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antigenic drift

TWiV 557: Congress in Rotterdam

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From the European Congress of Virology in Rotterdam, Vincent and local co-host Ben Berkhout speak with Ron Fouchier, Rosina Girones, and Marie-Paule Kieny about their careers and their work on influenza virus, environmental virology, and developing an Ebola virus vaccine during an epidemic.

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Show notes at microbe.tv/twiv

TWiV 480: The PFU in your achoo

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Scott Hensley joins the TWiVites to review the current influenza season and presence of the virus in exhaled breath of symptomatic cases.

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Scott Hensley of the University of Pennsylvania helps us summarize the current influenza season so far. Bottom line: it’s a very serious season with a great deal of morbidity and mortality. As usually, serious disease and deaths occur in unvaccinated individuals. Although there is a mismatch between the influenza vaccine and this year’s H3N2 strain, which is causing most of the infections, vaccination still reduces disease severity cause by this strain, as well as by the circulating H1N1 and influenza B viruses. Next we discuss an interesting study of symptomatic college students with influenza. The goal was to determine which mode of influenza transmission is likely to be important: contact, or aerosols produced by speaking, coughing, or sneezing. The results show that simple breathing leads to virus in the breath – small aerosols that can travel distances to infect others. Coughing, but not sneezing, was a major observed sign of infection, but neither was needed for infectious aerosol generation.

How a toupee compromised influenza vaccine

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The influenza virus vaccine is frequently updated to ensure that it protects against infection with circulating virus strains. In some years the vaccine matches the circulating strains, but in others, there is a mismatch. The result is that the vaccine is less effective at protecting from infection. During the 2014-15 influenza season there was a mismatch due to growing the vaccine in embryonated chicken eggs.

[Read more…] about How a toupee compromised influenza vaccine

Derek Smith on antigenic cartography

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Derek Smith, Professor of Infectious Disease Informatics, University of Cambridge, U.K., has developed a method for visualizing antigenic evolution by creating two-dimensional maps in a process called antigenic cartography. These maps are made with data that provide information on the antigenic properties of the pathogen. In the case of influenza virus, the data come from measuring the ability of an antiviral antibody to inhibit hemagglutination – binding of virions to red blood cells. Such maps show how amino acid changes can affect antibody binding to virus particles, which cannot be done by comparing nucleotide sequences of different virus isolates. By charting influenza virus strains in this way, it should be possible to better understand genetic and antigenic evolution.

I discussed antigenic cartography with Dr. Smith during ICAAC Boston 2010, as part of TWiV 99. View the video below, or right click to download the 292 MB .mp4 file.

TWiV 99: ICAAC Boston 2010

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Host: Vincent Racaniello

Vincent tours the 50th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Boston, speaking with exhibitors and visitors, including Professors Derek Smith, Michael Schmidt, Frederick Hayden, and Myra McClure.

Many thanks to Chris Condayan and Ray Ortega of the American Society for Microbiology for recording and editing this episode.

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