How did coronavirus cases aboard Diamond Princess spike so quickly?

The number of confirmed infections on the quarantined cruise ship docked in Yokohama, Japan jumped by at least 65, raising the total number to 135. But how did it reach that number so quickly? CGTN's Li Dongning asked Sanjaya Senanayake, an associate professor of medicine at the Australian National University specializing in infectious diseases, about the surge in cases.