abortion have effects on subsequent reproduction?

Answer 33

no

Question 34

how long can Listeria be shed in vaginal secretions and milk?

Answer 34

a month

Question 35

what makes Listeria monocytogenes hard to get rid of?

Answer 35

persists in environment, food, and gastrointestinal tract likes low temperatures resistant to drying and heat tolerates wide pH range

Question 36

what does listeriolysin O do?

Answer 36

allows Listeria to escape phagosome and then replicate in cytoplasm pore-forming protein toxin

Question 37

what do actin comet tails allow Listeria to do?

Answer 37

hijack and polymerize actin to move and hide

Question 38

what is the host response to Listeria moncytogenes?

Answer 38

cellular necrosis and neutrophilic inflammation

Question 39

who is clinical disease of Listeria seen in usually?

Answer 39

ruminants

Question 40

how do humans usually get listeriosis?

Answer 40

food

Question 41

what does neuraminidase from Erysipelothrix rhusiopathiae do?

Answer 41

important for attaching and invading cleaves sialic acid +/- nutrional requirements, disruption host functions

Question 42

what are the forms of Erysipelas in swine?

Answer 42

acute chronic