Research School of Population Health, The Australian National University, Canberra, ACT, Australia.
Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region, People's Republic of China.
Parasit Vectors. 2018 Feb 22;11(1):108. doi: 10.1186/s13071-018-2693-z.
Human cystic (CE) and alveolar (AE) echinococcoses are zoonotic parasitic diseases that can be influenced by environmental variability and change through effects on the parasites, animal intermediate and definitive hosts, and human populations. We aimed to assess and quantify the spatiotemporal patterns of human echinococcoses in Ningxia Hui Autonomous Region (NHAR), China between January 1994 and December 2013, and examine associations between these infections and indicators of environmental variability and change, including large-scale landscape regeneration undertaken by the Chinese authorities.
Data on the number of human echinococcosis cases were obtained from a hospital-based retrospective survey conducted in NHAR for the period 1 January 1994 through 31 December 2013. High-resolution imagery from Landsat 4/5-TM and 8-OLI was used to create single date land cover maps. Meteorological data were also collected for the period January 1980 to December 2013 to derive time series of bioclimatic variables. A Bayesian spatio-temporal conditional autoregressive model was used to quantify the relationship between annual cases of CE and AE and environmental variables.
Annual CE incidence demonstrated a negative temporal trend and was positively associated with winter mean temperature at a 10-year lag. There was also a significant, nonlinear effect of annual mean temperature at 13-year lag. The findings also revealed a negative association between AE incidence with temporal moving averages of bareland/artificial surface coverage and annual mean temperature calculated for the period 11-15 years before diagnosis and winter mean temperature for the period 0-4 years. Unlike CE risk, the selected environmental covariates accounted for some of the spatial variation in the risk of AE.
The present study contributes towards efforts to understand the role of environmental factors in determining the spatial heterogeneity of human echinococcoses. The identification of areas with high incidence of CE and AE may assist in the development and refinement of interventions for these diseases, and enhanced environmental change risk assessment.
人类囊性（CE）和肺泡（AE）包虫病是一种人畜共患寄生虫病，其流行状况可能受到环境变异性和变化的影响，这些变化会影响寄生虫、动物中间宿主和终末宿主以及人类群体。本研究旨在评估和量化 1994 年 1 月至 2013 年 12 月期间中国宁夏回族自治区（NHAR）的人类包虫病的时空分布模式，并研究这些感染与环境变异性和变化指标之间的关系，包括中国政府开展的大规模景观再生。
从 NHAR 医院回顾性调查中获取 1994 年 1 月 1 日至 2013 年 12 月 31 日期间的人类包虫病病例数数据。使用 Landsat 4/5-TM 和 8-OLI 的高分辨率图像创建单日期土地覆盖图。还收集了 1980 年 1 月至 2013 年 12 月的气象数据，以得出生物气候变量的时间序列。采用贝叶斯时空条件自回归模型来量化每年的 CE 和 AE 病例与环境变量之间的关系。
每年的 CE 发病率呈负时间趋势，与 10 年滞后的冬季平均温度呈正相关。在 13 年滞后的年均温度也存在显著的非线性效应。研究结果还表明，AE 发病率与诊断前 11-15 年的裸地/人工表面覆盖的时间移动平均值以及诊断前 0-4 年的冬季平均温度呈负相关。与 CE 风险不同，所选环境协变量解释了 AE 风险的部分空间变异性。
本研究有助于了解环境因素在确定人类包虫病空间异质性方面的作用。确定 CE 和 AE 发病率较高的地区可能有助于制定和完善这些疾病的干预措施，并增强对环境变化风险的评估。
