- 著者
- Kenichi Komabayashi Yohei Matoba Junji Seto Yoko Ikeda Waka Tanaka Yoko Aoki Tatsuya Ikeda Yoko Matsuzaki Tsutomu Itagaki Kazuya Shirato Katsumi Mizuta
- 出版者
- National Institute of Infectious Diseases, Japanese Journal of Infectious Diseases Editorial Committee
- 雑誌
- Japanese Journal of Infectious Diseases (ISSN:13446304)
- 巻号頁・発行日
- pp.JJID.2020.776, (Released:2020-11-30)
- 参考文献数
- 31
- 被引用文献数
- 7
Isolation of seasonal coronaviruses, which include human coronavirus (HCoV) OC43, HCoV-HKU1, and HCoV-NL63, from primary cultures is difficult because it requires experienced handling, an exception being HCoV-229E, which can be isolated using cell lines such as RD-18S and HeLa-ACE2-TMPRSS2. We aimed to isolate seasonal CoVs in Yamagata, Japan to obtain infective virions useful for further research and to accelerate fundamental studies on HCoVs and SARS-CoV-2. Using modified air-liquid interface (ALI) culture of the normal human airway epithelium from earlier studies, we isolated 29 HCoVs (80.6%: 16, 6, 6, and 1 isolates of HCoV-OC43, HCoV-HKU1, HCoV-NL63, and HCoV-229E, respectively) from 36 cryopreserved nasopharyngeal specimens. In ALI cultures of HCoV-OC43 and HCoV-NL63, the harvested medium contained more than 1×104 genome copies/µL at every tested time point during the more than 100 days of culture. Four isolates of HCoV-NL63 were further subcultured and successfully propagated in an LLC-MK2 cell line. Our results suggest that ALI culture is useful for isolating seasonal CoVs and sustainably obtaining HCoV-OC43 and HCoV-NL63 virions. Furthermore, the LLC-MK2 cell line in combination with ALI cultures can be used for the large-scale culturing of HCoV-NL63. Further investigations are necessary to develop methods for culturing difficult-to-culture seasonal CoVs in cell lines.
- 著者
- Junji Seto Yoko Aoki Kenichi Komabayashi Yoko Ikeda Mika Sampei Naomi Ogawa Yumiko Uchiumi Shunji Fujii Masami Chiba Emiko Suzuki Tatsuya Takahashi Keiko Yamada Yoshiko Otani Yoshihiro Ashino Kyoko Araki Takeo Kato Hitoshi Ishikawa Tatsuya Ikeda Hideaki Abe Tadayuki Ahiko Katsumi Mizuta
- 出版者
- National Institute of Infectious Diseases
- 雑誌
- Japanese Journal of Infectious Diseases (ISSN:13446304)
- 巻号頁・発行日
- vol.74, no.6, pp.522-529, 2021-11-22 (Released:2021-11-22)
- 参考文献数
- 27
- 被引用文献数
- 2 5
Public health interventions have played an important role in controlling coronavirus disease 2019 (COVID-19), which is a rapidly spreading infectious disease. To contribute to future COVID-19 countermeasures, we aimed to verify the results of the countermeasures employed by public health centers (PHCs) against the first wave of COVID-19 in Yamagata Prefecture, Japan (Yamagata). Between January and May 2020, 1,253 patients suspected of SARS-CoV-2 infection were invited for testing. Simultaneously, based on retrospective contact tracings, PHCs investigated the infection sources and transmission routes of laboratory-confirmed COVID-19 cases and tested 928 contacts. Consequently, 69 cases were confirmed between March 31 and May 4, 58 of whom were from among the contacts (84.1%; 95% confidence interval [CI] 75.5–92.7). The spread of infection was triggered in cases harboring epidemiological links outside Yamagata. Subsequently, the number of cases rapidly increased. However, PHCs identified epidemiological links in 61 (88.4%; 95% CI 80.8–96.0) of the 69 cases, and transmission chains up to the fifth generation. Finally, the spread of infection ended after approximately one month. Our results indicate that the identification of infection sources and active case finding from contacts based on retrospective contact tracing was likely to be an effective strategy in ending the first wave of COVID-19 in Yamagata.