1.Genetic Structure in the Region Near the Sialidase Gens in Bacteroides fragilis.
Tomomi KUWAHARA ; Haruyuki NAKAYAMA ; Tomoya IWASA ; Suya OKAMOTO ; Yuuki TSUCHIHASHI ; Yoshinari OHNISHI
Journal of the Korean Society for Microbiology 2000;35(5):364-364
No Abstract Available.
Bacteroides fragilis*
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Bacteroides*
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Genetic Structures*
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Neuraminidase*
2.Replacement of SARS-CoV-2 strains with variants carrying N501Y and L452R mutations in Japan: an epidemiological surveillance assessment
Yusuke Kobayashi ; Takeshi Arashiro ; Miyako Otsuka ; Yuuki Tsuchihashi ; Takuri Takahashi ; Yuzo Arima ; Yura K. Ko ; Kanako Otani ; Masato Yamauchi ; Taro Kamigaki ; Tomoko Morita-Ishihara ; Hiromizu Takahashi ; Sana Uchikoba ; Michitsugu Shimatani ; Nozomi Takeshita ; Motoi Suzuki ; Makoto Ohnishi
Western Pacific Surveillance and Response 2022;13(3):41-50
Objective:
Monitoring the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is important due to concerns regarding infectivity, transmissibility, immune evasion and disease severity. We evaluated the temporal and regional replacement of previous SARS-CoV-2 variants by the emergent strains, Alpha and Delta.
Methods:
We obtained the results of polymerase chain reaction screening tests for variants conducted in multiple commercial laboratories. Assuming that all previous strains would be replaced by one variant, the new variant detection rate was estimated by fitting a logistic growth model. We estimated the transmission advantage of each new variant over the pre-existing virus strains.
Results:
The variant with the N501Y mutation was first identified in the Kinki region in early February 2021, and by early May, it had replaced more than 90% of the previous strains. The variant with the L452R mutation was first detected in the Kanto-Koshin region in mid-May, and by early August, it comprised more than 90% of the circulating strains. Compared with pre-existing strains, the variant with the N501Y mutation showed transmission advantages of 48.2% and 40.3% in the Kanto-Koshin and Kinki regions, respectively, while the variant with the L452R mutation showed transmission advantages of 60.1% and 71.9%, respectively.
Discussion
In Japan, Alpha and Delta variants displayed regional differences in the replacement timing and their relative transmission advantages. Our method is efficient in monitoring and estimating changes in the proportion of variant strains in a timely manner in each region.
3.Letter to the Editor: Pathogens detected from patients with acute respiratory infections negative for SARS-CoV-2, Saitama, Japan, 2020
Yuzo Arima ; Yuuki Tsuchihashi ; Osamu Takahara ; Reiko Shimbashi ; Takeshi Arashiro ; Ayu Kasamatsu ; Yusuke Kobayashi ; Katsuhiro Komase ; Takuri Takahashi ; Kanako Otani ; Fangyu Yan ; Taro Kamigaki ; Kiyosu Taniguchi ; Motoi Suzuki
Western Pacific Surveillance and Response 2024;15(1):78-79
Utilizing data presented in the article by Miyashita et al., we illustrate the importance of testing data when assessing surveillance data. Accounting for the number of tests (denominator) and positivity (proportion of tests positive for a specific pathogen(s)) improves data interpretation in ways not possible from numerator case data alone.