Analysis: Gene swapping makes new China bird flu a moving target

Health officers examine a pigeon for H7N9 at a poultry market in ChangshaBy Kate Kelland, Health and Science Correspondent LONDON (Reuters) – A new bird flu virus that has killed 13 people in China is still evolving, making it hard for scientists to predict how dangerous it might become. Influenza experts say the H7N9 strain is probably still swapping genes with other strains, seeking to select ones that might make it fitter. If it succeeds, the world could be facing the threat of a deadly flu pandemic. But it may also fail and just fizzle out. …