The World Health Organization has declared the swine flu situation a phase 5 alert after consulting with flu experts from around the world. They believe that a global outbreak of the disease is about to happen.

Global health authorities warned that swine flu was threatening to bloom into a plague, and are desperately trying to produce a vaccine against the virus. "All countries should immediately now activate their pandemic preparedness plans," WHO Director Margaret Chan told reporters in Geneva. "It really is all of humanity that is under threat in a pandemic."

A phase 5 alert means there is sustained transmission among people in at least two countries. If the virus starts to appear in different regions of the world, a full pandemic outbreak - phase 6 - will be declared, meaning a global plague of the deadly disease.