著者

Kenichi Komabayashi Junji Seto Yohei Matoba Yoko Aoki Shizuka Tanaka Tatsuya Ikeda Yoko Matsuzaki Tsutomu Itagaki 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.2020.525, (Released:2020-08-01)

参考文献数

10

被引用文献数

1 18

著者

Kenichi Komabayashi Junji Seto Shizuka Tanaka Yu Suzuki Tatsuya Ikeda Noriko Onuki Keiko Yamada Tadayuki Ahiko Hitoshi Ishikawa 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.71, no.6, pp.413-418, 2018-11-30 (Released:2018-11-22)

参考文献数

26

被引用文献数

28 35

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The incidence of modified measles (M-Me), characterized by milder symptoms than those of typical measles (T-Me), has been increasing in Japan. However, the outbreak dominated by M-Me cases has not been thoroughly investigated worldwide. The largest importation-related outbreak of measles with genotype D8 occurred in Yamagata Prefecture, Japan, from March to April 2017. This phenomenon was observed after Japan had achieved measles elimination in 2015. We confirmed 60 cases by detecting the genome of the measles virus (MeV). Among the cases, 38 were M-Me and 22 were T-Me. Thirty-nine (65.0%) patients were 20–39 years of age. Three out of 7 primary cases produced 50 transmissions, of which each patient caused 9–25 transmissions. These patients were 22–31 years old and were not vaccinated. Moreover, they developed T-Me and kept contact with the public during their symptomatic periods. Considering that M-Me is generally caused by vaccine failure, some individuals in Japan may have insufficient immunity for MeV. Accordingly, additional doses of measles vaccine may be necessary in preventing measles importation and endemicity among individuals aged 20–39 years. Furthermore, to accurately and promptly diagnose individuals with measles, particularly those who can be considered as primary cases, efforts must be exerted to detect all measles cases using epidemiological and genetic approaches in countries where measles elimination had been achieved.

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

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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

Kenichi Komabayashi Junji Seto Yohei Matoba Yoko Aoki Shizuka Tanaka Tatsuya Ikeda Yoko Matsuzaki Tsutomu Itagaki 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

vol.73, no.5, pp.394-397, 2020-09-30 (Released:2020-09-24)

参考文献数

10

被引用文献数

2 18

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 6

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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.

著者

Katsumi Mizuta Waka Tanaka Kenichi Komabayashi Shizuka Tanaka Junji Seto Yoko Aoki Tatsuya Ikeda

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

vol.72, no.4, pp.211-223, 2019 (Released:2019-07-24)

参考文献数

102

被引用文献数

12 10

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We introduced a microplate method for virus isolation in the Department of Microbiology, Yamagata Prefectural Institute of Public Health (YPIPH) in 1999 in Yamagata, Japan. We have since carried out longitudinal epidemiological studies on viral infectious diseases, particularly respiratory viruses, combining traditional technologies such as virus isolation and serological techniques and newly developed molecular methods. Here, we provide an overview of our activities at YPIPH between 1999 and 2018. During the study period, we observed emerging and re-merging diseases such as those caused by echovirus type 13, enterovirus D68, parechovirus-A3 (PeV-A3), and Saffold virus. With regard to PeV-A3, we proposed a new disease concept, “PeV-A3-associated myalgia/myositis.” We also revealed the longitudinal epidemiologies of several viruses such as enterovirus A71 and coxsackievirus A16. To perform longitudinal epidemiological studies at any time in Yamagata, we established a system for stocking clinical specimens, viral isolates, complementary DNAs, and serum specimens. We have also pursued collaboration works with virology laboratories across Japan. We hope our experiences, findings, and research materials will further contribute to the development of countermeasures against viral infectious diseases and improvement in public health strategies in Yamagata, Japan, Asia, and around the world.