Background: A cruise ship, named the Diamond Princess, had travel that originated in Yokohama on 20 January and included stops in Japan (Kagoshima), Hong Kong, Vietnam, Taiwan and Japan (Okinawa), before arriving back in Yokohama on 3 February. During this time, a passenger who disembarked on 25 January in Hong Kong, has presented with cough since 19 23 Jan and was confirmed positive for Novel cor