Nakamura Naomi, Arima Yuzo, Shimada Tomoe, Matsui Tamano, Tada Yuki, Okabe Nobuhiko
Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan . ; Division of Quarantine and Sanitation, Chubu Airport Quarantine Branch, Nagoya Quarantine Station, Aichi, Japan .
Western Pac Surveill Response J. 2012 Jun 8;3(2):39-45. doi: 10.5365/WPSAR.2011.2.3.002. Print 2012 Apr.
Dengue continues to be a global public health concern. In Japan, although dengue cases are currently seen only among travellers returning from endemic areas, the number of reported cases is rising according to the national case-based surveillance system. We evaluated the characteristics of dengue cases imported into Japan and the relationship between the incidence of infection and season of travel to popular destinations.
Dengue cases reported to the national surveillance system were retrospectively examined. The number of reported cases per number of Japanese travellers to a dengue-endemic country was calculated to estimate the country-specific incidence of imported dengue virus infection. The incidence of dengue infection among Japanese travellers was compared between dengue high season and low season in each country using relative risk (RR) and associated 95% confidence intervals (CI).
Among 540 Japanese residents who were reported as dengue cases from 2006 to 2010, the majority had travelled to Indonesia, India, the Philippines and Thailand. The RR of dengue infection among Japanese travellers during dengue high season versus low season was 4.92 (95% CI: 3.01-8.04) for the Philippines, 2.76 (95% CI: 1.67-4.54) for Thailand and 0.37 (95% CI: 0.15-0.92) for Indonesia.
Overall, higher incidence of imported cases appeared to be related to historic dengue high seasons. Travellers planning to visit dengue-endemic countries should be aware of historic dengue seasonality and the current dengue situation.
登革热仍是全球公共卫生关注的问题。在日本，尽管目前登革热病例仅出现在从流行地区返回的旅行者中，但根据国家病例监测系统，报告的病例数正在上升。我们评估了输入日本的登革热病例的特征，以及感染发生率与前往热门目的地旅行季节之间的关系。
对向国家监测系统报告的登革热病例进行回顾性检查。计算前往登革热流行国家的日本旅行者中每报告病例数，以估计特定国家输入登革热病毒感染的发生率。使用相对风险（RR）和相关的95%置信区间（CI），比较每个国家登革热高发季节和低发季节日本旅行者中登革热感染的发生率。
在2006年至2010年报告为登革热病例的540名日本居民中，大多数人前往了印度尼西亚、印度、菲律宾和泰国。菲律宾登革热高发季节与低发季节相比，日本旅行者登革热感染的RR为4.92（95%CI：3.01-8.04），泰国为2.76（95%CI：1.67-4.54），印度尼西亚为0.37（95%CI：0.15-0.92）。
总体而言，输入病例较高的发生率似乎与历史上的登革热高发季节有关。计划前往登革热流行国家的旅行者应了解历史上的登革热季节性和当前的登革热情况。
