Spatiotemporal epidemiology and risk factors of scrub typhus in Hainan Province, China, 2011-2020

Lisha Liu; Yang Xiao; Xianyu Wei; Xuan Li; Chunyuan Duan; Xinjing Jia; Ruizhong Jia; Jinpeng Guo; Yong Chen; Xiushan Zhang; Wenyi Zhang; Yong Wang

doi:10.1016/j.onehlt.2023.100645

Spatiotemporal epidemiology and risk factors of scrub typhus in Hainan Province, China, 2011-2020

One Health. 2023 Oct 12:17:100645. doi: 10.1016/j.onehlt.2023.100645. eCollection 2023 Dec.

Authors

Lisha Liu^{1

2}, Yang Xiao³, Xianyu Wei^{1

2}, Xuan Li^{1

2}, Chunyuan Duan^{2

4}, Xinjing Jia^{2

4}, Ruizhong Jia², Jinpeng Guo^{2

4}, Yong Chen^{2

4}, Xiushan Zhang², Wenyi Zhang^{1

2

4}, Yong Wang^{1

2

4}

Affiliations

¹ Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China.
² Chinese PLA Center for Disease Control and Prevention, Beijing, China.
³ Chongqing University Cancer Hospital, School of Medicine, Chongqing University, Chongqing, China.
⁴ Department of Epidemiology and Biostatistics, School of Public Health, China Medical University, Shenyang, China.

Abstract

Background: The re-emergence of scrub typhus in the southern provinces of China in recent decades has been validated, thereby attracting the attention of public health authorities. There has been a spatial and temporal expansion of scrub typhus in Hainan Province, but the epidemiological characteristics, environmental drivers, and potential high-risk areas for scrub typhus have not yet been investigated.

Objective: The aims of this study were to characterize the spatiotemporal epidemiology of scrub typhus, identify dominant environmental risk factors, and map potential risk areas in Hainan Province from 2011 to 2020.

Methods: The spatiotemporal dynamics of scrub typhus in Hainan Province between 2011 and 2020 were analyzed using spatial analyses and seasonal-trend decomposition using regression (STR). The maximum entropy (MaxEnt) model was applied to determine the key environmental predictors and environmentally suitable areas for scrub typhus, and the demographic diversity of the predicted suitable zones was evaluated.

Results: During 2011-2020, 3260 scrub typhus cases were recorded in Hainan Province. The number of scrub typhus cases increased continuously each year, particularly among farmers (67.61%) and individuals aged 50-59 years (23.25%) who were identified as high-risk groups. A dual epidemic peak was detected, emerging annually from April to June and from July to October. The MaxEnt-based risk map illustrated that highly suitable areas, accounting for 25.36% of the total area, were mainly distributed in the northeastern part of Hainan Province, where 75.43% of the total population lived. Jackknife tests revealed that ground surface temperature, elevation, cumulative precipitation, evaporation, land cover, population density, and ratio of dependents were the most significant environmental factors.

Conclusion: In this study, we gained insights into the spatiotemporal epidemiological dynamics, pivotal environmental drivers, and potential risk map of scrub typhus in Hainan Province. These results have important implications for researchers and public health officials in guiding future prevention and control strategies for scrub typhus.

Keywords: Environmental factors; Maximum entropy modeling; Scrub typhus; Spatiotemporal epidemiology.