general Flashcards
1
Q
Where are the best seen CNS lesions of malignant catarrhal ovine fever?
A
Arteries of the rete mirabile
Malignant catarrhal fever (MCF) is a highly fatal lymphoproliferative
2
Q
Which virus(es) is(are) implied in malignant catarrhal fever (MCF) in cattle?
A
Alcelaphine herpesvirus type 1 (AlHV-1)
Ovine herpesvirus type 2 (OvHV-2)
3
Q
What are the difference between goat and sheep with lentivirus infection?
A
Goat (CAEV)
Young kids (1-6 months)
Leukoencephalomyelitis with ascending paresis (short shoppy gait initially)
Sheep (MVV/OPPV)
Adult
Brain form (head tilt & circling toward the affected lateral ventricle ± hindlimb hypermetric ataxia) or spinal form
Irreversible and progressive disease, without treatment in both species
Now believed that ovine & caprine lentivirus form one large group of viruses with strong evidence for cross-species transmission MVV/OPPV and CAEV are taxonomically combined together as the ovine/caprine lentivirus group
4
Q
Serology conversion usually occurs within .. with lentivirus infection
A
2-12 weeks (up to 8 months)
The clinical condition is slowly progressive and results in paralysis and death over the course of several months.
5
Q
Positive serologic or PCR test is sufficient for antemortem diagnosis of lentivirus myeloencephalitis in small ruminants?
A
False
High prevalence -> false positive
Postmortem diagnosis is based on demonstration of the characteristic lymphocytic infiltration of the CNS. Virus isolation or additional viral identification is rarely performed.
6
Q
What is the cause of thrombotic meningoencephalitis in cattle?
A
Histophilus somni
7
Q
What is the main infectious agent for otitis media in pigs?
A
Streptococcus suis
8
Q
At which age is menace response present in foals and calves?
A
Several days
9
Q
What is the most common cause of facial paralysis in cattle?
A
Otitis media
10
Q
What is the main risk factors for OMI in ruminants?
A
Presence of a coincidental respiratory infection
Many studies document bacterial OM in conjunction with or after respiratory disease, with the same causative pathogens isolated.
11
Q
Hypovitaminosis A in calves is associated with which abnormality?
A
Dural fibrosis causing hydrocephaly
12
Q
Ptosis can be caused by
A
Frontalis
levator palpebral superioris muscles
Oculomotor nerve
13
Q
Which parts of the neurologic system are visible in large animals?
A
Glossopharyngeal nerve, retina, optic disc, optic nerve
14
Q
Central blindness and opisthotonos are common signs of
A
Polioencephalomalacia
15
Q
Progressive ataxia of Charolais cattle is due to a defect in:
A
Oligodendrocytes
16
Q
Which bacteria contain thiaminase?
A
Clostridium thiaminolyticum
Bacillus thiaminolyticus
17
Q
What is the disease, the gene and the breed associated with congenital hyperammonaemia in cattle?
A
Citrullinemia
Arginosuccinate synthetase (ASS1)
Holstein-Friesian
18
Q
What is the gene associated with progressive ataxia of Charolais cattle? What pathological changes are found?
A
KIF1C
Leukoencephalomyelopathy: demyelination of the brain and spinal cord; and production of multifocal, acellular, pale, eosinophilic plaques prominent in the cerebellar peduncles and medulla oblongata
19
Q
What are the 6 entries for pathogens in the CNS?
A
Hematogenous (e.g. thromboemboli)
Penetration of BBB within mononuclear cells (mostly viruses)
Circumventricular organs (e.g. pituitary abscess)
Axons of nerves
CSF (e.g. bacterial)
Direct lesion (e.g. fracture)
20
Q
What is the most frequent virus implied in bovine herpesvirus encephalitis?
A
BHV-5
Although BoHV-1 rarely causes encephalitis, BoHV-5 demonstrates marked neurotropism and the ability to cause severe and often fatal encephalitis.
Encephalitis caused by BoHV-1 is uncommon compared with the respiratory (infectious bovine rhinotracheitis [IBR]) and genital (IPV and IBP) syndromes.
BHV-5 induced neurologic signs include muscle trembling, circling, ptyalism, jaw chomping, tongue protrusion, head pressing, and ataxia. Absence of blindness.
21
Q
What are the 2 routes involved in the dissemination of BHV-5 in the CNS?
A
Trigeminal and olfactory pathways
After colonization of the upper respiratory tract, infection of the CNS occurs through neurotropic spread within sensory neurons originating in the nasopharynx.
22
Q
What is the gene associated with bovine progressive degenerative myeloencephalopathy in Brown Swiss Calves?
A
PNPLA8
Weaver syndrome
23
Q
In which specie and breed have been described the RELN mutation, similarly to the White Swiss Shepherd?
A
Spanish Churra milking sheep
24
Q
What are the 2 routes of transmission of Bornavirus to the CNS?
