TYPES AND SUBTYPES OF THE INFLUENZA VIRUS

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TYPES AND SUBTYPES OF THE INFLUENZA VIRUS
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Classification
RNA virus
Family
Genus
Types
Kingsbury DW. In Fields BN et al., eds.
Virology. 2nd Edn. New York Raven Press 1990
107687. Photo courtesy of Linda Stannard,
University of Cape Town, South Africa.
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Influenza subgroups

• Influenza A
• highly infective
• infects many species
• causes widespread epidemics
• Influenza B
• found only in humans
• capable of producing severe disease
• causes regional epidemics
• Influenza C
• causes mild disease
• humans are natural hosts, but isolates also found
  in pigs
• does not cause epidemics

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The virus nomenclature
Classification of the human influenza viruses
For example A / Beijing / 32 / 92 (H3N2)
A virus type, here A
Beijing place where the strain was isolated
32 strain number
92 year of first isolation
H3N2 subtypes H3 and N2 virus type, here H3N2
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By courtesy of APACIAsia-Pacific Advisory
Committee on influenzawww.apaci-flu.com