Gram Pos: Listeria, Erysipelothrix

Question 1

Describe the key bacteria characteristics of listeria.

Answer 1

-gram pos coccobacillary rods
-facultative anaerobes
-catalase (+) & oxidase (-)
-tumbling motility (1-4 flagella) at 25c
-pH between 5.5-9.6
-temp between 0-50c = psychrophilic (food borne)
-ubiquitous in environment (soil) & in GIT in humans & animals (wide range) asymptomatic
-found in herbage, feces, sewage, water
-resistance to harsh environment
-poor silage & food = common source
-CS: septicemia, abortion, encephalitis

Peri flagella

Question 2

Describe the virulence factors & pathogenesis of listeria.

Answer 2

-facultative intracellular bacteria in macrophages
-pathogenicity = intracellular replication -> cell death & focal micro abscess
-invade phagocytic & non phagocytic cells
-escape from phagosome before maturation into phagolysosome
-cell to cell transfer w/o exposure to humoral defense mech

Question 3

Describe species of vet imp.

Answer 3

Question 4

Describe listeria monocytogenes.

Answer 4

‘Circling disease, silage disease’
-encephalitis most common form of listeriosis in ruminants (all age & sex)
-winter spring disease (seasonal) of feedlot or housed ruminants = less acidic pH of spoiled silage (moldy) enhance multiplication
-outbreak 10 d after feeding poor qual silage
-ingestion, inhalation, entry via oral/nasal mucosa

Question 5

Describe the clinical signs of circling/silage disease.

Answer 5

-anorexia, depression, disorientation
-dullness, turning in circle towards affected side
-unilat trigeminal & facial nerve paralysis
>drooping ear, muzzle, eyelid, strabismus, nystagmus, head pressing
-purulent unilat endopthalmitis

Question 6

Describe the diagnosis of circling/silage disease.

Answer 6

-differential diagnosis: ketosis, preg toxemia, BSE, thrombotic meningoencephalitis, rabies, lead poisoning, parasitic infection
-antemortem = silage qual, CS, season, incubation time
-lesion in brainstem

Question 7

Describe the T & P of circling/silage disease.

Answer 7

-early stage of septicemic listeriosis = pen
-neural listeriosis = amp & gentamicin
-no vaccine

Question 8

Describe the zoonosis & food borne disease.

Answer 8

-90% listeria inf from YOPI
-3rd cause of death from food poisoning
-1600 ppl US per yr
-survive pasteurization

Question 9

Describe the key bacterial characteristics of Erysipelothrix.

Answer 9

-gram pos rods (elongated & thin)
-facultative anaerobes
-non motile
-catalase (-), oxidase (-)
-in tonsils & intestine of many species
-50% healthy pigs have it in tonsillar tissues
-carrier pigs = excrete in feces & oronasal secretions
-resistant to harsh environmental conditions
-swine most imp reservoir
-septicemia, dermatopathy, arthritis, endocarditis depending on strain & IS

Question 10

Describe the virulence factors & pathogenesis of Erysipelothrix.

Answer 10

-pathogenicity = makes neuraminidase
>endothelial cell surface -> vascular damage -> thrombus
-diff stereotypes
-transmission by ingestion

Question 11

Describe the species of vet imp.

Answer 11

Question 12

Describe erysipelothrix rhusiopathiae.

Answer 12

‘Swine erysipelas, Diamond skin disease’
-acute = sudden death, fever, arthritis, sep from group, anorexia, skin lesion
-subacute = inappetence, fever, skin lesions
-chronic = arthritis, endocarditis, skin lesion
-most sus = pigs 3mo-1yr
-stress
-diamond shape lesion = pathognomic for swine erysipelas

Question 13

Describe diamond skin disease diagnosis, treatment & control.

Answer 13

1. Diagnosis
   -skin lesion
   -isolate the pathogen from skin or joints
   -PCR
2. Treatment
   -acute = isolate & treat w antimicrobials
   -resistance
   -cull chronic
3. Control
   -hygiene
   -vaccine for boars every 6MO & sows 3-4w before farrowing

Question 14

Describe erysipelas in turkeys.

Answer 14

-all age
-acute = septicemia, sudden death
-chronic = endocarditis & weight loss

Question 15

Describe non suppurative polyarthritis in lambs.

Answer 15

-enter thru umbilicus or castration wounds
-post dip lameness due to cellulitis & laminitis in older lambs

Question 16

Describe erysipeloid in humans (zoonotic).

Answer 16

-occupational hazard
-enter thru minor skin abrasion in contact w animals secretions
>cellulitis in fingers
>diffuse skin inf
>septicemia
-human erysipelas = inf skin disease by group A b-hemolytic streptococci (SELF RESOLVING)