An outbreak of highly pathogenic avian influenza A H5N1was first officially reported from South Korea in mid-December 2003. Since then outbreaks of avian influenza have been reported throughout Asia during 2004 and into 2005. The outbreak has resulted in the death or culling of more than 100 million poultry throughout Asia.The number of cases among humans is also rising since the strain emerged in South-East Asia in 2003 before spreading to Europe and Africa.The virus was found in migratory birds. Scientists fear it may be carried by migrating birds to Europe and Africa but say it is hard to prove a direct link with bird migration.

The first outbreaks in the European Union were recorded in January 2006 when cases were confirmed in wild swans in Italy, Greece, Germany and Austria. Within weeks, cases were also confirmed in Slovenia, Slovakia, Hungary, and France, where mass vaccination of ducks and geese on farms was carried out.

Millions of birds have died or been destroyed as a result of outbreaks of the deadly H5N1 strain as far apart as northern Europe and the Far East.

The first human deaths from H5N1 outside Asia, in January 2006, heightened concern about the spread of the disease, but the World Health Organization pointed out that the deaths, in Turkey, were among people who had been in close contact with infected birds, and were not passed from human to human. And although a cluster of deaths in Indonesia in 2006 sparked renewed fears about transmission between humans, the WHO maintained there was no evidence of sustained spread from person to person, and scientists do not believe it is mutating into a version that spreads more easily among humans.

By the end of 2007 a total of 14 countries had suffered human cases, with Burma and Pakistan added to the list in the last few weeks of the year. Although the number of new human cases fell in 2007 to its lowest number for three years, the mortality rate continued to rise, topping 60% by the end of the year. The 300th human case was confirmed in the spring and the 200th death occurred in September 2007. In June 2007 Indonesia became the first country to have 100 confirmed cases of H5N1 among humans.

By 2008, Bird flu continues to hold much of the globe in its lethal grip. Several nations in Europe and Asia are reporting new cases of the lethal H5N1 bird flu strain among poultry, sparking new fears that humans could be at risk. India, Bangladesh,China , Romania and Hungary are already reportedly infected with avian flu. In Thailand, a man has died of bird flu, raising the country's death toll from the virus to 13. Hungary says it has developed a new vaccine that appears to protect humans and animals against the virus.

BBC has drawn a map, timelining the outbreak of bird flu around the world since the first time in 2003-04.