SINGAPORE'S 15th Influenza A (H1N1) case, a 39-year-old Indonesian woman, is also the first local case.

She had not been abroad recently. Her niece, who was the 11th confirmed H1N1 case here, was infected after returning from New York on June 1.

The woman had accompanied her niece to the doctor last Tuesday when the latter developed symptoms of the flu. Three of the woman's household members have been placed on home quarantine.

The Health Ministry also said last night it has tracked down 18 passengers who shared the same flight as the 13th case, a 23-year-old Singaporean man who travelled to Melbourne.

All 18 passengers have been placed under home quarantine.

There will not be any contact tracing follow-up for the Singapore Airlines stewardess, the 14th person here to come down with the virus, as she developed symptoms more than 24 hours after the flight.

In the case of the 12th patient, an 18-year-old male who had travelled by MRT to see a doctor, MOH said Singaporeans need not be alarmed as the train ride from Serangoon to Kovan lasted two minutes and there was limited exposure to other people.