[Trend of epidemics and variation of pathogens of hand, foot and mouth disease in China: a dynamic series analysis, 2008-2017].

Objective: To understand the trend of epidemics and variation of pathogens on hand, foot and mouth diseases (HFMD) in China for setting up appropriate intervention measures. Methods: Data related to reported cases and outbreaks of HFMD from the National Notifiable Disease Surveillance Reporting System of China, 2008 to 2017, was collected and analyzed. Based on the geographical location and types of climate, the total 31 provinces, autonomous regions and municipalities in the mainland of China, were divided into seven regions: north-west, north, mid-north, east, mid-south, south, and south-west regions, with epidemic trends and variation of pathogens analyzed. The average speed of growth on the dynamic series from 2008 to 2017 was calculated, using the Geometric Average method. Results: The overall reported incidence rate of HFMD during 2008-2017 was 134.59 per 100 000 population with an average increase of 15.92%. The proportion of severe cases was 0.84%, with 9.56% increase. The reported mortality rate of HFMD was 0.03/100 000, with an average decrease of 3.49%. The case fatality rate was 0.02% and with a decrease of 16.86%. A total of 6 000 outbreaks were reported during the decade. Except for 1.09% decrease on the incidence rate in the north region, all the other regions showed an increase on the morbidity rates, with the highest as25.20% in the south region. Mortality rates showed 27.53% and 0.60% increases in both the south-west and mid-north regions, respectively. Mortality rates in the other regions all showed a decreasing trend. In terms of case fatality rate, it increased 4.15% in the south-west region while all decreased in the other regions. Two higher age-special morbidity rates appeared in the 1 year olds as 3 184.19/100 000 and in the 2 year olds as 2 547.47/100 000, with the most increase seen in both 0 year (26.08%) and 1 year age groups (23.35%). High age-specific mortality rates were noticed in both the 1-year group as 0.86/100 000 and the 2-year group as 0.54/100 000, however with reductions as 1.21% and 10.70% respectively. As for the case fatalities, the 0 year olds and 1 year olds accounted for 0.039% and 0.027% but both of them had decreased by 19.12% and 19.91%, respectively. Case fatality rates decreased by 16.93% and 16.75%, in males and females. Proportions of EV71 and Cox A16 decreased by 4.28% and 3.07%, but the proportion of other entero-viruses increased by 16.07%. EV71 was responsible for the high frequency of epidemics in both mid-north and the mid-south regions. However, in other five regions, other strains of EV's were responsible for the epidemics. Conclusions: The characteristics of HFMD in China showed that the morbidity of HFMD and proportion of severe cases were both in increasing trends but both the mortality and case fatality of HFMD were decreasing. Children younger than 3 years old showed both high infection and death rates for HFMD. Epidemics caused by other enteroviruses of non-EV71 and non-Cox A16 were seen more. Variance and pathogens related to the epidemic cycles appeared different in the seven regions.目的： 了解中国手足口病疫情变化趋势，为制定防控策略提供依据。 方法： 在中国疾病预防控制信息报告系统收集2008－2017年中国大陆手足口病报告病例个案和暴发数据，按地理位置将31个省份划分为西北部、北部、中北部、东部、中南部、南部和西南部7个片区，采用描述流行病学方法进行分析，用动态数列几何平均法计算平均增长速度。 结果： 2008－2017年全国手足口病报告发病率为134.59/10万，平均增长15.92%，报告重症比例为0.84%，平均增长9.56%，报告死亡率为0.03/10万，平均下降3.49%，报告病死率为0.02%，平均下降16.86%。累计报告暴发疫情6 000起。除北部发病率下降1.09%，其余片区发病率均上升，以南部增幅最大（25.20%）。西南部和中北部死亡率分别上升27.53%和0.60%，其余片区均下降。西南部病死率上升4.15%，其余片区均下降。年龄别发病率前2位为1~岁组（3 184.19/10万）和2~岁组（2 547.47/10万），上升幅度前2位为0~岁组（26.08%）和1~岁组（23.35%）。死亡率居前2位的是1~岁组（0.86/10万）和2~岁组（0.54/10万），分别下降1.21%和10.70%。病死率居前2位为0~岁组（0.039%）和1~岁组（0.027%），分别下降19.12%和19.91%。男、女性病死率分别下降16.93%和16.75%。肠道病毒71型（EV71）和柯萨奇病毒A组16型（Cox A16）构成比分别下降4.28%和3.07%，其他肠道病毒构成比上升16.07%。中北部和中南部以EV71占优势，其余片区以其他肠道病毒占优势。 结论： 中国大陆地区手足口病呈现报告发病率、重症比例上升，死亡率、病死率下降的特点。3岁以下儿童仍是手足口病高危人群，非EV71和非Cox A16流行强度增加，流行特征和病原变化趋势存在明显地区间差异。.