Neurologic Diseases Of Ruminants

Question 1

Listeriosis

Answer 1

Gram positive rods - short rods
Facultatively anaerobic
Motile
Most common species causing disease in domestic speices

Question 2

Origin of listeria

Answer 2

Listeria monocytogenes
Soil, silage, sewage, decaying matter, GIT of various species
Present in animals & humans as asymptomatic enteric carriers & shed in feces

Question 3

Important sources of listeria

Answer 3

Human - food, soft cheese, seafood & meat
Domestic species - spoiled silage (pH >5.5)
(Can cause abortion)

Question 4

Route of infection - listeria

Answer 4

Ingestion
Direct entry through mucus membranes

Question 5

Ingestion of listeria

Answer 5

Usually = septicemia or “visceral form” = abortion

Question 6

Direct entry of listeria

Answer 6

Eyes, nose, oropharynx
Can spread along cranial nerves (esp trigeminal)
= “neural form” of diseas

Question 7

Virulence factors of listeria

Answer 7

Listeriolysin O (hemolysin)
Produce lysis of cells (RBC) and aid intracellular survival /transfer between cells

Question 8

Neural form of listeria

Answer 8

Circling disease
Common in sheep. Sporadic form of disease
Entry to CNS is retrograde, intra-axonal migration along trigeminal nerve or occasionally hematogenous
Infection = encephalitis w unilateral lesions localized to brainstem
Asymmetric disorder of cranial nerve function

Question 9

Clinical signs of circling disease

Answer 9

Anorexia, depression
Head tilt or pressing and/or circling (towards
affected side)
• Unilateral facial paresis/paralysis with
drooping ears, deviated muzzle, flaccid lip
and lowered eyelid (on affected side)
• Lack of menace reflex, (central) blindness,
and profuse, continuous salivation
• Terminal – unable to rise (recumbency),
involuntary running

Question 10

Visceral form of listeria

Answer 10

animals infected with L. monocytogenes may also get septicemia, with dissemination to various organs ü this form of the disease is the most frequent form seen in neonates and non-ruminant species;
may also get abortion (mostly in ruminants

Question 11

Diagnosing listeria

Answer 11

History, clinical signs, species
Asymmetric brainstem dysfunction with depression/
Obtain sample from lesions
Brain (brainstem), blood, aborted fetus, Ø Gram stain/Diff Quik
Should see gram + short rods; but may
not be present especially in chronic disease
enrichment for Listeria)

Culture aerobically (+/- cold Ø Other tests e.g. Histology (classical

Question 12

Antibiotics for listeria

Answer 12

Penicillin and oxytetracycline - treat quickly
Treatment is not effective in chronic cases
Trimethroprim/sulfonamides and rifampin combo therapy is used for dogs

Question 13

Management of listeria

Question 14

Vaccine for listeria

Question 15

Clostridium perfringens type D

Answer 15

normal flora in Large intestine - gut stasis migrate to SI = epsilon pro-toxin = active toxin = entry to blood
= enterotoxemia
- acute disease = pulpy kidney
- chronic disease = focal symmetrical encephalomalacia (FSE)

Question 16

Enterotoxemia

Answer 16

Acute disease - epsilon toxin = endothelial damage = vascular leakage and severe tissue damage
Aka pulpy kidney

Question 17

Chronic type D

Answer 17

Epsilon toxin causes endothelial damage = vascular leakage and tissue damage in lateral thalamus and cerbellar peduncles

Question 18

Histophilus somni

Answer 18

Gram negative rods - microaerophilic
Normal flora of mucosal membranes of cattle (genital and URT)
Environmental stressors
Spetic emboli lodging in CNS results in lesions of thrombus formation = thrombotic meningoencephaliitis

Question 19

Neuro disease in pigs

Question 20

Glasserella parasuis

Answer 20

Gram neg rods - Facultatively anaerobic
Normal flora of URT of pigs
(FPT or stressors = septicemia with localization in serous surfaces)

Question 21

Polyserositis

Answer 21

Glassers disease
Including meningitis (arthritis, pleuritic)
Lameness, pyrexia, anorexia & convulsions

Question 22

Strept suis

Answer 22

Gram positive cocci - Facultatively anaerobic
Asymptomatic carrier pigs have organisms in tonsillar tissues
Risk for invasion - over crowding and poor ventilation

Question 23

Septicemia and meningitis

Answer 23

Also arthritic and bronchopneumonia
Fevers, tremors, in coordination, convulsions, death