Haplotype networks of SARS-CoV-2 infections in the Diamond Princess cruise ship outbreak

Tsuyoshi Sekizuka; Kentaro Itokawa; Tsutomu Kageyama; Shinji Saito; Ikuyo Takayama; Hideki Asanuma; Nao Naganori; Rina Tanaka; Masanori Hashino; Takuri Takahashi; Hajime Kamiya; Takuya Yamagishi; Kensaku Kakimoto; Motoi Suzuki; Hideki Hasegawa; Takaji Wakita; Makoto Kuroda

An increased number of COVID-19 cases have been confirmed, and it is now difficult to identify infection routes because some Japanese cases have no recent travel history to China or contact with persons from Wuhan City or Hubei Province in China. Regarding the quarantine on the DP 15 cruise ship, the enclosed circumstances revealed how SARS-CoV-2 can be spread in the community. Further field epidemiological studies should be conducted to trace the link of infections but, unfortunately, efforts to identify the route of transmission are still limited. This study demonstrated that HN-GSNVs can contribute to epidemiologic field investigations and identified possible transmission routes in the DP cruise ship outbreak after the quarantine was laboratory testing. We thank Dr. Makoto Ohnishi and all the staff of the National Institute of Infectious Diseases, Field Epidemiology Training Program (FETP) team, the Ministry of Health, Labor and Welfare, and local governments for their assistance with administrative matters, field investigation, data collection, and laboratory testing. We would like to thank all the authors who have kindly deposited and shared genome data on GISAID. A table with genome sequence 35 acknowledgments can be found in Supplementary Table S3 . We would like to thank Editage (www.editage.com) for English language editing.