A
Nasal epithelium – olfactory nerve
Pharyngeal epithelium – trigeminal nerve
25
Give 3 common causes for seizures in cattle
HypoMg
HypoCa
Cerebrocortical necrosis
Inflammatory disease
Lead intoxication
26
Which histopathological finding is pathognomonic to borna disease?
Intranuclear eosinophilic inclusion bodies (Joest-Degen bodies)
27
DDx forebrain
Anomalous: congenital malformation
Metabolic: polioencephalomalacia, nervous ketosis, hepatic encephalopathy, hypoglycemia
Toxic: lead, organophosphates, urea/NH3, salt toxicity/water deprivation
Inflammatory:
Bacterial: listeriosis, abscess
Viral: rabies, BHV-5, BHV-1, pseudorabies, malignant catarrhal fever, BSE
(camelid: P tenuis, EEE, WNV, EHV-1)
Traumatic
28
What are the 3 most common causes of cerebral disease in calves?
**Polioencephalomalacia**:
- Thiamine deficiency
- High-sulfur diet
- Low-roughage diet
- High doses of amprolium
- Cobalt-deficient diet
- Molasses-urea diet
- Ingestion of various toxic plants
**Bacterial meningitis** (usually in calves less than 2-3 weeks of age)
**Hypernatremia** (salt poisoning)
29
Cause and age for meningitis in calves?
Cause: sequelae to **septicemia**: E. coli is the most common pathogen
Others: Salmonella, Campylobacter, Klebsiella, Staphylococcus
Age: **before 30 days** of age
Colonization of GI tract before establishment of normal flora
Bacterial colonization of another site such as umbilicus (omphalitis)
30
Which pathogen cause pseudorabies?
Suid herpesvirus 1
31
Congenital abnormalities are seen during in utero infection by bovine diarrhea virus between ____ and ____ days of gestation.
125
180
32
What is the mechanism of maple syrup urine disease (MSUD)?
BCKDHA (AR) -> **Branched-chain ketoacid dehydrogenase deficiency**
Storage disease with elevated concentrations of branched chain alpha-keto acids and their precursors, the branched chain amino acids, valine, leucine and isoleucinein in blood and tissues
33
What are the lysosomal storage diseases described in ruminants and the breed concerned?
**Alpha-mannosidosis** in Angus, Murray Grey & Galloway: Nonlipid vacuolation of cells in the cerebrum, cerebellum, and spinal nerves
**Beta-mannosidosis** in Salers: Vacuolation of the Purkinje cells and decreased myelination of the cerebellum
**Maple syrup urine disease** in poll Herefords & poll shorthorns
**GM1 gangliosidosis** in Friesian, sheep
Pompe disease (GSD 2) in shorthorn & Brahman
**GSD 5** in Charolais
Muscles
**Citrullinemia** in Holstein-Friesians
34
What is the gene associated with hemifacial microsomia? In which breed?
**LAMB1** gene (AR), laminin subunit beta 1
**Romagnola** calf
Signs: microtia of the left ear, anotia of the right ear, asymmetry of the face, and deafness.
MRI: agenesis of the right pinna and both tympanic bullae, asymmetry of the temporal bones and temporomandibular joints, and right pontine meningocele.
BAER: impaired auditory capacity
Histo: **agenesis and hypoplasia of the right and the left external ear**, respectively. No histological abnormalities were detected in the inner ears.
35
What are the typical neuropathologic lesions of bovine spongiform encephalopathy?
Bilaterally symmetric **intracytoplasmic vacuolation** of brainstem gray matter and neurons
36
Which allele(s) confer resistance to scrapie? Which one(s) confer susceptibility?
Resistance: **ARR**
Note: scrapie is still detected in some sheep that are ARR homozygous
Susceptibility: **AHQ, ARH, ARQ, and VRQ**
Resistance to scrapie is linked to polymorphisms at codons A136V, R154H, and R171Q of the prion protein gene.
37
Which clinical and most useful sign is associated with scrapie?
Response to **scratching or light pressure over the withers** causing sheep to raise their head, point their muzzle dorsally, elevate their upper lip and lick their lips and make chewing movements
Clinically, scrapie is a slowly progressive debilitating disease with progression taking from 2 months to as long as a year.
With progression, clinical signs include **severe weight loss, poor appetite, pruritis and wool loss, and neurologic signs.**
Neurologic signs can include **altered mentation, hyperesthesia, head bob, muscle fasciculations, hypermetria, dysphonia, dysphagia, blindness, and uncoordinated muscular movements**.
38
Scrapie is only transmitted horizontally: true or false?
False
**Horizontal and vertical transmission** are reported with scrapie; hence, the prolonged latent period is critically important because ewe’s infected with scrapie will have ample opportunity to transmit the disease to their offspring, and lambs born to other ewes before they themselves manifest with clinical disease.
