背景:登革热(DF)已成为中国重要的公共卫生问题。时空模式和影响其传播的潜在因素,然而,仍然难以捉摸。本研究旨在确定驱动这些变化的因素,并评估中国DF流行的城市风险。
方法:我们分析了频率,强度,2003年至2022年中国DF病例分布,并评估了11个自然和社会经济因素作为潜在驱动因素。使用随机森林(RF)模型,我们评估了这些因素对当地DF流行的贡献,并预测了相应的城市风险.
结果:2003年至2022年,本地和输入性DF流行病例数(r=0.41,P<0.01)和受影响城市(r=0.79,P<0.01)之间存在显着相关性。随着输入性疫情发生频率和强度的增加,当地的流行病变得更加严重。它们的发生率从每年5个月增加到8个月,案件数量每月从14到6641。城市级DF流行病的空间分布与Huhuanyong线(Hu线)和秦山淮河线(Q-H线)定义的地理分区一致,并且与蚊媒活动(83.59%)或DF传播(95.74%)的城市级时间窗口非常匹配。当考虑时间窗时,RF模型实现了高性能(AUC=0.92)。重要的是,他们将输入病例确定为主要影响因素,在湖线东部地区(E-H地区)的城市层面上,对当地DF流行的贡献显着(24.82%)。此外,发现进口病例对当地流行病有线性促进作用,而五个气候因素和六个社会经济因素表现出非线性效应(促进或抑制),具有不同的拐点值。此外,该模型在预测中国地方流行病的城市级风险方面表现出出色的准确性(命中率=95.56%)。
结论:由于输入性DF流行的频率和强度不可避免地较高,中国正在经历零星的局部DF流行的增加。这项研究为卫生当局加强对这种疾病的干预能力提供了有价值的见解。
BACKGROUND: Dengue fever (DF) has emerged as a significant public health concern in China. The spatiotemporal patterns and underlying influencing its spread, however, remain elusive. This study aims to identify the factors driving these variations and to assess the city-level risk of DF epidemics in China.
METHODS: We analyzed the frequency, intensity, and distribution of DF cases in China from 2003 to 2022 and evaluated 11 natural and socioeconomic factors as potential drivers. Using the random forest (RF) model, we assessed the contributions of these factors to local DF epidemics and predicted the corresponding city-level risk.
RESULTS: Between 2003 and 2022, there was a notable correlation between local and imported DF epidemics in case numbers (r = 0.41, P < 0.01) and affected cities (r = 0.79, P < 0.01). With the increase in the frequency and intensity of imported epidemics, local epidemics have become more severe. Their occurrence has increased from five to eight months per year, with case numbers spanning from 14 to 6641 per month. The spatial distribution of city-level DF epidemics aligns with the geographical divisions defined by the Huhuanyong Line (Hu Line) and Qin Mountain-Huai River Line (Q-H Line) and matched well with the city-level time windows for either mosquito vector activity (83.59%) or DF transmission (95.74%). The RF models achieved a high performance (AUC = 0.92) when considering the time windows. Importantly, they identified imported cases as the primary influencing factor, contributing significantly (24.82%) to local DF epidemics at the city level in the eastern region of the Hu Line (E-H region). Moreover, imported cases were found to have a linear promoting impact on local epidemics, while five climatic and six socioeconomic factors exhibited nonlinear effects (promoting or inhibiting) with varying inflection values. Additionally, this model demonstrated outstanding accuracy (hitting ratio = 95.56%) in predicting the city-level risks of local epidemics in China.
CONCLUSIONS: China is experiencing an increasing occurrence of sporadic local DF epidemics driven by an unavoidably higher frequency and intensity of imported DF epidemics. This research offers valuable insights for health authorities to strengthen their intervention capabilities against this disease.