Epidemiological features and spatial\u2013temporal distribution of visceral leishmaniasis in mainland China: a population-based surveillance study from 2004 to 2019

Zhou Guan,Shigui Yang,Zhengbin Zhou,Yiyi Zhou,Jie Wu,Can Chen,Hongwei Zhang,Lanjuan Li,Yuqing Zhou,Chenyang Huang

doi:10.1186/s13071-021-05002-y

Abstract

BackgroundAlthough visceral leishmaniasis (VL) was largely brought under control in most regions of China during the previous century, VL cases have rebounded in western and central China in recent decades. The aim of this study was to investigate the epidemiological features and spatial–temporal distribution of VL in mainland China from 2004 to 2019.MethodsIncidence and mortality data for VL during the period 2004–2019 were collected from the Public Health Sciences Data Center of China and annual national epidemic reports of VL, whose data source was the National Diseases Reporting Information System. Joinpoint regression analysis was performed to explore the trends of VL. Spatial autocorrelation and spatial–temporal clustering analysis were conducted to identify the distribution and risk areas of VL transmission.ResultsA total of 4877 VL cases were reported in mainland China during 2004–2019, with mean annual incidence of 0.0228/100,000. VL incidence showed a decreasing trend in general during our study period (annual percentage change [APC] = −4.2564, 95% confidence interval [CI]: −8.0856 to −0.2677). Among mainly endemic provinces, VL was initially heavily epidemic in Gansu, Sichuan, and especially Xinjiang, but subsequently decreased considerably. In contrast, Shaanxi and Shanxi witnessed significantly increasing trends, especially in 2017–2019. The first-level spatial–temporal aggregation area covered two endemic provinces in northwestern China, including Gansu and Xinjiang, with the gathering time from 2004 to 2011 (relative risk [RR] = 13.91, log-likelihood ratio [LLR] = 3308.87, P < 0.001). The secondary aggregation area was detected in Shanxi province of central China, with the gathering time of 2019 (RR = 1.61, LLR = 4.88, P = 0.041). The epidemic peak of October to November disappeared in 2018–2019, leaving only one peak in March to May.ConclusionsOur findings suggest that VL is still an important endemic infectious disease in China. Epidemic trends in different provinces changed significantly and spatial–temporal aggregation areas shifted from northwestern to central China during our study period. Mitigation strategies, including large-scale screening, insecticide spraying, and health education encouraging behavioral change, in combination with other integrated approaches, are needed to decrease transmission risk in areas at risk, especially in Shanxi, Shaanxi, and Gansu provinces.Graphical abstract

Highlights

Visceral leishmaniasis (VL) was largely brought under control in most regions of China during the previous century, visceral leishmaniasis (VL) cases have rebounded in western and central China in recent decades
Our findings suggest that VL is still an important endemic infectious disease in China
The trend in VL incidence from 2004 to 2019 A total of 4877 VL cases and 13 deaths were reported in mainland China during the period 2004–2019

Summary

Introduction

Visceral leishmaniasis (VL) was largely brought under control in most regions of China during the previous century, VL cases have rebounded in western and central China in recent decades. Since the 2000s, the endemic regions have expanded to more than 80 counties of eight provinces, including the Xinjiang Uygur Autonomous Region, Gansu, Sichuan, Shaanxi, Shanxi, Henan, Hebei, and the Inner Mongolia Autonomous Region [18]. During this historical period, two epidemiological species of VL, namely anthroponotic and zoonotic types, were identified in mainland China [19]

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