39
Which is most frequent clinical profile with BSE?
The most frequent clinical profile for a cow with BSE is **apprehension or nervousness combined with hyperesthesia and ataxia** observed over a 15-day period.
A small proportion of animals may show true “mad cow” syndrome manifest by **aggression and manic behavior**.
40
Among calves that have cerebellar hypoplasia and atrophy, what is the proportion of those that have also optic nerve hypoplasia and atrophy?
25%
41
Cerebellar hypoplasia is caused by in-utero infection of bovine viral diarrhea virus at
**100-200 days** of gestation
Congenital abnormalities of BVDV (both **cerebellar hypoplasia and ocular abnormalities**) occur following infection of the cow at **125 to 180 days** in gestation. Administration of a modified live BVDV vaccine induced teratogenesis during 90 to 118 days’ gestation
42
What are the 4 main causes of cerebellar hypoplasia in ruminants?
**Inherited**: Hereford, Shorthorn, Angus, Holstein, Guernsey, Ayrshire (recessive)
**BVD** (Pestivirus) in cattle (100-200 d gestation)
**Border disease** (Pestivirus) in sheep
**Bluetongue** (Orbivirus) in cattle & sheep
43
What are the main malformations associated with Schmallenberg virus? In which species?
Malformations:
**Porencephaly to hydranencephaly**
**Cerebellar dysplasia** (loss of **PC** and depletion of **granular** cell layer)
**Brainstem** dysplasia
**Spinal cord** dysplasia
**Brachygnathia** inferior
**Arthrogryposis**
**Vertebral column** malformations
Species: calves (45%), **lambs** (95%), kids
44
common infectious agent of suppurative otitis media-interna in ruminants kept under intensive stocking conditions?
Mycoplasma spp
45
What are the 2 teratogenic viruses transmitted by Culicoides spp.?
Schmallenberg virus
Bluetongue virus
46
Which cattle breeds are associated with familial cerebellar hypoplasia?
Hereford
Shorthorn
Ayrshire
47
Which cattle breeds are associated with cerebellar abiotrophy?
Angus
Poll Hereford
(other breeds: Ayrshires, Charolais, shorthorns, Limousin)
48
Which plant can induce cerebellar diseases in cattle and goats? Which pathological findings?
**Solanum** spp.
In affected goats, histopathologic lesions were observed throughout the cerebellum consistent with a storage disease; however, the mechanism of the toxicity is unknown. Lesions observed histologically in Solanum toxicities are of **wallerian-type degeneration** of the cerebellum alone, with loss of **Purkinje cells**.
49
Why lead poisoning is more frequent in young animals than adult?
Young absorb up to 50% of the lead ingested whereas, older animals absorb 1-3%.
50
Mechanism of action of strychnine?
Inhibit action of glycine in the spinal cord
51
Which bacteria produce enterotoxemia in cattle? Pig?
**Clostridium perfringens type D** (𝜀/epsilon toxin): sudden death (30-90 minutes) in lambs, kids, and calves, typically in growing animals (the toxin targets the brain, causing liquefactive necrosis, edema, and hemorrhage)
**E. coli producing angiotoxin** = Shigella (Shiga)-like toxin: brain edema (leakage of protein rich fluid) and symmetrical lesions with vascular hypertrophism, necrosis and hemorragic lesions causing fibrinoid vascular necrosis
52
Which clinical and pathological findings are associated with C. perfringes type D epsilon intoxination?
*Clinical signs*
Sudden death of well-nourished, growing animals
**Abdominal pain, ataxia, trembling, and convulsions** may be seen, with **death occurring in 30 to 90 minutes**
*Pathologic findings*
**Glycosuria in lambs**
**Encephalomalacia**
Large swollen kidneys (**pulpy kidney**) due to rapid decomposition
Minimal GI lesions in sheep
**Catarrhal, necrotic enterocolitis in goats**
53
What is the mechanism for enterotoxemic encephalopathy in cattle?
C. Perfringes type D: production of **epsilon toxin** in the form of a prototoxin with minimal biologic activity: activation by **protease or trypsin and chymotrypsin**: > 1000 times more toxic than the prototoxin
Action on receptor for epsilon toxin on **vascular endothelial cells** -> cause **degeneration of tight junctions** -> influx of protein and fluid -> swelling and rupture of perivascular astrocytes -> **elevating ICP**
54
What is the treatment for lead toxicosis in cattle?
**Calcium versenate** (CaEDTA): to chelate lead in bones: Pb binds irreversibly to erythrocytes proteins, When erythrocyte is removed from circulation, most of the lead is deposited in bone as a triphosphate salt
**Thiamine**: significantly reduce clinical signs
**Magnesium laxative**: reduce absorption of insoluble lead salts
55
What are the toxins produced by cyanobacteria, their mechanism of action, and the known antidote?
