Epidemiological characteristics and spatiotemporal distribution of hemorrhagic fever with renal syndrome in Ningbo, Zhejiang, 2005−2021

  Objective  To investigate the epidemiological characteristics and spatiotemporal distribution of hemorrhagic fever with renal syndrome (HFRS) in Ningbo, Zhejiang province, from 2005 to 2021, and provide evidence for the formulation of precise prevention and control measures for HFRS.

  Methods  The incidence data of HFRS in Ningbo during 2005−2021 were collected from China National Notifiable Infectious Disease Reporting Information System (NNDS) for a descriptive analysis. Software ArcGIS 10.8 was used for spatial autocorrelation analysis and visual presentation.

  Results  A total of 1903 cases of HFRS were reported in Ningbo from 2005 to 2021, with an average annual incidence rate of 1.50/100 000. The distribution of cases showed a clear seasonal pattern, with peaks from April to June and from November to January. The cases were mainly people aged 30–60 (66.00%), and the cases were mainly farmers (53.91%), the male to female ratio of the cases was 3.04∶1. Yinzhou, Xiangshan, Fenghua and Ninghai were the areas with high incidence of HFRS in Ningbo, with reported cases accounting for 74.25% (1413/1903) of the total. The result of the global spatial autocorrelation analysis showed that the incidence of HFRS in all towns/streets in Ningbo had spatial clustering from 2015 to 2018 (all P<0.05). Local spatial autocorrelation analysis showed that the incidence of HFRS during 2015–2019 had hot spots (H-H), and the range of hot spots showed dynamic changes. Two clustering areas were detected by spatial-temporal clustering analysis. The class Ⅰ clustering area was in Qiangtou of Xiangshan, involving 41 sub-districts in southeast Ningbo, during June 1, 2017 - June 30, 2019. The class Ⅱ cluster area was in Yinjiang of Haishu, involving 3 sub-districts in the urban area, during June 1, 2015 - June 30, 2017.

  Conclusion  Obvious spatiotemporal clustering of HFRS cases was found in Ningbo from 2015 to 2019 and clustering areas changed dynamically from the south central part to the west in Ningbo. It is necessary to strengthen the prevention and control programs of HFRS in these areas.