Key bird flu process identified
Bird flu - H5N1 virus - can spread to humans
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Friday, 05, Oct 2007 04:15
Scientists have identified a key stage in how the H5N1 avian flu virus is able to affect humans and spread amongst them.
This stage must take place for the virus to be easily able to transmit from person to person, according to the study.
Since it first emerged in Hong Kong in 1997, the H5N1 virus has been slowly evolving into a pathogen (infectious agent) that is better equipped to infect humans.
Bird flu first arises in chickens and other birds but other animals and humans that come into contact with the birds can become infected.
Writing in the Public Library of Science Pathogens, researchers from the University of Wisconsin-Madison argue that over time the avian virus may be able to change genetically and spread easily.
In tests on mice they identified a single change in a viral surface protein that enabled the virus to settle in the respiratory system.
"[This] may provide a platform for the adaptation of avian H5N1 viruses to humans and for efficient person-to-person virus transmission," the researchers argue.
By settling in the respiratory system transmission is made easier through coughs and sneezes.
The researchers concluded that the stage they identified is "needed, but not sufficient" for H5N1 to spread.
"There are other viral factors needed to cause a viral pandemic [of bird flu]."
More than 250 human H5N1 human infections worldwide have been reported, with more than 150 cases proving fatal.