Report: Bird flu from south China
http://www.cnn.com/2007/HEALTH/conditions/03/05/birdflu.origin.reut/index.html

Reuters News Service and CNN.com
POSTED: 10:28 p.m. EST, March 5, 2007

WASHINGTON — China’s southern Guangdong Province is the source of the
dangerous H5N1 avian flu virus, according to a genetic analysis of the
virus published on Monday.

And Guangdong appears to be the source of renewed waves of the H5N1
strain, which has killed or forced the destruction of hundreds of
millions of birds, the team at the University of California Irvine
reported.

"We show that the Chinese province of Guangdong is the source of
multiple H5N1 strains spreading at both regional and international
scales," the researchers wrote in their report, published in the
Proceedings of the National Academy of Sciences.

"It is probably still originating there and spreading," Walter Fitch, a
professor of ecology and evolutionary biology who worked on the study,
said in a telephone interview.

"If you can control the virus at its source, you can control it more
efficiently," Fitch added in a statement.

"With a road map of where the strain has migrated, you’re more likely to
isolate the strain that you should be using to make the vaccine."

Since 2003, H5N1 has spread to more than 50 countries as far away from
China as Nigeria and Britain. The real fear is that the virus could
mutate into a form that people can easily pass from one to another and
spark a pandemic.

So far it has infected 277 people and killed 167 of them, according to
the World Health Organization.

The researchers looked at samples of the virus taken from across China
and as far west as Russia. They also looked at the the genetic sequences
of virus samples placed in GenBank, a public access database of genetic
information.

‘Family tree’

Fitch’s team constructed a "family tree" for the virus, which mutates
quickly. They looked specifically at two proteins, called hemagglutinin
and neuraminidase, the "H" and "N" in a flu strain’s name.

They show the basic version of the virus is a form seen in Guangdong
again and again.

"It seems to be seeding multiple outbreaks both from within China and
elsewhere. That is the primary epicenter. Now there are secondary
epicenters, as well, that have caught on fire," said Robert Wallace, a
postdoctoral researcher who led the study.

The researchers’ maps show China’s northwest Qinghai Province to be
another source of bird flu’s spread.

The study has practical value, Wallace said in a telephone interview.
For instance, neighboring countries can carefully watch imports from
southern China and can make bird vaccines that match the Chinese strain
of H5N1.

"Certainly the Chinese can investigate what is going on in Guangdong and
if their (poultry) plants there contribute to those strains, they could
so something to intervene," Wallace added.

In contrast to China, the researchers found that Indochina — Thailand,
Cambodia and Vietnam — appeared to absorb strains of the virus. They
said H5N1 spreads there but does not spread from there to anywhere else.

Both Fitch and Wallace said the study demonstrates why it is important
for countries to share samples of the virus from within their borders
with the scientific community.