Abstract: Objective To analyze the epidemiological characteristics (temporal, spatial, and demographic distributions) of indigenous and imported cases of dengue fever reported in Chinese mainland from 2005 to 2020.Methods The seasonal characteristics of dengue fever were analyzed using Excel 2010. Trend analysis was performed on the annual median age of disease onset using the Mann-Kendall test with the use of R 4.0.2. The map visualization and spatial analysis of cases were conducted using ArcGIS 10.3 software.Results A total of 81 648 indigenous cases of dengue fever were reported in 14 provinces (autonomous regions or municipalities) of Chinese mainland from 2005 to 2020. The indigenous cases were reported between May and December, concentrated between August and November (98.26%), and were distributed south from 35°36?N, mainly in Guangdong (74.01%) and Yunnan (13.74%) provinces, indicating seasonal and regional characteristics. Two major outbreaks of dengue fever occurred in 2014 and 2019, with 46 033 and 15 376 indigenous cases, respectively, adding up to 75.21% of the total indigenous cases. Among the local cases from 2005 to 2020, the male-to-female ratio was 0.99∶1; 54.93% were aged between 25 and <55 years; the top three frequent occupations were engagement in housework or unemployment (21.40%), service workers (12.46%), and retirees (11.71%). The median age of the total indigenous cases was 40 years (interquartile range [IQR]: 27-54). The difference of overall trend of the median age of indigenous cases since 2005 was not statistically significant (Z=1.510, P=0.131). There were a total of 12 701 imported cases in 30 provinces (autonomous regions or municipalities) except the Tibet Autonomous Region in Chinese mainland from 2005 to 2020. The imported cases were reported throughout a year, frequently between June and November (81.81%), and were mainly distributed in Yunnan, Guangdong, Fujian, and Zhejiang provinces, suggesting seasonal and regional characteristics. The imported cases were mainly from Southeast Asian countries including Myanmar and Cambodia. In 2019, the number of imported cases reached a peak of 5 813, accounting for 45.77% of the total imported cases. Among the imported cases from 2005 to 2020, the male-to-female ratio was 2.05∶1; 73.29% were aged between 25 and 54 years; the top three frequent occupations were farmers (24.13%), service workers (19.34%), and engagement in housework or unemployment (13.91%). The median age of the total imported cases was 33 years (IQR: 26-44). The overall trend of the median age of imported cases since 2005 was not statistically different (Z=0.413, P=0.679). A total of 15 376 indigenous cases and 5 813 imported cases reported in 2019, and the number of indigenous and imported cases reported were dramatically decreased to 616 and 158 in 2020, respectively.Conclusions Dengue fever outbreaks in Chinese mainland are still caused by imported cases, with significant seasonal and regional characteristics. The indigenous cases were mainly distributed in Guangdong and Yunnan provinces, while the imported cases were mainly from Southeast Asian countries including Myanmar and Cambodia. There was no significant change in the median age of dengue fever cases from 2005 to 2021.

Key words: Dengue fever, Epidemiological characteristic, Temporal distribution, Spatial distribution, Demographic distribution

摘要： 目的 分析2005－2020年中国大陆本地和输入性登革热病例的时间、空间和人群分布等流行病学特征。方法 采用Excel 2010软件分析登革热的季节性特征；采用R 4.0.2语言,基于Mann-Kendall趋势检验对登革热逐年发病年龄中位数开展趋势分析；通过ArcGIS 10.3软件实现病例的地图可视化,并开展空间分析。结果 2005－2020年中国14个省（自治区、直辖市）报告81 648例登革热本地病例。本地病例报告于5－12月,具有季节性和地方性特征,以8－11月高发（占98.26%）,发生在35°36'N以南省份,主要分布于广东（74.01%）和云南省（13.74%）。2014和2019年发生了2次登革热大暴发,本地病例数分别为46 033和15 376例（共占75.21%）。2005－2020年本地病例的男女性别比为0.99∶1；25～<55岁年龄组的病例占54.93%；本地病例数居前3位的职业是家务及待业（21.40%）、商业服务（12.46%）和离退人员（11.71%）。本地病例的年龄中位数为40岁[四分位距（IQR）：27～54]。2005年以来本地病例年龄中位数总体趋势差异无统计学意义（Z=1.510,P=0.131）。2005－2020年中国大陆除西藏自治区（西藏）以外的30个省（自治区、直辖市）共报告12 701例输入性病例。输入性病例全年均有报告,具有季节性和地方性特征,以6－11月高发（占81.81%）,主要分布于云南、广东、福建和浙江省。输入性病例主要来源于缅甸和柬埔寨等东南亚国家。2019年输入性病例数达峰值,为5 813例（占输入性病例总数的45.77%）。2005－2020年输入性病例数男女性别比为2.05∶1；25～<55岁年龄组的病例占73.29%；输入性病例数居前3位的职业是农民（24.13%）、商业服务（19.34%）和家务及待业（13.91%）。输入性病例的年龄中位数为33岁（IQR：26～44）。2005年以来输入性病例年龄中位数总体趋势差异无统计学意义（Z=0.413,P=0.679）。相较于2019年报告的15 376例本地病例和5 813例输入性病例,2020年登革热病例数有大幅度下降,报告616例本地病例和158例输入性病例。结论 我国登革热仍是由输入性病例引起的本地暴发,具有显著的地方性和季节性特征。本地病例主要分布于广东和云南省,输入性病例主要来源于缅甸、柬埔寨等东南亚国家,2005－2020年登革热病例年龄中位数无明显改变。

关键词: 登革热, 流行特征, 时间分布, 空间分布, 人群分布