Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Zhejiang Key Lab of Vaccine, Infectious Disease Prevention and Control, Hangzhou, Zhejiang, China.
Front Public Health. 2024 Sep 26;12:1359318. doi: 10.3389/fpubh.2024.1359318. eCollection 2024.
China is one of the main epidemic areas of scrub typhus, and Zhejiang Province, which is located in the coastal area of southeastern China, is considered a key region of scrub typhus. However, there may be significant bias in the number of reported cases of scrub typhus, to the extent that its epidemiological patterns are not clearly understood. The purpose of this study was to estimate the possible incidence of scrub typhus and to identify the main driving components affecting the occurrence of scrub typhus at the county level.
Data on patients with scrub typhus diagnosed at medical institutions between January 2016 and December 2023 were collected from the China Disease Control and Prevention Information System (CDCPIS). The kriging interpolation method was used to estimate the possible incidence of scrub typhus. Additionally, a multivariate time series model was applied to identify the main driving components affecting the occurrence of scrub typhus in different regions.
From January 2016 to September 2023, 2,678 cases of scrub typhus were reported in Zhejiang Province, including 1 case of reported death, with an overall case fatality rate of 0.04%. The seasonal characteristics of scrub typhus in Zhejiang Province followed an annual single peak model, and the months of peak onset in different cities were different. The estimated area with case occurrence was relatively wider. There were 41 counties in Zhejiang Province with an annual reported case count of less than 1, while from the estimated annual incidence, the number of counties with less than 1 case decreased to 21. The average annual number of cases in most regions fluctuated between 0 and 15. The numbers of cases in the central urban area of Hangzhou city, Jiaxin city and Huzhou city did not exceed 5. The estimated random effect variance parameters , , and were 0.48, 1.03 and 3.48, respectively. The endemic component values of the top 10 counties were Shuichang, Cangnan, Chun'an, Xinchang, Pingyang, Xianju, Longquan, Dongyang, Yueqing and Qingyuan. The spatiotemporal component values of the top 10 counties were Pujiang, Anji, Pan'an, Dongyang, Jinyun, Ninghai, Yongjia, Xiaoshan, Yinwu and Shengzhou. The autoregressive component values of the top 10 counties were Lin'an, Cangnan, Chun'an, Yiwu, Pujiang, Longquan, Xinchang, Luqiao, Sanmen and Fuyang.
The estimated incidence was higher than the current reported number of cases, and the possible impact area of the epidemic was also wider than the areas with reported cases. The main driving factors of the scrub typhus epidemic in Zhejiang included endemic components such as natural factors, but there was significant heterogeneity in the composition of driving factors in different regions. Some regions were driven by spatiotemporal spread across regions, and the time autoregressive effect in individual regions could not be ignored. These results that monitoring of cases, vectors, and pathogens of scrub typhus should be strengthened. Furthermore, each region should take targeted prevention and control measures based on the main driving factors of the local epidemic to improve the accuracy of prevention and control.
中国是恙虫病的主要流行区之一，地处中国东南部沿海地区的浙江省被认为是恙虫病的重点区域。然而，恙虫病报告病例数量可能存在较大偏差，以至于其流行病学模式尚不清楚。本研究旨在估算恙虫病的可能发病率，并确定影响县级恙虫病发生的主要驱动因素。
从中国疾病预防控制信息系统（CDCPIS）中收集了 2016 年 1 月至 2023 年 12 月期间医疗机构诊断的恙虫病患者数据。采用克里金插值法估算恙虫病的可能发病率。此外，应用多变量时间序列模型来识别不同地区影响恙虫病发生的主要驱动因素。
2016 年 1 月至 2023 年 9 月，浙江省共报告 2678 例恙虫病病例，包括 1 例死亡病例，总病死率为 0.04%。浙江省恙虫病具有季节性特征，呈单峰型年度分布，不同城市的发病高峰月份不同。估计有病例发生的区域范围相对较广。浙江省有 41 个县的年报告病例数少于 1 例，而从估计的年发病率来看，病例数少于 1 例的县减少到 21 个。多数地区的年平均病例数在 0 至 15 例之间波动。杭州市、嘉兴市和湖州市中心城区的病例数均未超过 5 例。估计的随机效应方差参数 、 、 分别为 0.48、1.03 和 3.48。排名前 10 位的县的地方病成分值分别为遂昌、苍南、淳安、新昌、平阳、仙居、龙泉、东阳、乐清和青田。排名前 10 位的县的时空成分值分别为浦江、安吉、磐安、东阳、缙云、宁海、永嘉、萧山、鄞州区和嵊州。排名前 10 位的县的自回归成分值分别为临安、苍南、淳安、义乌、浦江、龙泉、新昌、路桥、三门和富阳。
估计的发病率高于当前报告的病例数，可能的流行区域也比报告病例的区域更广。浙江省恙虫病疫情的主要驱动因素包括自然因素等地方病成分，但不同地区的驱动因素构成存在显著异质性。部分地区的疫情受跨区域时空传播驱动，个别地区的时间自回归效应不容忽视。这些结果表明，应加强对恙虫病病例、病媒和病原体的监测。此外，各地区应根据当地疫情的主要驱动因素采取有针对性的防控措施，以提高防控的准确性。
