"Tests have not found any explicit evidence of the virus' human-to-human transmission at the moment. The possibility of human-to-human transmission is not ruled out but the risk of human-to-human transmission is relatively low," the authorities said in a statement.

Among 41 confirmed cases, there are members of the same family: a husband, who worked at a local seafood market — the suspected hotbed of the virus — and then a wife, who refuted visiting the market.

On Tuesday, Maria Van Kerkhove, acting head of the World Health Organization's emerging diseases unit, said that the virus could have limited human-to-human transmission but spread fast.

The unknown kind of viral pneumonia was reported from Wuhan in early January. The infected individuals reportedly display symptoms typical of pneumonia and other acute respiratory diseases. It prompted fears on the Internet that the nation might be experiencing a return of the SARS, an epidemic that had claimed more than 600 lives in China throughout 2002-2003.

Last week, the epidemic was confirmed to be a new type of coronavirus. On Saturday, China confirmed the first lethal case in Wuhan.