**Anatoxin-a**: depolarizes nicotinic receptors -> rapid death by respiratory paralysis
**Anatoxin-as** (Anabaena spp.): blockade of AChE (similar to organophosphate poisoning)
Antidote: **atropine**, but only for anatoxin-as (muscarinic antagonist)
56
What is the main physiolopathologic difference between enzootic ataxia and swayback?
Swayback: congenital copper deficiency
Enzootic ataxia: postnatal copper deficiency
57
Which toxicosis can cause alpha-mannosidosis? By which mechanism?
**Swainsonine** poisoning (**locoweed**)
Swainsonine inhibits lysosomal enzymes (**alpha-D-mannosidase and Golgi mannosidase II**), resulting in accumulation of their substrates -> lysosomal disease
58
Most common bacteria responsible for cerebral abcess in ruminants
**Trueperella pyogenes**
(= *Actinomyces* pyogenes)
Other bacterial species commonly isolated include Staphylococcus sp., Streptococcus sp., Fusobacterium necrophorum, and C pseudotuberculosis.
59
Give 2 explanations for the preferential location of pituitary gland for abscess in ruminants.
Rete mirabile
Absence of BBB
60
Which non-neurological sign is frequently (>50%) seen with pituitary abscess due to compression of the hypothalamus?
Bradycardia
61
What is the most common risk factor for pituitary abscess?
Use of nose flaps for weaning calves or the placement of nose rings
62
About 30% of cattle with pituitary abscess can survive with adequate treatment: true or false?
False
Pituitary abscess syndrome is consistently fatal. Therefore, treatment is unrewarding and typically not recommended.
63
What are the most common clinical signs associated with pituitary abscess?
Brainstem dysfunction associated with cranial nerve deficits:
Depression -> most common sign
Typically asymmetrical
CN II: blindness
CN III: strabismus, PLR
CN V: jaw hypotonia, decreased facial sensation
CN VII: facial paralysis
CN VIII: head tilt, nystagmus
CN IX/X: dysphagia
CN XII: tongue hypotonia
Recumbency, opisthotonus and convulsions may be seen in terminal stages of the disease.
64
What are the causes of thiamine deficiency in cattle?
Diet: disruption of the normal ruminal microbial population with decreased thiamine producing bacteria
Bacterial thiaminase (**rumen-acidifying high-energy diet** -> thiaminase type II)
Thiaminase containing plants (**bracken fern, horsetail**)
Thiamine antimetabolites (**amprolium** which is a coccidiostatic)
65
Which CN is often affected in polioencephalomalacia (thiamine deficiency) in cattle?
CN IV causing dorsomedial strabismus
66
DDx polioencephalomalacia (cerebrocortical necrosis) in ruminants
**Thiamine** deficiency
**Sulfur** toxicity (High dietary sulfur increased metabolic demand for thiamine )
**Lead** toxicity
**pyrophosphate**: high thiamine demand will lead to thiamine deficiency
**Salt** intoxication/water deprivation
**Selenium** toxicity
Cerebral **anoxia**
**Mercury** toxicity
**Copper deficiency** in lambs
**Molasses and urea** diet
**Amprolium**
67
What is the difference between calves and adult cattle in the metabolism of thiamine?
Absorption via food vs. thiamine-producing bacteria in the rumen
68
What are the 3 locations of degenerative lesions in thiamin deficiency?
Neocortex
Lateral geniculate nuclei
Caudal colliculi
69
What are the 3 plants that contain thiaminase?
Bracken fern
Horsetail
Nardoo fern
They contain thiaminase similar to thiaminase type I.
70
Listeriosis infects the CNS by
retrograde axonal transport
71
What is the difference between cattle and small ruminant in CSF evaluation in case of listeriosis?
Cattle: mononuclear pleocytosis
Small ruminant: often neutrophilic
72
What are the 4 CN most commonly involved in listeriosis? The less common?
Most common: V > VII, VIII > XII
Less common: VI, IX, X
73
Which test can be used to predict poor prognosis during listeriosis?
Creatine phosphokinase level in CSF (studied in sheep)
74
Who has the better prognosis in encephalitic listeriosis, cattle or small ruminants?
Cattle (70% survival) > Small ruminants (26%)
Very acute in SR
(death in 2-4 days in SR vs. 2 weeks in cattle)
75
What are the factors associated with survival in goats with listeriosis?
1/ **Females**: male goats were 14 times more likely to be a nonsurvivor compared to females despite being presented with similar history, clinical signs, and treatments.
2/ **Circling**: animals presented with circling or a history of circling were 6.24 times more likely to be a survivor than a non-survivor.
Other risk factors evaluated were not significantly associated with outcomes (duration, antimicrobial, anti-inflammatory, CSF)
76
What are the 2 most common Listeria monocytogenes serotypes implied? Which one is the most implied in zoonotic transmission?
Serotypes 1/2a
Serotype 4b most often responsible for infections in humans
77
What is the gene/breed associated with spinal dysmyelination ?
