food animal infections of nervous system Flashcards
What viruses cause congenital malformation?
BVDV, blue tongue, akabane
What VIRUSES cause encephalitis?
Rabies
Cattle: bovine herpes virus 5, malignant catarrah fever,
Pigs: pseudorabies
Lentivirsues
DDx?
DDx: Border dz***
v. blue tongue v. akabane v. cache valley
Border Disease signalement? Pathogenesis? Syndromes (4)?
Newborn lambs- congenital infection
Syndromes:
1. early embryonic mortality
2. abortion & still birth (@ any point)
3. early in gestation –> lambs = persistently infection (PI)
4. after 85 days in gestation –> normal w/ antibodies
What does the Border Disease virus have tropisms for?
Lymphoid tissue, CNS - oligodendrocytes, Hair follicles (hair shaker)
Pathologic findings for Border Disease?
Infection during fetus CNS development –> neurologic or ocular degen.
- cerebellar hypoplasia
- hydranencephaly (loss of cerebral hemis)
- porencephaly (cysts in cerebral hemis)
Border disease clinical signs? (5)
tremors (hypomyelinogenesis)
ataxia (cerebral hypoplasia)
hairy birth coat
short, boxy stature
facial bone malformations
ocular abnormalities
Who gets infected in MCH? How is it shed?
Ovine-herpesvirus type 2
Infection by CARRIER domestic or wild sheep/got hosts –> susceptible hosts (CATTLE, BISON, FARMED DEER
Major shedding events = during lambing/kidding!
What virus do corneal edema (blue eyes) and multi-focal hemorrhage manifest in?
MCH
What causes Bovine Spongiform Encephalopathy (Mad Cow Disease)?
Abnormal prion protein
Hallmark lesion for TSE?
DDx?
DDx - rabies v. caprine arthritis encephalitis
Latter = a lentivirus - use serology to determine antibody presence! (lentivirus: infected for life, even if no clinical signs [majority of goats])
Where do lentiviruses replicate?T Type of infections?
replicate in macrophages
once infected, px is infected for life
What are the main findings on histo for caprine arthritis encephalitis
severe arthritis; SC granulomatous inflamm. w/ perivascular cuffs
DDx?
classical swine fever v. Atypical porcine pestivirus v. porcine herpes virus
Key trait about pestiviruses?
The persistently infected animal spreads the virus to others
Clinical signs of atypical porcine pestivirus?
congenital tremors in suckling / young pigs
Key pathologic finding of classical swine fever?
necrotizing tonsilitis
What disease in pigs is known as pseudorabies in other species?
Aujeszky’s Disease - a herpes disease (stress-induced)
Aujeszky’s Disease route of infection?
aerosol transmission
virus replicates in tonsils / oropharnyx –> spreads to regional LN –> latent in trigem gang –> stress
cardinal signs of food animal spinal cord infection (6)
- limb weakness / ataxia
- muscle atrophy / flaccidity (gray matter)
- increased or decreased limb reflexes
- loss of sensation
- recumbency
- ABNORMAL menace! (depressed, obtunded)
How are spinal cord infections in food animals diagnosed?
CSF analysis
3 most common congenital / hereditary spinal cord infections?
- Spastic paresis (elso heel), straight hock syndrome
- Periodic spasticity (stretches)
- Bovine progressive degenerative myelopathy (BPDME // Brown Swiss)
Spastic paresis signalment and clinical signs
young ruminants; stiff, asymmetric gait, bilateral but one limb more stiff/stretched than the other.
Periodic spasticity signalment and clinical signs
adult cattle; spastic extension, abduction of PLs during onset of walking
Bovine progressive degenerative myelopathy signalment and clinical signs
Onset of bilateral PL ataxia and dysmetria 5-8 months of age -> deficient proprioceptive responses, ataxia in all 4 limbs, progressive paraparesis. normal spinal reflexes and cranial nerve functions
5 most common spinal cord infections?
- Spinal epidural abscess (empyema)
- Tetanus
- Small ruminant lentiviruses
- Parelaphostrongylus
- Botulism
Spinal epidural abscess (empyema) signalement, pathogenesis, what it can lead to
Young ruminants
Iatrogenic (improperly prepared epidural injections) -> bacteria extends from the septic vertebral jt -> vertebral physis -> causes DISCOSPONDYLITIS -> can lead to fx (affects structure of the bone) or compress spinal cord via pressure
What are discospondylitis and osteomyelitis? Pathogenesis?
