Difference between revisions of "Equine Viral Arteritis"

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Also known as: '''''EVA — Equine Arteritis Virus — EAV'''''
 
  
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== Introduction  ==
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====Antigenicity====
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*Most cases are subclinical and only '''antibody positive'''
  
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This is a notifiable disease of horses in the UK caused by Equine Arteritis Virus. The disease infects the nasopharynx after respiratory transmission, causing a multitude of respiratory signs. The disease can also be spread venereally. After this, the virus spread to lymphoid tissue leading to '''leukopaenia''' and '''immunosuppression'''. Then it disseminates through the circulatory system causing medial necrosis of arteries and thus haemorrhages and abortions, as well as oedema.
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====Hosts====
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Many cases are subclinical and only '''antibody positive.'''  
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*More common in '''thoroughbreds'''
  
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The disease is controlled virus in the UK but AI and breeding schemes presents a real risk.
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====Pathogenesis====
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*Infects nasopharynx and spreads locally, causing:
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**Dyspnoea
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**Coughing
 +
**Diarrhoea
 +
**Colic
 +
*Spread to lymphoid tissue leads to '''leukopenia''' and '''immunosuppression'''
 +
*Typical '''medial necrosis of arteries''' causing:
 +
**Hemorrhage
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**Abortions occur after 10-30 days in 50% of pregnant mares (as opposed to Equine Herpes, which shows late abortions)
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**Oedema - particularly ocular, giving rise to "pink eye"
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*Other clinical signs include:
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**Pyrexia
 +
**Nettle rashes
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**Ocular and nasal discharge
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**Swelling of legs or scrotum
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**Stiffness of gait
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*'''Foal death''' caused by '''interstitial pneumonia'''
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*Stallions become intermittent or persistent '''shedders''' from [[Male Reproductive Tract -Accessory Sex Glands - Anatomy & Physiology|accessory sex glands]] but may show no clinical signs
  
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== Signalment  ==
 
  
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More common in '''thoroughbreds '''than other breeds of horse. Most commonly seen in stud stallions or in broodmares.
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====Epidemiology====
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*Controlled virus in the UK but AI and breeding schemes presents a real risk
  
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== Clinical Signs  ==
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====Diagnosis====
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*Clinical symptoms, but may be variable
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*'''PCR''' on '''semen'''
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*'''ELISA''' for serum '''antibody'''
  
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Respiratory signs often appear first and these include dyspnoea, coughing and increased respiratory rate. This can also lead to [[Interstitial Pneumonia|interstitial pneumonia]]. In foals, interstitial pneumonia is the most common cause of death related to this disease. Once circulatory dissemination has occurred, diarrhoea, colic and haemorrhage will follow. Abortions occur after 10-30 days in 50% of pregnant mares (as opposed to [[Equine Herpesvirus 1|Equine Herpes]], which shows late abortions). Oedema - particularly ocular oedema is frequently present, giving rise to "pink eye". There will also be a pyrexia, rashes, ocular and nasal discharge, swelling of legs or scrotum and stiffness of gait.
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====Control====
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*'''Vaccines''':
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**Stallions: '''Live attenuated'''
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**Mares: '''Killed whole virus'''
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*Clinical disease is '''NOTIFIABLE'''
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**Seropositive stallions restricted from teasing, mating or AI unless PCR tested negative
 +
**Persistent shedders should be castrated
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*Serology on imported horses
 +
*Mares tested within 4 weeks of mating
 +
*In an outbreak, isolate and restrict movement until antibody-negative for one month
  
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Stallions become intermittent or persistent '''shedders''' from [[Accessory Sex Glands - Anatomy & Physiology|accessory sex glands]] but may show no clinical signs.
 
  
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== Diagnosis  ==
 
  
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Clinical symptoms are the usual indicator of the disease, but these may be variable.
 
  
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A '''PCR''' on '''semen '''or an [[ELISA testing|'''ELISA''']] for serum '''antibody '''can be used to gain a definitive diagnosis.
 