**SPAST** (CFA 11, AR)
Congenital recumbency with limb extension, moderate opisthotonos, body tremors
**Brown Swiss Cattle**
78
DDx spinal cord
Degenerative: **Brown Swiss** myelopathy (NMD/SMA & weaver), **Charolais** leukodystrophy
Metabolic-toxic: **enzootic ataxia** (goats), **organophosphate** toxicity, (hepatic)
Neoplasia: **lymphoma** (extradural)
Inflammatory: **discospondylitis, vertebral abscess, CAEV, rabies, Hypoderma bovis, P tenuis**
Traumatic: trauma (risk of fractures in young), (camelid: vertebral malformation)
Vascular: **FCEM**
79
Spinal lymphoma is more prevalent in small ruminant than in cattle: true or false? Why?
False
Because of Bovine Leukemia Virus
80
What are the causes of nutritionnal myelopathy in pigs?
**Copper deficiency**
Rapidly progressive PL paresis/ataxia in 3.5-6 mo.
Axonal degeneration
**Overdose of arsanilic acid**
Progressive PL ± TL paresis/ataxia
Axonal and myelin degeneration
81
What neuropathological findings are associated with water deprivation in pigs?
Polioencephalomalacia and eosinophils cell infiltrates
82
What is caused by selenium toxicity in pigs?
Acute **poliomyelomalacia** particularly in **ventral gray horn at the cervicothoracic and lumbosacral intumescence** + lesion in several brain stem nuclei (**cuneatus, gracilis, facial, trigeminal, reticular**)
83
What is the best diagnostic test for selenium toxicity in pigs?
Selenium concentration in the **liver**
(better than blood)
84
What is the preferential location for lymphosarcoma in cattle?
Lymphosarcoma tumors tend to be **extradural** in nature, causing compression of the spinal cord.
More than half of the cases reported in a recent study affected the **lumbar, sacral, and cauda equina** regions, leading to clinical signs of hindend ataxia and/or weakness.
85
What is the main risk factor for development of lymphosarcoma in cattle?
Bovine leukemia virus
Oncogenic deltaretrovirus that infects lymphocytes
86
What is the most common neoplasia of the bovine spinal cord?
Lymphosarcoma
87
Which parasites can induce spinal cord injury due to parasitic migration? Where are they located?
*Cattle:*
**Hypoderma bovis**
Extradural, in epidural fat, maj LS
*Other ruminants:*
**Parelaphostrongylus tenuis** or **Elaphostrongylus cervi**
Intraspinal (dorsal gray column)
*horse*
Halicocephalus gingivalis
88
Enzootic ataxia
1/ is caused by
2/ histopathologic lesion
3/ can be caused by high
1/Caused by **copper deficiency**
2/ **demyelination** in young lambs
3/**High molybdenum or sulfur** can interfere with absorption of copper
89
Which nutritional deficiency can induce spinal cord disease in kids and lambs? What are pathological findings?
Copper deficiency during the prenatal or immediate postnatal period
Enzootic ataxia (postnatal) or swayback (prenatal)
Animals are generally affected between birth and 4 months of age.
**Loss of myelin** in the spinal cord
Wallerian degeneration
Lesions may also be present in the cerebrum and cerebellum.
90
How to diagnose copper deficiency?
Low liver copper levels
91
Treatment of enzootic ataxia with copper is ineffective: true or false?
True
Because of impaired fetal development
92
Mechanism of organophosphate and carbamate toxicosis?
Block acetylcholinesterase
irreversible bond = organophosphate
reversible = carbamate
-> cholinergic crisis
93
Give 5 infectious agents that spread into nerves in large animals.
Bovine herpes virus 5
Listeriosis
Pseudorabies
Rabies
Bornavirus
94
Which mutation cause myotonia congenita in goats (fainting goat)?
+ transmission
CLCN1 skeletal muscle chloride channel – autosomal dominant with incomplete penetrance
95
Horner’s syndrome in cattle is characterized by
Miosis, ptosis, enophthalmos, anhidrosis
96
Hypocalcemia in cattle manifests:
Weakness, cold nose, cold ears, cold extremities, can progress to recumbence
97
What happens with the membrane potential in hypocalcemia?
Low Ca2+ => **facilitate sodium transport**, as the normal inhibition by Ca2+ of sodium movement through voltage-gated sodium channels is lost => increase excitability of excitable cells => discharge spontaneously => **tetanic muscle contraction**.
98
What are the 2 forms of bovine spastic paresis?
Early: **< 8 months**
Late: **2-6 yo**
Progressive **hyperextension of hindlimbs** and **contraction of Achilles tendon** caused by persistent spasms of certain muscles
99
Bovine spastic paresis is associated with reversible tonic and clonic muscular cramps: true or false?
False
It is bovine spastic syndrome
100
Bovine spastic syndrome has only symptomatic treatment: true or false?
