Division of Infectious Disease, Gansu Provincial Center for Disease Control and Prevention, Lanzhou, China.
School of Public Health and Social Work, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.
Environ Res. 2020 Apr;183:109189. doi: 10.1016/j.envres.2020.109189. Epub 2020 Jan 30.
Seasonal influenza remains epidemic globally with a substantial health burden. Understanding the transmission patterns and epidemic features of influenza may facilitate the improvement of preventive and control measures. This study aims to assess the epidemic features of influenza among different climate zones and identify high-risk zones across Gansu province, China.
We collected weekly influenza cases at county-level between 1st January 2012 and 31st December 2016, as well as climate zones classification shapefile data from Köppen-Geiger climate map. We compared the epidemic features (Frequency index (α), Duration index (β) and Intensity index (γ)) of influenza among different climate zones. Spatial cluster analysis was used to examine the high-risk areas of transmission of influenza.
The distribution of cases existed significant differences among eight climate zones (F-test: 267.02, p < 0.05). The highest mean weekly incidence rate (per 100,000 population) was 0.59 in snow climate with dry winter and warm summer (Dwb). The primary (relative risk (RR): 3.61, p < 0.001) and secondary (RR: 2.45, p < 0.001) clusters were located in Dwb. The highest values of α, β and γ were 1.00, 261 and 154.38 in Dwb. The hot spots (high-high clusters) of the epidemic indices were detected in Dwb.
This study found the variability of epidemic features of influenza among eight climate zones. We highlight that Dwb was the high-risk zone where influenza clustered with the highest incidence rate and epidemic temporal indices. This provide further insight into potential improvement of preventive measures by climate zones to minimize the impact of epidemics.
季节性流感在全球范围内仍呈流行态势，给健康带来了巨大负担。了解流感的传播模式和流行特征，有助于改善预防和控制措施。本研究旨在评估甘肃省不同气候带流感的流行特征，并确定全省高风险区域。
我们收集了 2012 年 1 月 1 日至 2016 年 12 月 31 日县级每周流感病例数据，以及柯本-盖格尔气候图的气候带分类形状文件数据。我们比较了不同气候带流感的流行特征（频率指数（α）、持续时间指数（β）和强度指数（γ））。采用空间聚类分析方法，研究流感传播的高风险区域。
八个气候带的病例分布存在显著差异（F 检验：267.02，p<0.05）。雪带干冬雨暖夏（Dwb）的每周平均发病率（每 10 万人）最高，为 0.59。主要（相对风险（RR）：3.61，p<0.001）和次要（RR：2.45，p<0.001）聚集区位于 Dwb。α、β和γ的最高值分别为 1.00、261 和 154.38，均出现在 Dwb。在 Dwb 检测到流行指标的热点（高高聚集区）。
本研究发现，甘肃省八个气候带的流感流行特征存在差异。我们强调 Dwb 是流感聚集的高风险区域，其发病率和流行时间指数最高。这为进一步根据气候带改善预防措施，最大程度降低疫情影响提供了依据。
