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New page: {{unfinished}} {{toplink |linkpage =Viruses |linktext =VIRUSES |sublink1=Orthomyxoviridae |subtext1=INFLUENZA |pagetype =Bugs }} <br> ===Subtypes=== *Two subtypes of Equine Influenza hav...
{{unfinished}}
{{toplink
|linkpage =Viruses
|linktext =VIRUSES
|sublink1=Orthomyxoviridae
|subtext1=INFLUENZA
|pagetype =Bugs
}}
<br>
===Subtypes===
*Two subtypes of Equine Influenza have been described:
**H7N7 (Equine 1), which was prevalent in the UK between 1963-1977
**H3N8 (Equine 2), or the European strains, have been circulating since 1965
*Some drift has occurred, causing outbreaks of North-American-like strains of H3N8 in 1998 (EU) and 2003 (South America)
===Pathogenesis===
*Aerosol and fomite transmission infects the epithelium of the upper respiratory tract, resulting in cell necrosis
*This manifests a bronchiolitis and serous exudation
*1-3 day incubation period
*Excretion of the virus in nasal secretions peaks at 3-4 days and finishes by 10 days
*Clinical signs:
**Harsh dry cough
**Pyrexia (103-106F)
**Depression
**Loss of appetite
**Enlarged submandibular lymph nodes
*Secondary bacterial infection can follow defective muco-ciliary transport, eg ''Streptococcus zooepidemicus''
*For more, see [[Respiratory Viral Infections - Pathology#Equine influenza|here]]
===Diagnosis===
*Virus isolation: Deep nasal swabs (12 inches) deposited into 10ml of transport medium and transported at 4C
*Antigen detection via ELISA: tests for type A nucleoprotein
*Serology provides a retrospective diagnosis by '''Haemagglutination Inhibition (HI)''':
**Acute and Convalescent (2 weeks post-acute) samples are tested from the same animal
**4-fold increase of HI must be shown to confirm diagnosis
===Control===
*Isolate coughing horses to minimize spread
*Vaccination:
**All vaccines include H7 and varieties of the current circulating strains of H3
**'''Inactivated'''egg-grown vaccing is produced with alhydrogel as an adjuvant
**'''Live''' vaccines using purified haemagglutinin do not require adjuvants
**UK Jockey Club rules regarding timing:
***Horses must be certified as completing a vaccination course of 3 injections at least 10 days prior to racing
***The course consists of a primary inoculation followed by a second within 21-92 days and a third after a further 150-215 days
***Boosters are given annually to maintain immunity, and in the event a year is missed the initial course of three jabs must be repeated
{{toplink
|linkpage =Viruses
|linktext =VIRUSES
|sublink1=Orthomyxoviridae
|subtext1=INFLUENZA
|pagetype =Bugs
}}
<br>
===Subtypes===
*Two subtypes of Equine Influenza have been described:
**H7N7 (Equine 1), which was prevalent in the UK between 1963-1977
**H3N8 (Equine 2), or the European strains, have been circulating since 1965
*Some drift has occurred, causing outbreaks of North-American-like strains of H3N8 in 1998 (EU) and 2003 (South America)
===Pathogenesis===
*Aerosol and fomite transmission infects the epithelium of the upper respiratory tract, resulting in cell necrosis
*This manifests a bronchiolitis and serous exudation
*1-3 day incubation period
*Excretion of the virus in nasal secretions peaks at 3-4 days and finishes by 10 days
*Clinical signs:
**Harsh dry cough
**Pyrexia (103-106F)
**Depression
**Loss of appetite
**Enlarged submandibular lymph nodes
*Secondary bacterial infection can follow defective muco-ciliary transport, eg ''Streptococcus zooepidemicus''
*For more, see [[Respiratory Viral Infections - Pathology#Equine influenza|here]]
===Diagnosis===
*Virus isolation: Deep nasal swabs (12 inches) deposited into 10ml of transport medium and transported at 4C
*Antigen detection via ELISA: tests for type A nucleoprotein
*Serology provides a retrospective diagnosis by '''Haemagglutination Inhibition (HI)''':
**Acute and Convalescent (2 weeks post-acute) samples are tested from the same animal
**4-fold increase of HI must be shown to confirm diagnosis
===Control===
*Isolate coughing horses to minimize spread
*Vaccination:
**All vaccines include H7 and varieties of the current circulating strains of H3
**'''Inactivated'''egg-grown vaccing is produced with alhydrogel as an adjuvant
**'''Live''' vaccines using purified haemagglutinin do not require adjuvants
**UK Jockey Club rules regarding timing:
***Horses must be certified as completing a vaccination course of 3 injections at least 10 days prior to racing
***The course consists of a primary inoculation followed by a second within 21-92 days and a third after a further 150-215 days
***Boosters are given annually to maintain immunity, and in the event a year is missed the initial course of three jabs must be repeated