They push people to get vaccinated before they catch the flu, and individuals with health issues who might be more vulnerable can take extra precautions.

CNN: Tracking the flu with technology and Twitter

Chief Medical Officer for Wales Dr Tony Jewell said up to 30% of the population could catch swine flu over the next 12-18 months.

BBC: Wales opting out of flu service

The Chief Medical Officer for Wales, Dr Tony Jewell, estimated that up to 30% of the population could catch swine flu at some point over the next 12-18 months.

BBC: More call handlers for swine flu

The catch, Canadian officials say, is that the animals may have caught the flu from a human.

CNN: Canada: Farmer possibly gave swine flu to pigs

Mr Lansley told MPs that he had decided to re-instate the "Catch it, Bin it, Kill it" advertising campaign, which aims to limit the spread of flu.

BBC: Government accused of 'misjudgement' over flu outbreak