False
Surgical treatment is possible
101
Where is the most common location with an hypoderma bovis infection in cattle?
Lumbosacral extradural spinal cord epidural fat
102
What are the 3 phases of clinical signs in hypocalcemia?
Phase 1: hyper excitability, **tetany**, hyperaesthesia, tachycardia
Phase 2: non-ambulatory in sternal recumbency with **reduced muscle tone**; head and neck turned towards the flank
Phase 3: **lateral recumbency**, progressively reduced mental state, tympany, death within hours
103
What happens with the membrane potential in hypomagnesemia?
Low Mg2+
the **normal inhibition of Ca2+ movement through voltage-gated Ca2+ channels dissipates**, so neurotransmission increases
particularly prominent at the neuromuscular junction
Results in **tetany and muscle spasms.**
104
Name 4 causes for tetany in large animals
**Tetanus**
**Strychnin**e toxication
**Hypocalcemia**
Inherited **congenital** tetany in polled **Hereford** calves, present at birth (Australia)
Presumptive inherited tetany as **myoclonus in Peruvian Pasaos**
105
Which gene is implicated in the Hereford calves with congenital tetany and myoclonia?
GLRA1
glycine receptor, subunit alpha1
106
What are the most common BoNT in ruminants?
B, C, D
107
What is the main route for botulism in ruminants?
**Ingestion of the toxin**
Botulinum toxin is ingested as a prototoxin that requires activation by endogenous proteases.
The route of infection is in contrast to tetanus, in which spores contaminate a wound, establish an anaerobic environment, and then begin to produce toxin. In cattle, conditions such as **phosphorus deficiency may cause pica** and result in cattle chewing on the carcasses of dead animals that contain BoNT.
108
What is the most frequent cause of the hypokaliemic myopathy in cattle?
Iatrogenic with use of **mineralocorticoid** drug for treatment of ketosis and clostridial mastitis
109
What are the breeds and the mutation for malignant hyperthermia in pigs?
Landrace, Pietrain
RYR-1 (ryanodine receptor)
110
Which nerve is the most commonly affected following dystocia in heifer?
**Sciatic nerve** (peroneal)
Obturator nerve is most commonly damaged secondary to compression following a prolonged dystocia; however, obturator nerve damage is less common than sciatic nerve damage following a dystocia.
Damage to the peroneal nerve following prolonged dystocia can result in the calving paralysis syndrome seen most commonly in first calf heifers.
111
sensitivity of CSF to diagnose lymphocarcoma
19%
112
radial nerve lesion
radial nerve : **extensor of elbow, carpus and digit + flexor of shoulder**
> unable to bear weight or dragging the affected forelimb, with a dropped elbow and partially flexed carpus and fetlock.
distal damage to the radial nerve, the triceps muscle may still be functional
analgesia of the dorsal surface of the foot.
causes: **prolonged recumbency** leading to a myopathy-compartmentalization syndrome, getting a forelimb trapped, excessive force placed on the distal neck and shoulder in a head catch, or falling on a hard, slick surface, **humeral fracture**, olecranon fracture, and **septic arthritis of the elbow joint**.
113
suprascapular nerve lesion
C6-C7, innervating the **supraspinatus**
and **infraspinatus** muscles.
extension and lateral support of the shoulder joint.
114
most common periferal nerve injury in cattle
**sciatic** (L6-S2) extensors of the hip and hock and flexors of the stifle, ext + flex fetlock
**peroneal** nerve following prolonged dystocia can result in the **calving paralysis** syndrome seen most commonly in first calf heifers. Other causes of sciatic nerve dysfunction include **injection** site abscesses or direct damage to the nerve during an intramuscular injection.
115
obturateur nerve injury
**L4-L6**, adduction of the PL
commonly damaged secondary to compression following a prolonged **dystocia**; less common than sciatic nerve damage, cattle slipping and abducting their hind limbs.
Animals should be able to walk and bear weight normally once standing.
116
femoral nerve lesion
**L4-L6**, **extension of the stifle and flexion of the hip**.
most commonly in **calves following forced extraction**
**cannot support the affected limb** because of a lack of extensor tone and take on a characteristic crouched posture if the injury is bilateral. Atrophy of the quadriceps femoris muscle may be noted 7 to 10 days after injury and patellar luxation may follow.
117
forms of CAEV and maedi/visna infections
CAEV
adult goat: chronic polyarthritis, bilateral mastitis, interst pneumonia, chronic wasting
kids 1-6m : **leucoencephalomyelitis**
Maedi/visna
kids: **paresis**
adult sheep: **brain (circling) or SC** (knuckling 1HL)
118
seroprevalence CEAV
widespread (seroprev >65%)
Canada, Norway, France, US
119
retrovirus in small rmnt
% developping disease
where is replication?
