BEIJING (REUTERS) - A new virus that has killed nine people is adapting and mutating, underscoring the challenges for health authorities in controlling the outbreak, a Chinese health official said on Wednesday (Jan 22).

The coronavirus originated from a market with illegal wildlife transactions, Mr Gao Fu, director-general of China's Centre for Disease Control and Prevention, told a news briefing.

He added that the authorities have since banned all wildlife trading in Wuhan and no poultry is allowed in and out of the city.

The virus, originating in the central city of Wuhan at the end of last year, has spread to Beijing and Shanghai, as well as outside mainland China to the United States, Thailand, South Korea, Japan, Hong Kong and Taiwan.

China also said it is taking more strict measures in hospitals to protect healthcare workers in the new coronavirus outbreak and will increase training for healthcare workers nationwide.

Jiao Yahui, an official from the country's health commission, said on Wednesday that infection of medical staff in the outbreak shows there are loopholes in treatment methods.