- 著者
- Tomoe Shimada Tomimasa Sunagawa Kiyosu Taniguchi Yuichiro Yahata Hajime Kamiya Kumi Ueno Yamamoto Yoshinori Yasui Nobuhiko Okabe
- 出版者
- 国立感染症研究所 Japanese Journal of Infectious Diseases 編集委員会
- 雑誌
- Japanese Journal of Infectious Diseases (ISSN:13446304)
- 巻号頁・発行日
- vol.68, no.2, pp.151-158, 2015 (Released:2015-03-23)
- 参考文献数
- 46
- 被引用文献数
- 1 7
This study reports the epidemiological characteristics of hospitalized cases of influenza A(H1N1)pdm09 infection analyzed on the basis of surveillance data collected from July 24, 2009, the date on which the hospital-based surveillance of influenza cases was implemented in Japan, to September 5, 2010. During the study period, 13,581 confirmed cases were reported. Among those cases with information regarding the reason for hospitalization, 39% were admitted to hospitals for non-therapeutic purposes such as medical observation and laboratory testing. The overall hospitalization rate was 5.8 cases per 100,000 population when cases hospitalized for non-therapeutic purposes were excluded. While those aged under 20 years accounted for over 85% of hospitalized cases, the largest proportion of fatal cases was observed in those aged over 65 years. The overall case fatality rate for all hospitalized cases was 1.5%. The year-round surveillance for hospitalized influenza-like illness cases was launched in 2011, and it was expected that this surveillance system could add value by monitoring changes in the epidemiological characteristics of hospitalized cases of seasonal influenza.
- 著者
- Tsuyoshi Ogata Yoshinao Yamazaki Nobuhiko Okabe Yosikazu Nakamura Masato Tashiro Noriko Nagata Shigeyuki Itamura Yoshinori Yasui Kazutoshi Nakashima Mikio Doi Youko Izumi Takashi Fujieda Shin'ichi Yamato Yuichi Kawada
- 出版者
- Japan Epidemiological Association
- 雑誌
- Journal of Epidemiology (ISSN:09175040)
- 巻号頁・発行日
- pp.0807040024, (Released:2008-07-07)
- 参考文献数
- 20
- 被引用文献数
- 28 30
Background: H5N2 avian influenza virus infection of humans has not been reported thus far. The first H5N2 avian influenza infection of poultry in Japan occurred in Ibaraki. Methods: The subjects were workers at 35 chicken farms in Ibaraki Prefecture, where the H5N2 virus or antibody was isolated from chickens. None of the subjects exhibited influenza symptoms. The H5N2-neutralizing antibody titers of the first and second paired sera samples were compared. To investigate the possible factors for this increase, the H5N2-neutralizing antibody titer (1:40 or more) was calculated for the second samples. A logistic regression analysis was performed to examine the association of these factors with H5N2-neutralizing antibody positivity. Results: We performed Wilcoxon matched-pairs signed-ranked test on data collected from 257 subjects, and determined that the H5N2 antibody titers of the second paired sera samples were significantly higher than those of the first samples (P < 0.001). The H5N2 antibody titers of paired sera of 13 subjects without a history of seasonal influenza vaccination within the previous 12 months increased 4-fold or more. The percentage of antibody positivity was 32% for subjects with a history of seasonal influenza vaccination (28% of all subjects) and 13% for those without a history of the same. The adjusted odds ratio of H5N2-neutralizing antibody positivity was 4.6 (95% confidence interval: 1.6-13.7) for those aged over 40 and 3.1 (95% confidence interval: 1.6-6.1) for those with a history of seasonal influenza vaccination within the previous 12 months. Conclusion: The results suggest that this may have been the first avian influenza H5N2 infection of poultry to affect humans. A history of seasonal influenza vaccination might be associated with H5N2-neutralizing antibody positivity.