Disco = Inflammation of the intervertebral disc and adjacent vertebral bodies
Osteo = inflammation of the vertebra without concurrent disc infection
Calves with failure of passive transfer (IgG). hematogenous spread.
No tx, poor-to-guarded prognosis
Signalment of tetanus-infected animals?
Neonates via umbilical cord (1-4 weeks of age), post-partum in adult cattle (1-4 weeks), 1-4 weeks after castration, dehorning
What antibiotic class is given for tetanus? Prevetion?
Penicillin
Prevention = VACCINATION
Signalment of botulism-infected animals? How is it diagnosed?
Any age, any species. Dx = flaccid tongue / clinical signs; PCR on GI contents or feed
Treatment for botulism?
Anti-toxin; remove contaminated feed; Type B vaccine (EQUINES ONLY)
Caprine Arthritis Encephalomyelitis (CAE) signalment? Pathogenesis? Prognosis? Prevention?
GOATS
1-5 m/o kids** and adults (via colostrum** or close contact)
POOR PROGNOSIS -> death within weeks-to-months
PREVENTION: test biannually or annually and cull positive animals; heat milk or use replacement
Examination findings of CAE-positive goat? Dx?
BAR, no fever, normal appetite
Neuro: UNILATERAL paraparesis and ataxia -> asymmetric tetraparesis and ataxia
Dx: CSF fluid = hyperproteinemia & monocytosis
Ovine Progressive Pneumonia (OPP / Maedi Visna) signalement / clinical signs? Prevention?
Sheep, usually older than 2 years. Progressive ataxia, flock mates with respiratory signs, “hard bag” arthritis
Hosts of the meningeal worm (parelaphostrongylus tenius)?
Natural = white-tailed deer
Intermediate = snails and slugs
Aberrant = camelids & ruminants –> CNS SIGNS***
Clinical signs of the meningeal worm? Why is the prognosis guarded?
sudden / rapid progression of unilateral or bilateral, asymmetric paraparesis or tetraparesis, ataxia
Guarded prognosis due to damage by the migrating worm!
Treatment for meningeal worm?
Ivermectin + Fenbendazole; anti-inflammatory; omeprazole or pantoprazole
What are 2 of the most common types of nutritional / toxic spinal cord infections in FA?
Enzootic ataxia (Swayback) and delayed organophosphate toxicity
Pathogenesis of enzootic ataxia and the two forms
dietary copper deficiency of mother -> in-utero copper deficiency of kids & lambs; congenital and delayed (2 weeks to 4 months old)
Clinical signs of enzootic ataxia?
progressive weakness and ataxia (caudal to cranial) -> para-to-tetraparesis; flaccid paralysis
Clinical signs of delayed organophosphate toxicity?
SLUD - d+, loss of bladder function; DELAYED NEURO SIGNS (8-90 DAYS POST EXPOSURE); weakness
Clinical signs of peripheral nerve compression
limb weakness, ataxia, muscle atrophy, reduced skin sensation, reduced limb reflexes
What nerves are vulnerable to compression / paralysis during calving?
Sciatic*, obturator, femoral, peroneal
What does this cow exhibit?
Knuckling, weakness due to calving paralysis
Tx plan for compression neuropathy (calving paralysis)
- Dexamethasone IV or IM ASAP
- Move to comfortable area + supportive care
- Turn sides at least 4x/day (avoid secondary ischemic necrosis)
- Euthanasia if cow does not remain sternal / lays in lateral recumbency
What neoplasia can bovine leukemia virus (BLV) cause? Clinical signs? Tx?
Epidural Lymphosarcoma (LSA). Progressive asymmetric ataxia and paraparesis. Tx = EUTHANASIA!
What areas of the body do LSA have an affinity for?
Right atrium of the heart, the uterus, the spine, the abomasum, the lymph nodes
Cardinal signs of neuromuscular disease
flaccid tetraparesis, mydriasis, dysphagia, bloat, recumbency
Cardinal signs of neurological disease:
blindness, seizures, mental depression, dementia
How does thiamine (VitB) deficiency manifest in ruminants? Signalment?
thiamine deficiency (VitB) -> cerebral edema -> head-pressing, dull, ataxia, opisthotonos, seizures.
SUCKLING CALVES & KIDS; feedlot weanlings
