Department of Medical Parasitology and Mycology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
Department of Medical Parasitology and Mycology, Urmia University of Medical Sciences, Urmia, Iran.
Parasit Vectors. 2024 May 31;17(1):244. doi: 10.1186/s13071-024-06298-2.
Snails of the Lymnaeidae family are the intermediate hosts of Fasciola species, the causative agents of fascioliasis. The purpose of this study was to determine the prevalence of Fasciola species in lymnaeid snails and to investigate the association of geoclimatic factors and Fasciola species distribution in northwestern provinces of Iran using geographical information system (GIS) data.
A total of 2000 lymnaeid snails were collected from 33 permanent and seasonal habitats in northwestern Iran during the period from June to November 2021. After identification by standard morphological keys, they were subjected to shedding and crushing methods. Different stages of Fasciola obtained from these snails were subjected to the ITS1 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for species identification. The associations of weather temperature, rainfall, humidity, evaporation, air pressure, wind speed, elevation, and land cover with the distribution of Fasciola species were investigated. Geographical and statistical analysis was performed using ArcMap and SPSS software, respectively, to determine factors related to Fasciola species distribution.
Of the 2000 snails collected, 19 were infected with Fasciola hepatica (0.09%), six with F. gigantica (0.03%), and 13 with other trematodes. Among geoclimatic and environmental factors, mean humidity, maximum humidity, and wind speed were significantly higher in areas where F. hepatica was more common than F. gigantica. The altitude of F. hepatica-prevalent areas was generally lower than F. gigantica areas. No significant relationship was observed between other investigated geoclimatic factors and the distribution of infected snails.
The present study showed the relationship of humidity and wind speed with the distribution of snails infected with F. hepatica or F. gigantica in the northwestern regions of Iran. In contrast to F. gigantica, F. hepatica was more prevalent in low-altitude areas. Further research is recommended to elucidate the relationship between geoclimatic factors and the presence of intermediate hosts of the two Fasciola species.
豆螺科的蜗牛是片形吸虫属的中间宿主，片形吸虫属是片形吸虫病的病原体。本研究旨在确定伊朗西北部地区豆螺科蜗牛中片形吸虫属的流行情况，并利用地理信息系统 (GIS) 数据调查地理气候因素与片形吸虫属分布的关系。
2021 年 6 月至 11 月期间，从伊朗西北部的 33 个永久性和季节性栖息地共采集了 2000 只豆螺科蜗牛。经标准形态学鉴定后，采用蜕皮和压碎法。从这些蜗牛中获得的不同阶段的片形吸虫，采用 ITS1 聚合酶链反应-限制性片段长度多态性 (PCR-RFLP) 方法进行物种鉴定。调查了天气温度、降雨量、湿度、蒸发量、气压、风速、海拔和土地覆盖与片形吸虫属分布的关系。使用 ArcMap 和 SPSS 软件分别进行地理和统计分析，以确定与片形吸虫属分布相关的因素。
在采集的 2000 只蜗牛中，有 19 只感染了肝片形吸虫（0.09%），6 只感染了巨片形吸虫（0.03%），13 只感染了其他吸虫。在地理气候和环境因素中，肝片形吸虫感染率较高的地区平均湿度、最高湿度和风速明显高于巨片形吸虫感染率较高的地区。肝片形吸虫感染率较高地区的海拔普遍低于巨片形吸虫感染率较高地区。其他调查的地理气候因素与感染蜗牛的分布之间没有观察到显著关系。
本研究表明，湿度和风速与伊朗西北部地区感染 F. hepatica 或 F. gigantica 的蜗牛分布有关。与 F. gigantica 相比，F. hepatica 更常见于低海拔地区。建议进一步研究以阐明地理气候因素与两种片形吸虫中间宿主存在之间的关系。
