Featured Research

from universities, journals, and other organizations

New Study Has Important Implications For Flu Surveillance

Date:
October 27, 2006
Source:
NIH/National Library of Medicine
Summary:
Researchers are reporting the results of a study that dramatically alters the existing understanding of how the influenza virus evolves. The findings could have important implications for monitoring changes to the virus and predicting which strains should be used for flu vaccine.

Researchers are reporting results of a study that substantially alters the existing understanding of how the influenza virus evolves and that could have important implications for monitoring changes to the virus and predicting which strains should be used for flu vaccine. The study, which will be published in the online journal Biology Direct Oct. 26, 2006, was conducted by researchers from the National Library of Medicine's National Center for Biotechnology Information (NCBI) and Fogarty International Center , both part of the National Institutes of Health.

In an effort to better understand how seasonal influenza evolves into new strains, the researchers analyzed the genomic sequences of a large and representative collection of the two most common flu strains (called H3N2 and H1N1) from the 1995-2005 flu seasons in New York state and New Zealand. The sequence data was obtained from the Genome Sequencing Project , which recently generated over 1,000 fully sequenced influenza genomes from clinical isolates; the project is funded and managed by the National Institute of Allergy and Infectious Diseases .

The analysis revealed a picture of flu evolution that was surprisingly different from the prevailing conception of how the virus changes. Evolution of influenza A virus is commonly viewed as a typical Darwinian process. In this mode of evolution, the virus' main surface protein, hemagglutinin (HA), is thought to continually change to evade human immune response, resulting in new dominant strains that eliminate all competitors in a series of rapid successions. Unexpectedly, however, the study found that the periods of intense Darwinian selection accounted for only a relatively small portion of H3N2 flu evolution during the ten-year period examined.

The study found that much of the time the H3N2 virus seemed to be "in stasis"; that is, the HA gene showed no significant excess of mutations in the antigenic regions (those recognized by the immune system). During these stasis periods, none of the co-circulating strains is significantly more fit than others, apparently because multiple mutations are required to substantially improve the virus' ability to evade the immune system. As a result, an increased variety of strains accumulates. Ultimately, however, one of the variants will come within one mutation of achieving higher fitness and becoming dominant. Once the crucial last mutation does occur, virus evolution shifts from stasis to a brief interval of rapid Darwinian evolution, where the new dominant virus rapidly sweeps through the human population and eliminates most other variants.

Based on their results, the researchers conclude that "the common view of the evolution of influenza virus as a rapid, positive selection-driven process is, at best, incomplete." Because the periods of stasis allow the proliferation of many small groups of related viruses, any of which could become the next dominant virus strain, the authors suggest that sequencing much larger numbers of representative isolates could be helpful in augmenting current surveillance methods.

The study, titled "Long Intervals of Stasis Punctuated by Bursts of Positive Selection in the Seasonal Evolution of Influenza A Virus," is authored by Yuri Wolf, PhD, NCBI; Cecile Viboud, PhD, Fogarty International Center; Edward Holmes, PhD, Fogarty International Center and Pennsylvania State University; Eugene Koonin, PhD, NCBI; and David Lipman, MD, NCBI.

Established in 1988 as a national resource for molecular biology information, NCBI creates public databases, conducts research in computational biology, develops software tools for analyzing molecular and genomic data, and disseminates biomedical information - all for the better understanding of processes affecting human health and disease. NCBI is a division of the National Library of Medicine at the National Institutes of Health (NIH).


Story Source:

The above story is based on materials provided by NIH/National Library of Medicine. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Library of Medicine. "New Study Has Important Implications For Flu Surveillance." ScienceDaily. ScienceDaily, 27 October 2006. <www.sciencedaily.com/releases/2006/10/061026185115.htm>.
NIH/National Library of Medicine. (2006, October 27). New Study Has Important Implications For Flu Surveillance. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2006/10/061026185115.htm
NIH/National Library of Medicine. "New Study Has Important Implications For Flu Surveillance." ScienceDaily. www.sciencedaily.com/releases/2006/10/061026185115.htm (accessed July 22, 2014).

Share This




More Health & Medicine News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com
Tooth Plaque Provides Insight Into Diets Of Ancient People

Tooth Plaque Provides Insight Into Diets Of Ancient People

Newsy (July 19, 2014) Research on plaque from ancient teeth shows that our prehistoric ancestor's had a detailed understanding of plants long before developing agriculture. Video provided by Newsy
Powered by NewsLook.com
Contaminated Water Kills 3 Babies in South African Town

Contaminated Water Kills 3 Babies in South African Town

AFP (July 18, 2014) Contaminated water in South Africa's northwestern town of Bloemhof kills three babies and hospitalises over 500 people. The incident highlights growing fears over water safety in South Africa. Duration: 02:22 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins