Antigenic Shift v. Drift in Avian and Mammalian Sino-Influenza Type A Viruses.

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Antigenic Shift v. Drift in Avian and Mammalian
Sino-Influenza Type A Viruses.

• By
• Charles Hauser, St. Edwards University
• Mark Maloney, Spelman College
• Young Kim, Northland College
• Michael P. Saclolo, St. Edwards University

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Issues

• Role of viral hemagglutinin diversity in
  pathology
• Creation of new viral strains
• Antigenic shift versus drift

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Influenza type A

• Subtypes designated by Hemagglutinin (H) and
  Neuraminidase (N) expression

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Subtypes

• H and N are on surface
• H and N are components of flu vaccines
• Subtypes A (H1N1) and A (H3N2) are common human
  viruses

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Vaccines must match subtype and specific strain

• New flu viruses evade immunity
• Antigenic Shift vs.
• Antigenic Drift

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Antigenic Shift

• New subtypes match different H and N genes
• Avian and human viruses mix and match in swine

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Antigenic Drift

• Small differences in sequence within a subtype
  define strains
• alleles or different versions of same H genes

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BIRD FLU

• Bird flu is unusual
• Some strains of avian subtypes (H5N1, H9N2, H7N7)
  can directly infect humans

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Module Components

• Chinese Avian and Mammalian Influenza
  Hemagglutinin Sequences
• ClustalW Alignment
• Dendogram Analysis

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H9N2
H3N2
H1N1
H5N1
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