A human influenza pandemic sparked by the deadly Asian strain of bird flu could cost industrialised nations more than 465 billion euros. That is according to a report from the World Bank, which is due to be presented at a major conference in Geneva today.Health experts are drawing up a battle plan to combat the threat of bird flu and to try to prevent it developing into a pandemic. Maker of the influenza drug Tamiflu, Roche, says it has raised production and is on course to continue doing so. At least 62 people have died from the H5N1 strain of avian flu in Asia since 2003, and cases in birds have been seen in eastern Europe over recent weeks. The fear is that the virus could mutate into a strain that could pass easily from human to human. In China, six million birds have been culled in a province hit by the disease. The move came as investigations continued into whether three Chinese people have contracted bird flu, one of whom – a 12-year-old girl – has died.