Featured Research

from universities, journals, and other organizations

Bird Flu Genome Study Shows New Strains, Western Spread

Date:
April 19, 2007
Source:
University Of Maryland
Summary:
A recent study shows three distinct, independently evolving lineages of Avian Flu. The broad dispersal of the different forms of the virus throughout several different countries over a relatively short period of time points to the possibility of human movement, rather than wild birds as the reason for the quick spread of the H5N1.

In a paper in the May issue of Emerging Infectious Diseases, an international team of researchers, including University of Maryland professor Steven Salzberg, report the first ever large-scale sequencing of western genomes of the deadly avian influenza virus, H5N1.

Related Articles


Their study of 36 genomes of the virus collected from wild birds in Europe, the Middle East and Africa (EMA), and Vietnam confirms not only that the virus has very recently spread west from Asia, but that two of the new western strains have already independently combined, or reassorted, to create a new strain.

Several samples also contained the mutation associated with the form of the "bird flu" that caused several human deaths in 2006. It is the virus's ability to rapidly mutate into a pathogen that may eventually be passed between humans that concerns health officials about a worldwide pandemic of H5N1 influenza.

The study also produced some evidence that strengthens the case that humans have had an impact on the movement of the flu out of Asia .

"This is the first time anyone's looked at all of the H5N1 genomes in the west," said Steven Salzberg, the study's lead author and director of the University of Maryland Center for Bioinformatics and Computational Biology. "Until now, the studies have been primarily on samples from the Far East . Our study shows that the virus is spreading west, and that there have been three separate introductions of H5N1 in Europe, the Middle East and Africa."

New Strains Confirmed

The study's researchers, an unusual team of scientists from 11 countries that range from U.S. to Iran, collaborated to share data and sequence H5N1 samples taken from birds in a widely dispersed geographic region that includes Nigeria, Niger, Sudan, Egypt, Afghanistan, Iran, Slovenia, Croatia and Italy.

"We found that the EMA strains of the virus are distinct from the Vietnamese and other Asian strains," said Salzberg, "and that they have already divided into three separate new strains. One of the new strains has been the cause of several fatal human cases in Egypt and Iraq."

The research showed that the three new strains, called clades, evolved independently and in different regions from a single genetic source. "Our analysis places this source most recently in either Russia or Quinghai Province in China," Salzberg said.

The study shows that the new Euro-African lineage, which was the cause of fatal human infections in Egypt and Iraq in 2006, has been introduced at least three times into the EMA region and has split into three distinct, independently evolving lineages. Two of those sublineages have recently reassorted.

The broad dispersal of the different forms of the virus throughout the different countries over a relatively short period of time points to the possibility of human movement, rather than wild birds as the reason for the quick spread of the H5N1. "The migratory pathways of wild birds don't correspond with the movement of the genomes that we sequenced," said Salzberg. "Humans carry chickens between many of the countries in our study, often transporting them across great distances. That and the weak biosecurity standards in most rural areas point to human-related movement of live poultry as the source of the introduction of H5N1 in some countries."

While the study "dramatically increased the number of genomes that have been sequenced, we have to do more surveys," Salzberg said. "It's surprising that we found what we did with such a small sample."

International Effort

The senior author of the study was Ilaria Capua of the Istituto Zooprofilattico Sperimentale delle Venezie, Padova, Italy. Other authors included researchers from Egypt, England, Cτte d'Ivoire, Vietnam, Nigeria, Iran, Afghanistan, Croatia and Slovenia.

"The research team represents an unprecedented collaboration among authors from many remote laboratories," said Salzberg. "Collaborations like this one are essential if the scientific community is going to keep track of avian flu, but most influenza researchers continue to work in isolation, and to work with a limited and exclusive set of collaborators.

"We have to recognize that the flu knows no boundaries, and we must not only collaborate widely, but also share our data freely with one another, as we have in this study."

The flu genomes in this study were all deposited in Genbank, a public database, immediately after sequencing.

The study was funded by the U.S. National Institute of Allergy and Infectious Diseases, U.S. National Library of Medicine, U.S. Army Research Office, the Italian Ministry of Health, the European Commission for the AVIFLU and FLUAID projects, and the World Organization for Animal Health and the Food and Agricultural Organization of the United Nations.

Emerging Infectious Diseases is a journal of the Centers for Disease Control and Prevention.


Story Source:

The above story is based on materials provided by University Of Maryland. Note: Materials may be edited for content and length.


Cite This Page:

University Of Maryland. "Bird Flu Genome Study Shows New Strains, Western Spread." ScienceDaily. ScienceDaily, 19 April 2007. <www.sciencedaily.com/releases/2007/04/070418211906.htm>.
University Of Maryland. (2007, April 19). Bird Flu Genome Study Shows New Strains, Western Spread. ScienceDaily. Retrieved January 29, 2015 from www.sciencedaily.com/releases/2007/04/070418211906.htm
University Of Maryland. "Bird Flu Genome Study Shows New Strains, Western Spread." ScienceDaily. www.sciencedaily.com/releases/2007/04/070418211906.htm (accessed January 29, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Thursday, January 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Brawling Pandas Are Violently Adorable

Brawling Pandas Are Violently Adorable

Buzz60 (Jan. 29, 2015) — Video of pandas play fighting at the Chengdu Research Base in China will make your day. Mara Montalbano (@maramontalbano) shows us. Video provided by Buzz60
Powered by NewsLook.com
Why Researchers Say We Should Cut Back On Biofuels

Why Researchers Say We Should Cut Back On Biofuels

Newsy (Jan. 29, 2015) — Biofuels aren&apos;t the best alternative to fossil fuels, according to a new report. In fact, they&apos;re quite a bad one. Video provided by Newsy
Powered by NewsLook.com
3-D Printed Wheelchair Helps Two-Legged Dog Learn to Run

3-D Printed Wheelchair Helps Two-Legged Dog Learn to Run

Buzz60 (Jan. 29, 2015) — 3-D printing helps another two-legged dog run around with his four-legged friends. Jen Markham (@jenmarkham) has the adorable video. Video provided by Buzz60
Powered by NewsLook.com
Dogs Bring on So Many Different Emotions in Their Human Best Friends

Dogs Bring on So Many Different Emotions in Their Human Best Friends

RightThisMinute (Jan. 28, 2015) — From new-puppy happy tears to helpful-grocery-carrying-dog laughter, our four-legged best friends can make us feel the entire spectrum of emotions. Video provided by RightThisMinute
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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