Caprine Arthritis and Encephalitis
Ovine progressive pneumonia and maedi-visna in North America and Europe, respectively
**30% dev disease**
replication in **monocytes** (vs lympho in other retrov), proviral DNA in monocyte for life but lymphoproliferative lesion **do not cause immunosuppression**
humoral + cell mediated response but do not confer immunity
120
gene confering sensibility to retrovirus in small rumnt
specif transmebran protein **TMEM154** (3x more likely)
121
transmission lentivirus in small rmnt + favorisant factor
ingestion of infected colostrum and/or milk, or through inhalation of respiratory secretions
factor: lenght exposure, animal density, housing type
122
symptoms of listeria infection
neurologic (sporadic, higher morbidity and mortality in small rmnt): multifocal **assymetric BS**, diffuse meningoencephalitis, myelitis
caudal BS, **cerebellar peduncle, SC**
CN **V - XII** usually dysfunctional
ocular: **keratoconjonct + uveitis** +/- hypopyos
**septicemia**: neonat death
sporadic **late abortion**
**mammitis
diarrhea**
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listeria characteristics, maj serotype
**gram +**, non spore forming, facult anaerobic
persistant years in env, can replicate in refrigerated temp
inhib pH < 5.6
**facult intracellular, can replicate in monocytes/macrophages**
maj serotype **1/2a and 4b**
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reservoir + transmission of listeriosis
**soil**
digestive tract of human, mamals, bird, fish, crusteacean
infect by **ingestion of poorly preserved silage (pH > 5.5 and aerobi c env)** during winter or early spring housing
infect **sheep and cattle > goat**
increase sensib Rambouillet sheep and Angora goat
delay between contamination and clinical signs: **2–6 weeks**
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differential BS disease
**listeria**
otitis media
**abcess** of BS or pituitary gland (depressed, have a base-wide stance with head and neck extended, bradycardia, or exophthalmia)
tumor
aberent **parasit migration**
trauma
thrombotic meningoencephalitis (**histophilus somni**)
**bacterial meningitis** (young animal)
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CFS in listeria + prognosis factor
increased total protein concentration (usually >40 mg/dL) and nucleated cell count (usually >12 cells/mL), with **mononuclear cells predominating
in small ruminants**, **neutrophils** are often observed in the CSF and, occasionally, predominate
analysis of CSF does not seem to correlate with the severity of the clinical signs or provide information on the outcome of the disease, except for **creatinine phosphokinase**
Because L monocytogenes rarely reaches the meningoventricular system, detection of the bacteria by **culture or polymerase chain reaction in the CSF is frequently negative**.
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most common infected structure in listeria
reticular formation
cranial nerves V, VII, and XII nuclei
pons and medulla oblongata
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macro and microscopic lesion with listeria
macro: mild meningeal congestion and increased turbidity of the CSF
micro: multifocal asymmetrical **brainstem microabscesses** with areas of malacia and intense perivascular cuffing with **mononuclear** cells, and meningoencephalitis. maj **PNN in microabsess**, macro in malacia. multifocal
gliosis, axonal swelling, and degeneration and neuronophagia
L monocytogenes was **isolated from brain homogenates in approx 50%**, best recovered from **refrigerated** nervous tissues.
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diagnosis of listeria
1. monocytosis is not observed in ruminants (compared to monosgast)
2. **metabolic acidosis**
3. CSF: increase PT, **monocellular cells** (sometimes **PNN** in small rum)
4. post mortem: **multifocal microabscesses** in the brainstem and isolation of L monocytogenes from infected brain tissue
5. combined **PCR in milk and ELISA in serum**
6. **culturing feed or bedding**
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treatment of listeria
penicillin, ampicillin, amoxicillin, aminoglycosides, macrolides (erythromycin), and chloramphenicol
Recomanded: **penicillin, ampicillin, and tetracycline 2–4 weeks**
proportion of isolates from a dairy environment that were resistant to penicillin, ampicillin, tetracycline, or florfenicol were 40%, 92%, 45%, and 66%, respectively
should **penetrate the intracellular space, cross the blood–brain barrier, and be bactericidal.**
**effective only when instituted early** in the disease course
Reported **survival rates in small ruminants and cattle with encephalitic listeriosis after treatment are 26% and 70%**
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zoonotic potential of listeria
raw or improperly pasteurized **milk** or milk products (cheese), processed meat products, coleslaw, and contaminated **raw** produce
including melons.
The **4b** serotype of L monocytogenes most often responsible for infections in humans.
**Cutaneous** listeriosis has been observed as result of handling aborted fetuses and placentas.
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etiology of otitis media in rmnt
**Respiratory**
tract pathogens including H somni, Mannheimia haemolytica, **Mycoplasma bovis**, and Pasteurella multocida are often isolated, as is Trueperella
pyogenes (formerly Arcanobacterium pyogenes) in more chronic cases.
