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27 Cards in this Set
- Front
- Back
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2 main types of EHV?
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EHV1 & EHV4
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There are how many EHV in total? How many affect horses; donkeys?
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8; 1-5;6-8
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T/F: In less severe cases of EHV disease frequently goes unrecognized.
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T
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Pathogenesis of respiratory form of EHV-1 & EHV-2? 7 steps
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1. contracted by inhalation of aerosolized particles
2. intitially gains entrance via respiratory tract - usually young horses 3. 2-10d incubation 4. replicates in nasopharynx and lymphoreticular tissue of respiratory tract 5. May be limited to respiratory tract or virus is picked up by macrophages or leukocytes and transported to other ts (this is why we see mulitple sites w/EHV rather than flu) 6. immunologic mechanisms affect dz process 7. virus-specific Ab directed against surface glycoproteins is partially protective |
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Respiratory form of EHV-4 is not associated with __ infection or __ dz, but can rarely cause sporatic __.
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neonatal; neurologic; abortions
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EHV-1 is commonly associated with which CS?
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respiratory, abortion, neonatal dz, neurologic
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EHV-4 is commonly ass. with which CS?
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respiratory
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When does EHV-1 typically affect gestation?
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late
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Is a viremia required to cause abortion by EHV-1?
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yes
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How does EHV-1 affect the mare during gestation?
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Attacks uterine endothelial cells --> vasculitis, thrombosis, necrosis
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How does EHV-1 affect the fetus in late (not near term) gestation?
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Crosses placenta and attacks fetus --> fetal death; virus can be isolated from lung, liver, spleen, thymus
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How does EHV-1 affect the fetus at near term gestation?
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Pathology in liver, lymphoreticular tissues, adrenal glands
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How do the near term gestation foals die?
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They are born weak and succumb to bacterial infections
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What CS can be used to distiquish EHV from flu?
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EHV - has NO characteristic cough
Flu - has characteristic cough |
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EHV-1 in the neurologic form tends to affect who?
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all ages, all breeds
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How are EHV-1 in the neurologic cases often found? (i.e. pandemic, isolated, sporatic?)
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isolated
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EHV-1 in the neurologic form will have what progression of CS?
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Sudden onset - max signs in 48hrs
1. ascending paraltic syndrome 2. urinary incontinence, poor anal/tail tone, weakness, ataxia 3. progresses up body, paraplegia/quadriplegia 4. CN signs usually absent |
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EHV-1 in the neurologic form causes an Ag-Ab disorder, an immune-mediated vasculitits. What happens?
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Type III hypersensitivity
Affects vasculature of neurologic system Infection of endothelial cells by leukocytes with EHV-1 virus Inflammatory immune reaction to EHV-1 Ag |
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EHV-1 in the neurologic form causes what lesion?
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Eosinophilic perivascular cuffing
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Dx of EHV of the respiratory form is based mostly on?
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CS
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How can PCR be helpful in EHV of the respiratory form?
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distinquish b/w latent and active infection
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Dx of EHV of the neurologic form is based mostly on?
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CS, Hx, CSF is often yellow colored - xanthochromia
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Tx of the respiratory form? (4)
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Supportive care
Antiinflam drug Ab to control 2nd bacterial infection Immunostimulants |
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Tx of the neurologic form? (4)
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CORTICOSTEROIDS
IV Fluids IV DMSO Padded support |
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Px for neurologic EHV is determined how?
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Good = standing
Poor = recumbent |
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How to control EHV (5)
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iso
increase ventilation suspend work/traning min traffic vacc |
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Prevent EHV
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Vacc - to control abortion and most resp... nothing for neuro
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