Bird Flu Mutations

Study finds key markers for bird flu change

WASHINGTON (Reuters) - Researchers have found some of the changes that a flu virus needs to become a deadly pandemic strain, and said on Tuesday the H5N1 avian influenza virus has so far made only a few of them.

They said their study can help scientists watch for the mutations most likely to make H5N1 a global threat.

David Finkelstein of St. Jude Children's Research Hospital in Memphis, Tennessee, and colleagues looked at H5N1 virus samples from people who had been infected.

They found none were anywhere near as mutated as flu viruses that caused the three most recent pandemics, notably the 1918 "Spanish flu" that killed millions worldwide.

Writing in the Journal of Virology, Finkelstein's team said they identified 32 clear-cut changes in influenza viruses that differentiated a human flu from a bird flu.

Even when H5N1 viruses infected people, each one had made one or two of these changes at the most, Finkelstein said.

"We think they need to get to 13 to be truly dangerous," Finkelstein said in a telephone interview. "We never saw anything that approached the 13 that we saw in the Spanish flu."


link to full article