Bird flu virus 'now in two forms'
"Back in 2003 we only had one genetically distinct population of H5N1 with the potential to cause a human pandemic. Now we have two"
"The virus is still a bird virus, it is not yet a human virus, and it may never be a human virus"
"But no need to panic. As long as we manage to keep it reasonably under control in the birds I think we can breathe relatively easily for at least a year or two."