M bovis, either alone or in association with other bacteria, is becoming increasingly recognized as the main etiologic agent of OMI in dairy calves
pigs: **Streptococcus spp**., particularly Streptococcus suis
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risk factor median otitis
**young** animal
**Bottle** feeding and feeding **contaminated colostrum or milk**
presence of a **coincidental respiratory infection**
OMI is usually **unilateral**, but at least 25% of cases had bilateral involvement in several reports
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most common bacterial species isolated from cases of pituitary abscess
+ maj associated infections
**T. pyogenes**
tooth abscess, mastitis, bronchopneumonia, and sinusitis (postdehorning)
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risk factor for pituitary abcess
use of **nose flaps** for weaning calves
placement of **nose rings**
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most common sign with pituitary abcess
**depression**
Signs of brainstem dysfunction and accompanying cranial nerve deficits are typically asymmetrical and include facial paralysis, dysphagia, jaw and tongue hypotonia, decreased facial sensation, and head tilt. Abnormalities found on neuroophthalmologic examination include blindness, abnormal pupillary light reflexes, strabismus, and nystagmus
**Bradycardia** is reported to occur in up to **50%** of cases and is thought to be owing to compression of the hypothalamus
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breeds predisposed to congenital cerebellar hypoplasia
Hereford
Ayrshire
Shorthorn
+ Brown swiss progressive degen myeloencephalopathy (Purkinge C, sc wm, reproductive tract, sq m)
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viral-induced cerebellar hypoplasia
1. **BVD** (125-180 d of gestation), BVD vaccine (90-118d)
2. Sheep pestivirus (**Border** disease)
3. **Schmallenberg** (+ hydranencephaly, porencephaly, dysplasia BS/SC, arthrogryphosis)
4. **Bluetongue**
5. **Ainovirus** in Japan
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virus causing polymyositis in gestation
Akabane (+ non purulent encephalomyelitis)
140
breeds predisposed to cerebellar abiotrophy
Angus
Charolais
Hereford
Shorthorn
Limousin
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plant causing cerebellar toxicity
**Solanum**: low Purkinge cells, wallerian degen cerebellar wm
**Locoweed**: mannosidase
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lysosomal storage disease in rmnt
**alpha-mannosidosis** (cerebellum): **Angus**, Murray grey, Galloway
**beta-mannosidosis** (cerebellum): **Salers**
**Mapple syrup** urine disease (cerebellum): **hereford, Shorthorn**
*GM1 gang (foreb): Friesian*
*glycogen storage (muscles): Brahman, Charolais*
**Citrullinemia** (hyperammonemia): **Holstein**
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causes of tremors in rmnt
grass straggers (**hypoMg**)
**perennial ryegrass** (GABA recept, loss Purkinge)
**Staggers** (**phalaris**, Dallis, Bermuda)
Penicillum in **moldy corn**
**Aspergillus**
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plants with muscular toxicity
**White snakeroot**:
(Ageratina altissima): toxin **tremetone**, y reluctance to move and fine muscle tremors. swelling and palor or streaking of many skeletal muscles
**Thermopsis** spp.:
toxins: quinolizidine alkaloids, anagyrine, thermopsine, cystisine, and N-methylcytisine
muscle weakness often accompanied by recumbency. Microscopically there is prominent skeletal muscle degeneration and necrosis with patchy areas of regenerations
Cassia or **Senna** spp.: myoglobinuria skeletal muscle
necrosis and degeneration that may be polyphasic making it difficult to differentiate from some
nutritional myopathies.
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Nutritionnal myelopathy in pigs
1/ Copper deficiency: rapidly progressive PL paresis/ataxia in 3.5-6 mo. Axonal degeneration
2/ Overdose of arsanilic acid: Progressive PL+/-TL paresis/ataxia
Axonal and myelin degeneration
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Infectious agent that spread into nerves in large animals
Bovine herpes virus 5
Listeriosis
Pseudorabies
Rabies
Bornavirus
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Inclusions associated with virus
Herpes virus: basophilic, intranuclear in neuron/glial cell
Rabies: negri bodies (eosinophilic inytracytoplasmic in neurons)
Pseudorabies: eosinophilic intranuclear in astrocyte
Distemper: eosinophilic, intranuclear/cytoplasmic
Borna disease: Joesty-Degen inclusion bodies nucleus > cytoplasm neuron in hippocampus
Rubarth’s disease: baso/amphophilic inclusion bodies in nuclei of endothelial cells
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gram tetanus botulism
tetanus gram +
botulism gram -
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% discharge in non ambulatory adult beef cattle
**19%** were discharged, and the remaining 81% died or were euthanized (69.8%).
The odds of being discharged increased with each **additional day of hospitalization** and **with each additional flotation therapy** session.
Down **beef cattle with a diagnosis of calving peripheral nerve paralysis and capable of walking out the tank** after the first flotation session were 6.66 and 30 times more likely to be discharged
