Scientists believe they may have discovered a reason why the deadly H5N1 bird flu virus cannot yet jump easily between humans. Flu viruses which target man tend to attach to cells further up the airway – maximising their chances of being passed on by coughing or sneezing. Researchers found the bird flu virus attached itself to cells deep down in the human airways. The University of Wisconsin research is published in the journal Nature. The H5N1 strain of bird flu has spread across Europe, Africa and parts of Asia, has killed more than 100 people worldwide and infected about 180 since it re-emerged in 2003. But it still cannot jump easily from human to human. Scientists fear that if it gains that ability and mutates it could result in a human flu pandemic, with millions of deaths world-wide. Target molecule The Wisconsin team investigated why the virus could not spread easily between humans despite the fact that it could replicate efficiently in human lungs. Flu viruses infecting humans and birds are known to home in on slightly different versions of the same molecule, found on the surface of cells which line […]