Listeria

Gram-Positive Asporogenous Aerobic Rods

soil, silage, sewage effluent, stream water

Listeria is a pathogen, common to domestic animals found in the _____, _______, _______ and ______

facultative

Listeria is a _______ intracellular parasites

in ruminants

Where does Listeria infection frequently seen?

1. L. monocytogenes

2. L. innocua

3. L. welshimeri

4. L. seeligeri

5. L. ivanorii

6. L. grayi

Species associated with animal infections

• Gram-positive rods

• non-acid fast which show slight clubbing (Diphtheroid in appearance)

• Do not produce capsules and spores

• motile by means of peritrichous flagella

• The cell wall contains meso-diamo-pimelic acid

Morphology, Staining features and cellular composition

• Facultative anaerobes that tolerate heat

• Grows at 40 to 45 C under reduced O2 and increased CO2

• Grows at a pH of 5.5 to 9.6

• Hemolytic on blood agar (Beta hemolytic)

Growth Characteristics

Soil, Sewage effluent, silage, stream water

Reservoir of Infection

1. Soil contamination

2. Ingestion of contaminated feeds

Transmission

1. Listeriosis in ruminants

2. Primary Listeric septicemia

3. Votheysveiki or “Silage disease”

4. Mengioencephalitis or “Circling disease”

Diseases associated with Listeria species

Listeria monocytogenes

• Septicemic infection marked by a tendency of the infected animal to circle in one direction or move in circles

• damage of the neural surfaces, sheath and dental terminals of the trigeminal nerve

• Head pressing (sheep), unilateral facial paralysis and chewing motions

• Abortion at the second trimester of pregnancy (Cattle), latter stage of pregnancy (Sheep and goats)

  • Listeria multiplies and kills the fetus

Etiologic agent and Clinical Signs of Listeriosis of Ruminants

1. Primary listeric septicemia

2. Votheysveiki or “Silage disease”

3. Meningoencephalitis or “Circling Disease”

Forms of Listeriosis

• Infects young ruminants and monogastric animals

• septicemia

Descriptions about of Primary Listeric septicemia

Associated with Listeria-infected silage

Descriptions about of Votheysveiki or “Silage disease”

• encephalitic form

• Ocular or nasal routes of entry

• involvement of the neural sheaths of peripheral nerve endings (trigeminal nerve)

• CNS involvement (CSF cloudiness and congestion of meninges)

Descriptions about of Meningoencephalitis or Circling Disease

• Heat tolerance

• Hemolysins

• Immuno-suppressive envelope component

• Glutamic acid decarboxylase

• Phospholipase and lipase

• Listeriolysin O

• Ivanolysin-thiol-activated cytolysin

• Lipolysins

Virulence Factors

Heat tolerance

Favors survival at pasteurization temperature

immuno-suppressive envelope component

diminishes host cell-mediated immuno-competence

Glutamic acid decarboxylase

enhances pathogenesis of encephalitic listeriosis

Phospholipase and lipase

mediate membrane lysis

Listeriolysin O

Facilitates survival of Listeria in cells by lyzing phagolysosome and ferritin vesicles

Lipolysins

Act on glutamic acid (an excitatory neurotransmitter) and on end-products of gamma-aminobutyric acid to mediate convulsions

1. spinal fluid

2. blood

3. brain tissue

4. spleen

5. CSF

6. aborted placenta

7. fetus

Laboratory diagnosis samples

1. Isolation and cultivation of the pathogen

2. Pathogenicity test

3. PCR that use primers for Listeria

Agent of Identification

1. sheep blood agar

2. Lithium chloride phenyl ethanol

3. moxalactam medium

4. oxgall medium

5. PALCAM Listeria selective media

Preferred Media

mouse inoculation

Pathogenicity test how?

1. Ampicillin and Benzyl Penicillin G (Intrathecal administration)

2. Sulfonamides and Tetracycline

3. Penicillin and Gentamycin combination

Treatment

• elimination of feed-infected silage

• Minimize stress

Prevention and control