Fakhar Mahdi, Karamian Mehdi, Ghatee Mohammad Amin, Taylor Walter Robert, Pazoki Ghohe Hossein, Rasooli Sayed Abobakar
Molecular and Cell Biology Research Center, Department of Parasitology and Mycology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
Infectious Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran.
Acta Trop. 2017 Dec;176:22-28. doi: 10.1016/j.actatropica.2017.07.028. Epub 2017 Jul 25.
Anthroponotic cutaneous leishmaniasis (ACL), caused by Leishmania tropica, is the main cause of cutaneous leishmaniasis (CL) in the Herat province, Western Afghanistan. We investigated the role of environmental factors on ACL distribution in Herat. Epidemiological data from 2457 patients were retrieved from the local WHO sub-office. Shapefile layers of districts, cities, villages, land cover, soil type and digital elevation model (DEM) of the Herat province were used to assess, by logistic regression modelling, the effects of land cover, soil types, elevation, and proximity to the Harirud river on the distribution of ACL. The key determinants of distribution were: (i) close proximity to the Harirud river, (ii) elevation between 700 and 1200m, (iii) intensive and intermittent irrigated cultivated land, and (iv) Haplocalcids with Torriorthents and Torrifluvents soil types. No ACL cases were found below 700m, and a few cases were present at >1200m in irrigated areas around the Harirud river. These findings suggest that moist soil and the humidity from irrigated areas found between 700 and 1200m provide suitable breeding sites of Phlebotomus sergenti, the main sandfly vector of L. tropica in Afghanistan. The effect of elevation also explains the predominance of ACL over ZCL in this region. The present study showed that distribution of ACL is strongly associated with environmental factors in West Afghanistan where the political and socio-economic conditions may also affect the epidemiology of CL.
由热带利什曼原虫引起的人源性皮肤利什曼病（ACL）是阿富汗西部赫拉特省皮肤利什曼病（CL）的主要病因。我们调查了环境因素对赫拉特省ACL分布的作用。从当地世界卫生组织分办事处获取了2457名患者的流行病学数据。利用赫拉特省的地区、城市、村庄、土地覆盖、土壤类型和数字高程模型（DEM）的Shapefile图层，通过逻辑回归模型评估土地覆盖、土壤类型、海拔以及与哈里鲁德河的距离对ACL分布的影响。分布的关键决定因素为：（i）靠近哈里鲁德河；（ii）海拔在700至1200米之间；（iii）集约和间歇性灌溉耕地；（iv）含有雏形钙积土和雏形新成土土壤类型的弱发育钙层土。在海拔700米以下未发现ACL病例，在哈里鲁德河周边灌溉区域海拔>1200米处有少数病例。这些发现表明，700至1200米之间湿润的土壤和灌溉区域的湿度为阿富汗热带利什曼原虫的主要沙蝇传播媒介——塞尔吉白蛉提供了适宜的繁殖场所。海拔的影响也解释了该地区ACL相对于动物源性皮肤利什曼病（ZCL）的优势。本研究表明，在阿富汗西部，ACL的分布与环境因素密切相关，而当地的政治和社会经济状况也可能影响CL的流行病学。
