Skip to main content Accessibility help
×
Hostname: page-component-76d6cb85b7-dqfph Total loading time: 0 Render date: 2026-07-16T14:11:52.497Z Has data issue: false hasContentIssue false

7 - Influenza Evolution

Published online by Cambridge University Press:  10 August 2009

Robin M. Bush
Affiliation:
Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697
Nancy J. Cox
Affiliation:
Influenza Branch, Centers for Disease Control & Prevention, Atlanta, GA 30333
Krishna R. Dronamraju
Affiliation:
Foundation for Genetic Research, Houston, Texas
Get access

Summary

THE VIRUS

The influenza viruses are classified in three genera of the family Orthomyxoviridae. The genera are referred to as “types” A, B, and C. The genome, about 14 KB in size, has eight single-stranded RNA segments of negative sense (seven segments in influenza C viruses). The influenza A genome encodes three polymerase proteins (PB1, PB2, and PA); two major surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA); three structural proteins (NP, M1, and M2); and two non-structural proteins involved in nuclear export (NS1 and NS2) (Lamb, 1989). An eleventh open reading frame recently discovered within PB1 appears to code for a protein involved in host cell apoptosis (Chen et al., 2001).

Two surface glycoproteins have been the object of most evolutionary studies of influenza. Hemagglutinin (HA) is involved in binding to host cell surface receptors. Neuraminidase (NA) is necessary for release of daughter virions from host cells. These proteins protrude from the viral envelope and are exposed to host immune defenses. While the HA is the primary target for neutralizing antibodies, antibodies against NA also may reduce occurrence and severity of illness, and possibly prevent infection if present at high titer. The hemagglutinin esterase (HE) in influenza C assumes the functions of both HA and NA. Broad reviews of influenza biology can be found in Murphy and Webster (1996) and Glezen and Couch (1997).

SUBTYPES

Considerable genetic diversity exists among avian influenza A viruses (Webster et al., 1992).

Information

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Book purchase

Temporarily unavailable

Save book to Kindle

To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

  • Influenza Evolution
    • By Robin M. Bush, Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, Nancy J. Cox, Influenza Branch, Centers for Disease Control & Prevention, Atlanta, GA 30333
  • Edited by Krishna R. Dronamraju, Foundation for Genetic Research, Houston, Texas
  • Book: Infectious Disease and Host-Pathogen Evolution
  • Online publication: 10 August 2009
  • Chapter DOI: https://doi.org/10.1017/CBO9780511546259.008
Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

  • Influenza Evolution
    • By Robin M. Bush, Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, Nancy J. Cox, Influenza Branch, Centers for Disease Control & Prevention, Atlanta, GA 30333
  • Edited by Krishna R. Dronamraju, Foundation for Genetic Research, Houston, Texas
  • Book: Infectious Disease and Host-Pathogen Evolution
  • Online publication: 10 August 2009
  • Chapter DOI: https://doi.org/10.1017/CBO9780511546259.008
Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

  • Influenza Evolution
    • By Robin M. Bush, Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, Nancy J. Cox, Influenza Branch, Centers for Disease Control & Prevention, Atlanta, GA 30333
  • Edited by Krishna R. Dronamraju, Foundation for Genetic Research, Houston, Texas
  • Book: Infectious Disease and Host-Pathogen Evolution
  • Online publication: 10 August 2009
  • Chapter DOI: https://doi.org/10.1017/CBO9780511546259.008
Available formats
×