GENEVA, Feb 14 (Reuters) - A World Health Organization-led joint mission with China will start its outbreak investigation work this weekend and will focus on how the new coronavirus is spreading and the severity of the disease, the WHO’s director said on Friday.

The mission will also seek more details on how, where and when the more than 1,700 healthworkers infected so far contracted the new virus, WHO officials said.

“We expect the full team to touch down over the weekend,” WHO chief Tedros Adhanom Ghebreyesus told reporters at briefing.

“Particular attention will be paid to understanding transmission of the virus, the severity of disease and the impact of ongoing response measures.”

Chinese authorities reported 5,090 new cases in mainland China on Friday, including more than 120 deaths, taking the total number of infected to 63,851, and the number of deaths from the disease, now called COVID-19, to 1,380. (Reporting by Stephanie Nebehay in Geneva and Kate Kelland in London; Editing by Hugh Lawson)