Another two people here have been confirmed to have the Wuhan virus, bringing the total to three, the Ministry of Health (MOH) said yesterday as it stressed that all measures will be taken to contain possible spread to the community.
The first confirmed case was a 66-year-old man from Wuhan who is here on holiday. He is at the Singapore General Hospital (SGH) and his condition is stable.
His 37-year-old son, who was travelling with him, has since been confirmed to have the virus. He, too, is at SGH and in a stable condition.
Another Chinese tourist - a 53-year-old woman from Wuhan who came here separately from the two men - has been confirmed as having the virus. She is warded at the National Centre for Infectious Diseases and her condition is also stable.
At a briefing, the third in three days, the ministry said that as of noon yesterday, there were a total of 44 suspected cases with patients aged between one and 78.
Of these, 13 have tested negative for the Wuhan virus, and three are confirmed.
Contact tracing has started to identify close contacts of the three. Close contacts will be quarantined and monitored for symptoms for 14 days from their last exposure with the patient.
But more imported cases are expected, given the large number of cases in China and the high travel volume from China to Singapore.
On the first confirmed case, officials said they have identified 46 people who had close contact with the man, who arrived on a China Southern Airlines flight on Monday.
Twenty-four of them have left Singapore. They include a group of eight who, according to Malaysia's The Star newspaper, are being isolated and monitored by health officers at a hotel in Johor Baru for symptoms related to the virus.
Malaysia's Deputy Health Minister Lee Boon Chye said yesterday: "They are not patients. They are just being observed in case they develop any symptoms."
Of the remaining 22 who had close contact with the man, 17 have been contacted, including the man's son warded at SGH. The 16 others will be quarantined and monitored for the development of symptoms for 14 days from the last exposure to the patient.
On the 53-year-old woman, health officials said she developed a fever less than 24 hours after she arrived on a Scoot flight on Tuesday. She went to Raffles Hospital and was sent to Tan Tock Seng Hospital's emergency department.
She came to Singapore with one travel companion and they were staying at J8 hotel in Townshend Road. Before she fell ill, she visited the Orchard area, Marina Bay Sands and Gardens by the Bay. She took public transport to these places.
Associate Professor Vernon Lee, director of communicable diseases at MOH, said close contacts are people "who are within about 2m and spend a reasonable prolonged period of time, about 30 minutes or more, with the individual".
The second tier, who are at moderate risk, are people with some contact - but neither close nor prolonged, such as encounters at public places or hotel check-in.
Of the first case, 13 people have been identified as secondary contacts. Eight have been contacted and are under phone surveillance to ensure that they remain well.
The ministry is also tracing passengers on the same flights as the three confirmed cases. But Prof Lee stressed that the woman, like the two men, was not sick during the flight, and is unlikely to have spread the virus then.
The number of cases has been rising internationally, with 26 deaths, all in China, reported so far.
The World Health Organisation, after an emergency meeting, has decided it is too early to declare the Wuhan virus a "public health emergency of international concern", since the extent of human-to-human transmission is still unclear.
• Additional reporting by Timothy Goh and Aw Cheng Wei