The elderly man, dubbed a "super spreader," may have infected as many as 52 people, the government said.
Nurses and air-force paramedics at the main airport, armed with the power to quarantine, are now taking the temperature of all travelers from Hong Kong and China's Guangdong Province, the two areas hit hardest by SARS.
Sick-looking people from SARS-hit regions are already quizzed on their health while stepping into Singapore, and two women who had arrived from Hong Kong and China on Thursday are now quarantined as suspected SARS cases.
Also see stories:
Kids escape brunt of killer SARS
Top health official says nation worthy of WHO entry



