Bird Flu Genes Decoded; New Clue to How It Kills

Brian Handwerk
for National Geographic News
January 26, 2006

A bird-flu pandemic is unlikely until the virus becomes able to be passed from human to human, rather than from animal to human.

To decipher how that might happen, and why the influenza is so deadly in the first place, scientists have to understand how the virus is built. For this, they need lots of genetic data on the virus—and they just got a lot more.

Thanks to a new study, the available genetic information on bird flu has just doubled.

Scientists have created the first large-scale genomic analysis of the avian flu virus. In the process, they have spotted a new variation that could help reveal why some outbreaks—like the present H5N1 virus—are more deadly than others. (Watch video: The Next Killer Flu.)

"[We used] a collection of viruses that spans 30-plus years and was found on all of the major continents," said study co-author John Obenauer, a genetics analyst John Obenauer at St. Jude Children's Research Hospital in Memphis, Tennessee.

"It's a very broad survey of the bird-flu population that includes H5N1 but also all 25 of the known serotypes."

Serotypes are closely related microscopic life-forms.

The study, published in this week's issue of the journal Science, identified 2,196 new bird-flu genes and 169 new complete genomes.

The new abundance of genetic information will be available to other flu investigators worldwide.

"Very little is known about the diversity of the avian flu virus in nature," said Adolfo Garcia-Sastre, a microbiologist at New York's Mount Sinai School of Medicine.

"Obviously birds are the reservoir [for the virus], so without understanding the diversity in that reservoir, we can't understand the source of the viruses that can create pandemics," said Garcia-Sastre, who was not involved in the study.

"These efforts can be combined with efforts to sequence human [influenza] strains and other animal strains, so that we can learn what makes a virus a bird virus, or a human virus, or some other type of virus."

Continued on Next Page >>




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