THREE people who returned here from Mexico yesterday have been ordered to stay home for seven days, in case they had picked up the new flu strain there.

Two of them are Singaporeans, while the third person is a foreigner who stays here, the Health Ministry (MOH) said yesterday.

The trio are the first to be served the home quarantine order - Singapore's latest defence against the new Influenza A (H1N1) strain that is on the verge of causing a worldwide pandemic.

Nobody here has been found to have contracted the new flu strain. But MOH raised the alert level here from yellow to orange last Thursday after the World Health Organisation sounded a phase five alert, just one step short of a pandemic.

Starting yesterday, those who fly here after having been in Mexico in the last seven days will be quarantined in their own homes or in government chalets. Certis Cisco officers will serve the order on them and install an electronic camera in their homes to ensure they stay indoors.

The officers will make random calls to those quarantined, who will have to turn on the camera and stand in front of it to show that they are at home.

They will also be given an oral thermometer and a mask to use at home, so that they can monitor their temperature and reduce the risk of spreading any virus to their family or household members.

Anyone who breaks quarantine may have to wear a location-tracking electronic tag or be detained in a hospital, MOH warned. They can be fined up to $10,000 and/or jailed for up to six months too.

Nobody was referred to the Communicable Disease Centre (CDC) - the designated centre for potential Influenza A (H1N1) cases - for screening yesterday.

Laboratory tests have cleared all 27 people who had developed flu symptoms and been to the affected countries in the seven days before falling ill.

Read the full story in Tuesday's edition of The Straits Times.