An indication of just how fast and easily the bird flu virus could spread between humans in crowded cities if it ever turns pandemic :
A single sneeze in a busy area can end up infecting 150 people with a cold in just five minutes, new research suggests.
An analysis of the germs unleashed from a single commuter's sneeze showed that within minutes they are being passed on via escalator handrails or seats on trains and underground carriages.
At the busiest stations, one sneeze not smothered by a tissue or handkerchief will provide enough germs to infect another 150 commuters.
Dr Roger Henderson, a specialist in colds and flu, investigated how germs released by a sneeze would spread.
A single sneeze expels 100,000 droplets of germs into the air at 90mph. Individual droplets get transferred to handles, rails and other areas frequently held or touched. Up to 10 per cent of all commuters will come into contact with an area infected by that one sneeze, Dr Henderson calculated.
In the busiest areas, such as underground station escalators, this amounts to about 150 people during rush hour, he said.