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− | {{unfinished}}
| + | == Introduction<br> == |
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− | ====Antigenicity==== | + | 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 venerally. After this, the virus spread to lymphoid tissue leading to<span style="font-weight: bold;"> </span>'''leukopenia''' and '''immunosuppression'''. Then it disseminates through the circulatory system causing medial necrosis of arteries occurs causing haemorrhages and abortions, as well as oedema.<br> |
− | *Most cases are subclinical and only '''antibody positive'''
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− | ====Hosts====
| + | Many cases are subclinical and only '''antibody positive.''' |
− | *More common in '''thoroughbreds'''
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− | ====Pathogenesis====
| + | The disease is controlled virus in the UK but AI and breeding schemes presents a real risk.<br> |
− | *Infects nasopharynx and spreads locally, causing:
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− | **Dyspnoea
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− | **Coughing
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− | **Diarrhoea
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− | **Colic
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− | *Spread to lymphoid tissue leads to '''leukopenia''' and '''immunosuppression'''
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− | *Typical '''medial necrosis of arteries''' causing:
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− | **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
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− | **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 [[Accessory Sex Glands - Anatomy & Physiology|accessory sex glands]] but may show no clinical signs
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− | ====Epidemiology==== | + | == Signalment<br> == |
− | *Controlled virus in the UK but AI and breeding schemes presents a real risk
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− | ====Diagnosis====
| + | More common in '''thoroughbreds '''than other breeds of horse. Most commonly seen in studs or in brood mares. |
− | *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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− | ====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
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− | **Persistent shedders should be castrated
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− | *Serology on imported horses
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− | *Mares tested within 4 weeks of mating
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− | *In an outbreak, isolate and restrict movement until antibody-negative for one month
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| + | == Clinical Signs<br> == |
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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. In foals, interstitial pneumonia is the most common cause of death related to this disease. Once circulatory dissemination has occured, diarrhoea, colic and haemorrhage will occur. Abortions occur after 10-30 days in 50% of pregnant mares (as opposed to Equine Herpes, which shows late abortions). Oedema - particularly ocular odema is frequently present, giving rise to "pink eye". There will also be a pyrexia, rashes, ocular and nasal discharge, swelling of legs or scrotum ans stiffness of gait. |
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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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| + | <br> |
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− | *Causative agent: [[Arteriviridae|equine arterivirus]] (EVA)
| + | == Diagnosis == |
− | *[[Rhinitis|Rhinitis]], peripheral oedema, [[Bronchitis|bronchitis/bronchiolitis]], conjunctivitis, periorbital oedema
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− | *Replicates in macrophages and endothelial cells
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− | *Disseminates via the circulatory system causing necrotising arteritis
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− | *[[Interstitial Pneumonia|Interstitial pneumonia]]
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− | *Transmitted by respiratory and venereal routes through direct contact with infected horse or its secretions
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− | *Stallion are a reservoir of infection as they are chronic shedders
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| + | Clinical symptoms are the usual indicator of the disease, but these may be variable. |
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− | [[Category:Arteriviridae]][[Category:Horse Viruses]]
| + | A '''PCR''' on '''semen '''or an '''ELISA''' for serum '''antibody '''can be used to gain a definative diagnosis. |
− | [[Category:To_Do_-_Clinical/Viruses]] | + | |
− | [[Category:Respiratory_Viral_Infections]] | + | <br> |
− | [[Category:Respiratory Diseases - Horse]] | + | |
| + | <br> |
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| + | == Control == |
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| + | '''Vaccine'''tallions require '''Live attenuated''' vaccine and mares require '''Killed whole virus. '''<span style="font-weight: bold;"> </span>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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| + | Clinical disease is NOTIFIABLE. |
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| + | In an outbreak, isolate and restrict movement until antibody-negative for one month <br> |
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| + | <br> |
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| + | == References<br> == |
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| + | Mair, T., Love, S., Schumacher, J. and Watson, E. (1998) Equine Medicine, Surgery and Reproduction WB Saunders Company Ltd<br>Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial <br>Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) Equine Internal Medicine (Third Edition), Saunders.<br>Reed, S.M, Bayly, W.M, Sellon, D.C. (2004) Equine Internal Medicine (Second Edition) Saunders.<br>Robinson, N.E., Sprayberry, K.A. (2009) Current Therapy in Equine Medicine (Sixth Edition) Saunders Elsevier<br>Rose, R. J. and Hodgson, D. R. (2000) Manual of Equine Practice (Second Edition) Sauders. <br><br> |
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| + | [[Category:To_Do_-_Review]] [[Category:Respiratory_Viral_Infections]] [[Category:Respiratory_Diseases_-_Horse]] |