The virus outbreak in China continues with unabated force. China announces that more than 1,700 new cases have been confirmed since Monday, which means that more than 4,500 people have been infected.

The number of deaths has risen from 81 to 106.

The World Health Organization (WHO) says in a report that the incubation time of the virus is between two and ten days.

More information is needed

The WHO cannot confirm Chinese data that infected people can spread the disease before symptoms occur.

"Detailed epidemiological information from more people infected is needed to determine the infection period of 2019ncov, especially if transmission can be from symptom-free individuals or during the incubation period," WHO writes in a statement.