Swine flu: serious, but no panic yet
Updated on 28 April 2009
The World Health Organisation says the international swine flu outbreak can no longer be contained and is spreading fast, but it is not yet a full pandemic.
One hundred and fifty two people have died from the disease, all of them in Mexico where it started.
The two confirmed cases in Britain, a Scottish couple who had just returned from honeymoon in Mexico, are still in an isolation ward but are recovering.
The government has told people not to travel to Mexico unless it is essential, and most holiday charter flights have been cancelled.
Deadly flu?
Science correspondent Tom Clarke asks why the swine flu virus appears to have killed more than 150 people in Mexico but is no worse than normal flu anywhere else.
It is one of many questions that scientists in research labs around the world are trying to answer, working against the clock as the virus threatens to change and mutate as quickly as it spreads.
