Researchers track movement of bird flu

Researchers have been tracking the bird flu virus in the hope of a breakthrough for future vaccine development.

A team from the World Health Organisation's (WHO) Global Influenza Surveillance Network has studied 13,000 flu samples, from between 2002 and 2007, from around the world.

It tracked the locations where different strains of the virus occurred and used the information to create an antigen map, allowing the team to determine the migration pattern of the virus.

It found that the virus's breeding grounds are in Asia and new varieties of the virus evolve in that area before being spread by travellers to Europe, Australia and North America and finally to South America, where they die away.

Derek Smith, author of the study, said that Asia is the best place to look for up-and-coming strains.

"In order to try to predict how flu viruses might evolve, we have to understand how they're moving around the world and where they're evolving," he explained.

WHO estimates that there have been 382 cases of laboratory-confirmed cases of bird flu since 2003, with 241 deaths from the virus.