Spatio-temporal clustering of Mountain-type Zoonotic Visceral Leishmaniasis in China between 2015 and 2019

Abstract

With several decades of concerted control efforts, visceral leishmaniasis(VL) eradication had almost been achieved in China. However, VL cases continue to be detected in parts of western China recent years. Using data of reported cases, this study aimed to investigate the epidemiology and spatio⁃temporal distribution, of mountain-type zoonotic visceral leishmaniasis (MT-ZVL) in China between the years 2015 and 2019. Epidemiological data pertaining to patients with visceral leishmaniasis (VL) were collected in Gansu, Shaanxi, Sichuan, Shanxi, Henan and Hebei provinces between the years 2015 and 2019. Joinpoint regression analysis was performed to determine changes in the epidemic trend of MT-ZVL within the time period during which data was collected. Spatial autocorrelation of infection was examined using the Global Moran’s I statistic wand hotspot analysis was carried out using the Getis-Ord Gi* statistic. Spatio-temporal clustering analysis was conducted using the retrospective space-time permutation flexible spatial scanning statistics. A total of 529 cases of MT-ZVL were detected in the six provinces from which data were collected during the study time period, predominantly in Gansu (55.0%), Shanxi (21.7%), Shaanxi (12.5%) and Sichuan (8.9%) provinces. A decline in VL incidence in China was observed during the study period, whereas an increase in MT-ZVL incidence was observed in the six provinces from which data was obtained (t = 4.87, P < 0.05), with highest incidence in Shanxi province (t = 16.91, P < 0.05). Significant differences in the Moran’s I statistic were observed during study time period (P < 0.05), indicating spatial autocorrelation in the spatial distribution of MT-ZVL. Hotspot and spatial autocorrelation analysis revealed clustering of infection cases in the Shaanxi-Shanxi border areas and in east of Shanxi province, where transmission increased rapidly over the study duration, as well as in well know high transmission areas in the south of Gansu province and the north of the Sichuan province. It indicates resurgence of MT-ZVL transmission over the latter three years of the study. Spatial clustering of infection was observed in localized areas, as well as sporadic outbreaks of infection.

Total RNA sequencing of Phlebotomus chinensis sandflies in China revealed viral, bacterial, and eukaryotic microbes potentially pathogenic to humans

“…The disease caused by Leishmania has been frequently reported in Shanxi province, which recorded 21.7% of the total mountain-type zoonotic visceral leishmaniasis cases between 2015 and–2019 in China, and, therefore, it is viewed as one of the hotspot regions for visceral leishmaniasis [ 42 ]. Furthermore, previous studies based on real-time quantitative PCR suggested that the average prevalence of Leishmania was 1.98% in female Ph.…”

Epidemiological features and spatial-temporal clustering of visceral leishmaniasis in mainland China from 2019 to 2021

“…As a momentous parasitic disease, VL has been brought under control in China ( Wang et al, 2000 ). However, with the development of society and the improvement in the ecological environment, the incidence of MT-ZVL rocketed rapidly and generated new hotspots in central China recently ( Zhou et al, 2020a , b ; Guan et al, 2021 ; Hao et al, 2021 ). Therefore, the objective of this study was to retrospectively analyze the epidemiology and spatiotemporal distribution characteristics of VL in China from 2019 to 2021, aiming to provide insights into the prevention and control of VL.…”

“…The substantial increase in the incidence of MT-ZVL in China may be related to the emergence of VL in the historically endemic areas and the formation of some new hotspot areas of MT-ZVL ( Zhou et al, 2020c ; Guan et al, 2021 ; Hao et al, 2021 ). Between 2019 and 2021, a total of 27 new reemerged historically endemic counties were identified that were mainly located in Shanxi, Shaanxi, Henan, and Hebei Provinces and Beijing municipality, where 54 VL cases were notified.…”

“… Zheng et al (2020) executed a spatio-temporal analysis of VL in northwest China from 2004 to 2018, showing that VL is still seriously prevalent in Kashi Prefecture, Xinjiang Uygur Autonomous Region. Hao et al (2021) conducted a spatio-temporal clustering analysis of MT-ZVL in central China. Guan et al (2021) detected the shifting of high-incidence areas of VL through spatial-temporal distribution analysis in mainland China.…”

Establishment of an indicator framework for transmission risk of the Mountain-Type Zoonotic Visceral Leishmaniasis based on the Delphi-entropy weight method

“…Additionally, the topography was also considered an important indicator of MT-ZVL transmission risk. Historically, MT-ZVL was closely related to topography and was mainly distributed in hilly settings of Gansu, Sichuan, Shanxi, Shaanxi, western Henan, and northern Hebei, Qinghai, Ningxia, Liaoning, and the suburbs of Beijing [34]. These areas were mainly extension areas of the Loess Plateau, which provides a suitable habitat for wild reservoirs hosts and sand ies to maintain the MT-ZVL transmission cycle [14,35].…”