  
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== Control  ==
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*Causative agent: [[Arteriviridae|equine arterivirus]] (EVA)
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*[[Nasal Cavity Inflammatory - Pathology|Rhinitis]], peripheral oedema, [[Bronchi and Bronchioles Inflammatory - Pathology|bronchitis/bronchiolitis]], conjunctivitis, periorbital oedema
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*Replicates in macrophages and endothelial cells
 +
*Disseminates via the circulatory system causing necrotising arteritis
 +
*[[Lungs Inflammatory - Pathology#Interstitial pneumonia|Interstitial pneumonia]]
 +
*Transmitted by respiratory and venereal routes through direct contact with infected horse or its secretions
 +
*Stallion are a reservoir of infection as they are chronic shedders
  
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'''[[Vaccines]]:'''
 
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:Stallions require '''live attenuated''' vaccine and mares require '''killed whole virus.'''
 
  
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Seropositive stallions restricted from teasing, mating or AI unless PCR tested negative. Persistent shedders should be castrated and serology should be performed on imported horses. Mares are tested within 4 weeks of mating.
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[[Category:Arteriviridae]][[Category:Horse Viruses]]
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[[Category:To_Do_-_Viruses]]
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Clinical disease is NOTIFIABLE in the UK.
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[[Category:Respiratory_Viral_Infections]]
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[[Category:Respiratory_Disorders_-_Horse]]
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In an outbreak, isolate and restrict movement until antibody-negative for one month.
 
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== References ==
 
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Mair, T., Love, S., Schumacher, J. and Watson, E. (1998) '''Equine Medicine, Surgery and Reproduction '''''WB Saunders Company Ltd''
 
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Merck & Co (2008) '''The Merck Veterinary Manual '''(Eighth Edition) ''Merial''
 
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Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), ''Saunders''
 
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Reed, S.M, Bayly, W.M, Sellon, D.C. (2004) '''Equine Internal Medicine '''(Second Edition) ''Saunders''
 
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Robinson, N.E., Sprayberry, K.A. (2009)''' Current Therapy in Equine Medicine '''(Sixth Edition) ''Saunders Elsevier''
 
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Rose, R. J. and Hodgson, D. R. (2000)''' Manual of Equine Practice''' (Second Edition)'' Saunders''
 
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{{review}}
 
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{{OpenPages}}
 
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[[Category:Expert_Review - Horse]] [[Category:Respiratory_Viral_Infections]] [[Category:Alimentary Diseases - Horse]][[Category:Lymphoreticular and Haematopoietic Diseases - Horse]][[Category:Respiratory_Diseases_-_Horse]]
 

Revision as of 11:51, 29 July 2010


 This article is still under construction.


Antigenicity

  • Most cases are subclinical and only antibody positive

Hosts

  • More common in thoroughbreds

Pathogenesis

  • Infects nasopharynx and spreads locally, causing:
    • Dyspnoea
    • Coughing
    • Diarrhoea
    • Colic
  • Spread to lymphoid tissue leads to leukopenia and immunosuppression
  • Typical medial necrosis of arteries causing:
    • Hemorrhage
    • Abortions occur after 10-30 days in 50% of pregnant mares (as opposed to Equine Herpes, which shows late abortions)
    • Oedema - particularly ocular, giving rise to "pink eye"
  • Other clinical signs include:
    • Pyrexia
    • Nettle rashes
    • Ocular and nasal discharge
    • Swelling of legs or scrotum
    • Stiffness of gait
  • Foal death caused by interstitial pneumonia
  • Stallions become intermittent or persistent shedders from accessory sex glands but may show no clinical signs


Epidemiology

  • Controlled virus in the UK but AI and breeding schemes presents a real risk

Diagnosis

  • Clinical symptoms, but may be variable
  • PCR on semen
  • ELISA for serum antibody

Control

  • Vaccines:
    • Stallions: Live attenuated
    • Mares: Killed whole virus
  • Clinical disease is NOTIFIABLE
    • Seropositive stallions restricted from teasing, mating or AI unless PCR tested negative
    • Persistent shedders should be castrated
  • Serology on imported horses
  • Mares tested within 4 weeks of mating
  • In an outbreak, isolate and restrict movement until antibody-negative for one month



  • Causative agent: equine arterivirus (EVA)
  • Rhinitis, peripheral oedema, bronchitis/bronchiolitis, conjunctivitis, periorbital oedema
  • Replicates in macrophages and endothelial cells
  • Disseminates via the circulatory system causing necrotising arteritis
  • Interstitial pneumonia
  • Transmitted by respiratory and venereal routes through direct contact with infected horse or its secretions
  • Stallion are a reservoir of infection as they are chronic shedders
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