In China, health authorities are still working to identify the virus behind a pneumonia outbreak in the central city of Wuhan.
Authorities said the number of cases has increased to 44, with 11 people in serious condition. Hong Kong has reported two more cases linked to the Wuhan flu, bringing the city's total cases to five.
Health officials have ruled out common respiratory diseases such as influenza and avian influenza.
They added that no obvious human-to-human transmission has been seen.