A team of scientists at the University of California, Irvine, who have been conducting a genetic analysis of the H5N1 bird flu virus, have found that China's southern Guangdong Province is the source of the deadly strain.
The researchers say the multiple H5N1 strains spreading at both regional and international levels originated in the Chinese province of Guangdong, which also appears to be the source of renewed waves of the H5N1 strain.
Walter Fitch, a professor of ecology and evolutionary biology who worked on the study, has reportedly said the virus is probably still originating there and still spreading.
Fitch says if the virus is controlled at its source, it can be controlled more efficiently, and a 'road map' of where the strain has migrated, will make it easier to isolate the strain that is needed to make a vaccine.
Since 2003, H5N1 has spread globally and reached more than 50 countries as far away from China as Nigeria and Britain.
It has to date killed or forced the destruction of hundreds of millions of birds and killed 167 people.
The fear gripping scientists is that the virus will mutate into a form that can easily pass from person to person triggering a pandemic which could kill billions.
Fitch's team examined samples of the virus taken from across China and as far west as Russia and also looked at the genetic sequences of virus samples placed in GenBank, a public access database of genetic information.
They were able to construct a "family tree" for the virus, which mutates quickly by looking specifically at two proteins, called hemagglutinin and neuraminidase, the "H" and "N" in a flu strain's name.
Their results show the basic version of the virus is a form seen in Guangdong over and over again.
Robert Wallace, a postdoctoral researcher who led the study says the virus appears to be seeding multiple outbreaks both from within China and elsewhere and China is the primary epicenter.
Wallace says secondary epicenters now exist as well, that have 'caught on fire'.
The researchers say their maps show China's northwest Qinghai Province to be another source of bird flu's spread.