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| =Influenza by Species= | | =Influenza by Species= |
− | ==Equine Influenza== | + | ===[[Equine Influenza]]=== |
− | ===Subtypes===
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− | *Two subtypes of Equine Influenza have been described:
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− | **H7N7 (Equine 1), which was prevalent in the UK between 1963-1977
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− | **H3N8 (Equine 2), or the European strains, have been circulating since 1965
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− | *Some drift has occurred, causing outbreaks of North-American-like strains of H3N8 in 1998 (EU) and 2003 (South America)
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− | ===Pathogenesis===
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− | *Aerosol and fomite transmission infects the epithelium of the upper respiratory tract, resulting in cell necrosis
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− | *This manifests a bronchiolitis and serous exudation
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− | *1-3 day incubation period
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− | *Excretion of the virus in nasal secretions peaks at 3-4 days and finishes by 10 days
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− | *Clinical signs:
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− | **Harsh dry cough
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− | **Pyrexia (103-106F)
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− | **Depression
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− | **Loss of appetite
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− | **Enlarged submandibular lymph nodes
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− | *Secondary bacterial infection can follow defective muco-ciliary transport, eg ''Streptococcus zooepidemicus''
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− | *For more, see [[Respiratory Viral Infections - Pathology#Equine influenza|here]]
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− | ===Diagnosis===
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− | *Virus isolation: Deep nasal swabs (12 inches) deposited into 10ml of transport medium and transported at 4C
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− | *Antigen detection via ELISA: tests for type A nucleoprotein
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− | *Serology provides a retrospective diagnosis by '''Haemagglutination Inhibition (HI)''':
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− | **Acute and Convalescent (2 weeks post-acute) samples are tested from the same animal
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− | **4-fold increase of HI must be shown to confirm diagnosis
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− | ===Control===
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− | *Isolate coughing horses to minimize spread
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− | *Vaccination:
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− | **All vaccines include H7 and varieties of the current circulating strains of H3
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− | **'''Inactivated'''egg-grown vaccing is produced with alhydrogel as an adjuvant
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− | **'''Live''' vaccines using purified haemagglutinin do not require adjuvants
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− | **UK Jockey Club rules regarding timing:
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− | ***Horses must be certified as completing a vaccination course of 3 injections at least 10 days prior to racing
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− | ***The course consists of a primary inoculation followed by a second within 21-92 days and a third after a further 150-215 days
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− | ***Boosters are given annually to maintain immunity, and in the event a year is missed the initial course of three jabs must be repeated
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| ==Swine Influenza== | | ==Swine Influenza== |