Transmission routes of Covid-19 virus in the Diamond Princess Cruise ship

Pengcheng Xu; Hua Qian; Te Miao; Hui-ling Yen; Hongwei Tan; Benjamin J. Cowling; Yuguo J Li

In general, a cruise ship in a voyage is like a small town or community. As the passengers and crew sleep, eat and play, a cruise ship is probably one of the most crowded 24 hr humanmade public communities. Large outbreaks of norovirus were frequently reported in cruise ships (CDC, 2020a) . Cruise ships may be considered as a place integrating all possible crowded indoor environments on landrestaurant, swimming pool, casino, theatre, bars, food streets, hotels, etc. For the Diamond Princess Cruise ship during its voyage, all these onboard public spaces were open to all passengers on Jan 20-Feb 4, but suddenly closed when the Japanese Government implemented the 14-day quarantine from 7 am, Feb 5. During the quarantine period, passengers stayed in their rooms, and the outer cabins had access to balcony doors. The transmission routes of the virus may be pinpointed by examining who were infected before and during the quarantine period. For example, as passengers stayed in their individual staterooms, transmission by the recirculating central air conditioning systems may be implied if there were cross-room transmission between passengers.