The British government on Thursday officially launched a health campaign against swine flu after five cases of the disease were identified in the country.

"Catch it, Bin it, Kill it!" is the catch line of the campaign that includes a special telephone help line and health care advertisements on TV, radio and in the print media.

The public has been advised since the beginning of the week to wash their hands regularly, always carry tissues and use them to cover their mouths and noses when coughing and sneezing, and then dispose of the trash properly.

Alan Johnson, the secretary of state for health, said that leaflets giving health care advice would also be distributed to every home in Britain next Tuesday.

The five confirmed flu cases in Britain all were associated with travel to Mexico. The Foreign and Commonwealth Office is advising against all but essential trips to Mexico.

The Health Protection Agency, meanwhile, is advising anyone who becomes sick within seven days of returning from areas affected by the flu to stay at home and contact their doctor or the National Health Service.

The HPA is also enhancing its presence at airports in England to provide all passengers arriving from Mexico with information and advice on swine flu.

Johnson urged employers in Britain to review their business contingency plans to lessen the potential impact of the pandemic.

The World Health Organization late Wednesday raised its alert level to Phase 5, indicating a pandemic is imminent.

An announcement that a young girl in southwest England had contracted the virus dramatically increased concern about the disease amongst the general public in Britain.

Serious worries

On Wednesday, three more cases were confirmed in Britain. One of those who tested positive was a 12-year-old girl who had traveled on the same plane as two people currently being treated in Scotland.

Two adults -- a 22-year-old man and a 44-year-old woman from Birmingham -- also tested positive for the virus.

The girl from Torbay in Devon was being treated at home. Many of the students at her school did not learn of the case until about two hours after it was announced in the British parliament. The delay angered many parents and some pupils who said they should have been informed earlier.

The school has been shut for seven days as a precaution and antiviral drugs have been given to 230 pupils. Fifty of the students who came into close contact with the girl are being carefully monitored, the HPA said.

Those infected so far in Britain all show a direct connection with Mexico, and there was no immediate sign of a human to human transmission in the country. Still, the government said it is keeping a close eye on developments.

On a more positive note, seven people who had been closely monitored after showing flu-like symptoms after coming into contact with the Scottish couple, who were the first two positive cases in Britain, were declared infection free on Wednesday.