Spatiotemporal distribution of dengue fever in Hangzhou, Zhejiang, 2017–2019

  Objective  To understand the epidemiological characteristics and spatiotemporal distribution of imported and local dengue fever cases in Hangzhou, Zhejiang province, from 2017 to 2019.

  Methods   The incidence data of dengue fever in Hangzhou from 2017 to 2019 were collected from Infectious Disease Reporting Information Management System. According to the epidemiological survey data, the cases were divided into imported cases and local cases. Software ArcGIS 10.2 was used for spatial autocorrelation analysis and visual presentation. Software Satscan 9.4 was used for spatiotemporal scan analysis.

  Results   A total of 1 424 cases of dengue fever were reported in Hangzhou from 2017 to 2019, including 223 imported cases and 1 201 local cases. The incidence in 2017 and 2019 showed significant spatial clustering, with a total of 36 high-high clusters of local cases and 37 high-high clusters of imported cases. Spatiotemporal scanning analysis showed that a total of 3 clusters of local cases were detected, and the clustering time was between August and October in 2017. The class Ⅰ cluster area was in Zhanongkou of Jianggan district, involving 31 sub-districts in the urban area, and 3 clusters of imported cases were detected, and the clustering time was between May and November in 2019. The class I cluster area was in Tangqi of Yuhang District, involving 29 sub-district.

  Conclusion   Obvious spatiotemporal clustering of dengue fever cases was found in Hangzhou. There were some differences in spatiotemporal clustering and population distribution between local cases and imported cases. Different response measures should be taken in different areas for more precise prevention and control of dengue fever.