A woman and her three-year-old son were diagnosed last Friday, while a family of three - a couple and their 16-year-old daughter, who is a student of Bedok North Secondary School - were confirmed with H1N1 on Saturday. The sixth in the group, a 17-year-old girl from Raffles Junior College (RJC), was also diagnosed on Saturday. There were a total of 13 new cases diagnosed over the weekend, bringing the total now to 40. All except one were imported, and had histories of travel.

It is not known if the six patients who went to the wedding in Melbourne knew each other, but five of the six came back on the same flight on Tuesday. Four of them were sitting within four rows of each other, but the fifth was about 30 rows away.

The 16-year-old daughter of the couple returned on the same day but on a different flight. Both she and her father had some symptoms before they boarded their separate flights, while the woman with the toddler became unwell on board.

A Health Ministry (MOH) statement reminded travellers from infected areas to refrain from travelling if they have symptoms within 24 hours of their planned departure. 'This is to avoid infecting other passengers and putting them to great inconvenience if they have to be quarantined,' the statement said.

None of the six patients from the Melbourne wedding had a fever when they passed through the thermal scanners at the airport, and were not picked up.

In the next few days before they were diagnosed, they continued with their normal activities, with both girls spending some time in school or with friends.

Contact tracing is still being carried out for four of the patients who went to the Melbourne wedding.

The Education Ministry has advised schools to step up vigilance in monitoring students who participate in holiday activities in school. Temperature taking will be conducted during these activities.

A MOH spokesman said parents should monitor their children's health carefully. Parents should not send their children to school if they are unwell, especially if they had returned from affected countries recently.

Read the full report in Monday's edition of the Straits Times.

nicy@sph.com.sg

Additional reporting by Goh Yi Han