There has been “limited” human-to-human transmission of a new coronavirus that has struck the mainland city of Wuhan, mainly small clusters in families, but there is potential for wider spreading, the World Health Organisation (WHO) said on Tuesday.

A Chinese woman has been quarantined in Thailand with a mystery strain, authorities said on Monday, the first time it has been detected outside China.

In all, 41 cases of the virus – which is similar to Sars which killed 299 in Hong Kong in 2003 – have been reported in Wuhan, mainly through exposure at a seafood market. One person there has died.

Dr. Maria Van Kerkhove, acting head of the WHO’s emerging diseases unit, told a Geneva news briefing that the agency had given guidance to hospitals worldwide about infection control in case of spread, including by a “super-spreading” event in a health care setting.

“This is something on our radar, it is possible, we need to prepare ourselves,” she said.

Hong Kong health officials have put dozens of people in isolation in hospital since New Year's Eve over fears they have caught the virus following trips to Wuhan, with three new suspected cases just on Tuesday.

But the SAR authorities haven't announced any confirmed cases and although Taiwan, Singapore and South Korea have all reported suspected cases, no province on the mainland, other than Hubei, has reported any patients feared to have the virus. (Refinitiv, RTHK)