Equine - EAV Flashcards
1
Q
What is the structure of arteritis viruses?
A
- (+)ssRNA
- Enveloped
2
Q
What is Equine viral arteritis?
A
- caused by Equine arteritis virus
- Acute, contagious disease of equids
- Viral respiratory pathogen
- less common thatn EIV and EHV
- can cause abortion and neonatal death
- Persistently infected carrier stallions = reservoir
3
Q
Who are the most susceptible to EAV?
A
- Very young
- stressed, debilitated
- very aged
4
Q
How is EAV transmitted?>
A
- In utero
- Aerosolized respiratory tract secretions
- primary route of dissemination during acute infection
- Venereal
- primarily in sperm-rich fraction of semen
- Indirect contact (infrequent)
5
Q
What is the pathogenesis of EAV?
A
- Inhalation - infects and replicates in Nasopharyngeal epithelium, tonsils, bronchial and alveolar macrophages (24hrs)
- virus spreads to regional lymphatics by monocytes and lymphocytes (48 hrs)
- Disseminates throughout body - cause panvasculitis that gives rise to edema an hemorrhage (72 hrs)
6
Q
What are the clinical signs of EVA?
A
- Most subclinical
- Fever
- Depression
- Inappetence
- dependent edema (lower hind limbs, scrotum, prepuce, ventrum
- Conjunctivitis and lacrimation
- supraorbital or periorbital edema
- Nasal discharge
- Respiratory Distress or dyspnea
- Diarrhea
- Urticarial-type skin reaction
- Decreased fertility
- leukopenia
- potential for abortion
7
Q
When do abortions occur with EAV?
A
- Between 1-4 weeks after EAV exposure
- anytime between 2-10 months gestation
- rates vary from 10-70% - strain dependent
- May not abort - give birth to a congenitally infected foal
- neonatal foals may develop fulminating interstitial pneumonia
- foals 1-3 months old may develop progressive pneumoenteric disease
8
Q
What lesions are seen on foals from EVA?
A
- Pulmonary edema
- emphysema
- interstitial pneumonia
- enteritis
- splenic infarcts
- Interlobular edema, congestion, and mononuclear cell infiltration in lungs
- lymphoid depletion and hemorrhage in lymphoreticular tissue
- Focal hemorrhage and necrosis of intestinal mucosa
9
Q
What are the gross lesions associated with EVA (adults)?
A
- characterized by vascular damage
- Edema, congestion and hemorrhage
- Subcutis of limbs and abdomen
- Excess peritoneal, pleural and pericardial fluid
- Edema and hemorrhage of the intra-abdominal and thoracic lymph nodes, small and large intestine
10
Q
What are the microscopic lesions associated with EVA (adults)?
A
- characterized by vasculitis
- range between:
- vascular and perivascular edema with occasional lymphocytic infiltration and endothelial cell hypertrophy
- fibrinoid necrosis of the tunica media, extensive lymphocytic infiltration, necrosis of endothelium and thrombus formation
11
Q
Wen is infectious EAV no longer detectable in most tissues and body fluids?
A
28 dpi
12
Q
How many males become persistent EAV carriers?
A
- 10-70%
- EAV persistently infects the repro epithelium
- Ampulla of the vas deferens, epididymis, testes, seminiferous tubules, accessory sex glands
13
Q
How is EAV diagnosed?
A
- Virus isolation
- PCR
- IHC
- Paired Ab titers (3-4 weeks apart)
14
Q
How are EAV carrier stallions diagnosed?
A
PCR/Virus isolation of sperm-rich fraction of ejaculate
15
Q
How is EAV diagnosed as the cause of an abortion?
A
- Virus isolation, IHC, or PCR
- Placental tissues or fetal tissues (lung, liver, lymphoreticular tissues, peritoneal or pleural fluid)
