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Porcine Reproductive and Respiratory Syndrome (view source)
Revision as of 15:49, 27 August 2010
, 15:49, 27 August 2010no edit summary
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Also known as: PRRS
==Description==
*The syndrome is caused by a small enveloped RNA virus which belongs to the new [[Arteriviridae|Arteriviridae]] group
*Replicates in and destroys macrophages and endothelial cells causing vasculitis -> viraemia -> virus shedding (nasal secretions, faeces)
*Clinical signs: respiratory and reproductive failure, weaned pigs, tachypnoea, eyelid oedema, conjunctivitis
*Moderate to severe interstitial [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]] in the cranial lobe
*Superimposed bacterial infections are common
*Infectious disease in swine that emerged 10 years ago
*Today, PRRS is endemic in many if not all the pig-producing countries
PRRS Porcine reproductive and respiratory syndrome virus (Lelystad virus). There is abortion late in gestation with respiratory tract illness in live piglets (interstitial pneumonia).
==Virus==
====Antigenicity====
====Antigenicity====
*Isolates vary in virulence
*Isolates vary in virulence
*Pigs: aka '''Blue Ear''' or '''Lelystad virus'''
*Pigs: aka '''Blue Ear''' or '''Lelystad virus'''
====Pathogenesis====
==Transmission and Epidemiology==
*Discovered in Holland in 1990
*'''Highly contagious'''
*Survives well on '''fomites'''
*Transfer may also be '''aerosol''' or via '''semen'''
*Exacerbated by immunosuppression (eg by porcine circovirus 2)
==Pathogenesis==
*Infects alveolar macrophages, followed by '''interstitial pneumonitis'''
*Infects alveolar macrophages, followed by '''interstitial pneumonitis'''
*Persistent infection of '''[[Monocytes]]''' followed by '''leukopenia and thrombocytopenia'''
*Persistent infection of '''[[Monocytes]]''' followed by '''leukopenia and thrombocytopenia'''
*Transplacental spread leads to '''abortion, mummification, or resorption'''
*Transplacental spread leads to '''abortion, mummification, or resorption'''
====Epidemiology====
==Diagnosis==
====Diagnosis====
===Clinical Signs===
**Thumping respiration
**Thumping respiration
**Abortions
**Abortions
**Eyelid oedema
**Eyelid oedema
**Weak or dying piglets
**Weak or dying piglets
===Laboratory Tests+
*'''ELISA''' for virus '''antibody'''
*'''ELISA''' for virus '''antibody'''
*Rising antibody titres as a retrospective diagnosis (4X increase)
*Rising antibody titres as a retrospective diagnosis (4X increase)
==Control==
*Certified '''Specific Pathogen Free''' units exclude by quarantine
*Certified '''Specific Pathogen Free''' units exclude by quarantine
*Management: all in/all out, screening AI semen
*Management: all in/all out, screening AI semen
*'''Vaccine''' available
*'''Vaccine''' available
==Prognosis==
===Porcine reproductive and respiratory syndrome===
==Links==
==References==
[[Category:Arteriviridae]]
[[Category:Arteriviridae]]