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

Yoko Aoki Katsumi Mizuta Tatsuya Ikeda Chieko Abiko Tsutomu Itagaki Tadayuki Ahiko

出版者

Tohoku University Medical Press

雑誌

The Tohoku Journal of Experimental Medicine (ISSN:00408727)

巻号頁・発行日

vol.230, no.2, pp.111-115, 2013 (Released:2013-06-20)

参考文献数

7

被引用文献数

5 6

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The measles elimination project led by the World Health Organization (WHO) has been moving toward the target of eliminating measles in the WHO Western Pacific Region. In Japan, prefectural public health institutes play a key role for the laboratory diagnosis of measles virus (MV) infection, which is based on PCR, virus isolation, and genotyping. Microscopic examination of viral-sensitive cell lines during routine virus isolation from nasopharyngeal specimens has been used to detect the morphological changes typical for the growth of respiratory viruses. Here, we describe the unexpected isolation of vaccine-derived MVs from the two unrelated 1-year-old boys with acute respiratory infection. The nasopharyngeal specimens were obtained from one patient in February 2007 and from another in December 2012. Incidentally, the two children had received measles-rubella vaccination 9 or 11 days before the sampling. The isolates from two children induced morphological changes of the viral-sensitive cell lines, such as syncythia formation (cell fusion). We finally identified the isolates as vaccine-derived MVs by sequence analysis and immunological methods with anti-measles nucleoprotein antibodies. As no typical symptoms of MV infection were observed in either patient, the vaccine-derived MVs were isolated not as causative pathogens but by chance. In fact, there was no suspected case of secondary MV infection in either patient, thereby excluding the possibility that vaccine-derived MVs spread from human to human. Our experiences suggest the possibility of vaccine-derived MV isolation by cell cultures and the difficulty in identifying MVs in specimens from patients other than clinically suspected measles cases.

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.