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Experiment with influenza virus that still finds surprises
Tuesday February 23, 2010 18:03 EDT
By Maggie Fox
WASHINGTON (Reuters) -- Researchers mixed bird flu virus and created three new flu strains, a reminder that influenza viruses can exchange genes to create dangerous offspring.
His experiment, reported in Proceedings of the National Academy of Sciences, shows that while the avian H1N1 begins to wane, other forms of flu are in circulation and could emerge unexpectedly.
An expert committee of the World Health Organization met Tuesday to decide whether the H1N1 flu pandemic peaked. However, experts agree that the so-called swine flu could change again in a different form or recombine with another strain of influenza.
Meanwhile, the H5N1 avian influenza remains in circulation and has infected 478 people and killed 286 of them in Asia since its resurgence in 2003.
That particular strain afraid to influenza experts due to its high mortality when does infect humans. The experts worry that H5N1 could mutate or regroup with another strain of bird to facilitate transmission between people.
Yoshihiro Kawaoka of the University of Wisconsin-Madison and his colleagues are mixtures of H5N1 with the common strain H3N2 that is circulating.
Researchers still do not understand all the factors that cause the flu is so virulent and causes disease is transmitted so easily.
Therefore, Kawaoka's team tested exchange genes, reviewing whether it could create a strain of influenza with the deadly H5N1 properties and the ability to transfer between people of the H3N2.
The researchers generated 254 new strains of influenza and found that a mutation of H3N2 strain first isolated in Tokyo gave the virus the ability to easily infect.
Tests done on mice showed that 22 strains were more pathogenic than the seasonal H3N2 viruses, resulting in disease that could cause more efficiently.
Furthermore, the mice used in the tests, three were more virulent, which means that caused death more easily.
(Editing by Alan Elsner Spanish)