*** FORUMS ARCHIVE ***

We saw this one coming...

original article

NEW YORK (Reuters) - The H5N1 bird flu virus has mutated to infect
people more easily, although it still has not transformed into a
pandemic strain, researchers said on Thursday.

The changes are worrying, said Dr. Yoshihiro Kawaoka of the
University of Wisconsin-Madison.

"We have identified a specific change that could make bird flu grow
in the upper respiratory tract of humans," said Kawaoka, who led the
study.

"The viruses that are circulating in Africa and Europe are the ones
closest to becoming a human virus," Kawaoka said.

Recent samples of virus taken from birds in Africa and Europe all
carry the mutation, Kawaoka and colleagues report in the Public
Library of Science journal PLoS Pathogens.

"I don't like to scare the public, because they cannot do very much.
But at the same time it is important to the scientific community to
understand what is happening," Kawaoka said in a telephone interview.

The H5N1 avian flu virus, which mostly infects birds, has since 2003
infected 329 people in 12 countries, killing 201 of them. It very
rarely passes from one person to another, but if it acquires the
ability to do so easily, it likely will cause a global epidemic

All flu viruses evolve constantly and scientists have some ideas
about what mutations are needed to change a virus from one that
infects birds easily to one more comfortable in humans.

Birds usually have a body temperature of 106 degrees F, and humans
are 98.6 degrees F usually. The human nose and throat, where flu
viruses usually enter, is usually around 91.4 degrees F.

"So usually the bird flu doesn't grow well in the nose or throat of
humans," Kawaoka said. This particular mutation allows H5N1 to live
well in the cooler temperatures of the human upper respiratory tract.

H5N1 caused its first mass die-off among wild waterfowl in 2005 at
Qinghai Lake in central China, where hundreds of thousands of
migratory birds congregate.


That strain of the virus was carried across Asia to Africa and
Europe by migrating birds. Its descendants carry the mutation,
Kawaoka said.

"So the viruses circulating in Europe and Africa, they all have this
mutation. So they are the ones that are closer to human-like flu,"
Kawaoka said.

Luckily, they do not carry other mutations, he said.

"Clearly there are more mutations that are needed. We don't know how
many mutations are needed for them to become pandemic strains."