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Abstract：
BACKGROUND: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.
摘要：
背景：Lymnaeidae家族的蜗牛是Fasciola物种的中间宿主，筋膜的病原体。这项研究的目的是确定lymnaeid蜗牛中Fasciola物种的患病率，并使用地理信息系统（GIS）数据调查伊朗西北部省份的地气候因素与Fasciola物种分布之间的关联。
方法：在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收集了总共2000只lymnaeid蜗牛。通过标准形态学键识别后，他们受到脱落和压碎的方法。对从这些蜗牛获得的Fasciola的不同阶段进行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。天气温度的关联，降雨,湿度,湿度蒸发,空气压力,风速,高程,并对Fasciola物种分布的土地覆盖进行了调查。使用ArcMap和SPSS软件进行地理和统计分析。分别,以确定相关因素的片尾属植物的种类分布。
结果：在收集的2000只蜗牛中，19例感染肝片吸虫(0.09%)，六个与F.gigantica（0.03%），和13与其他吸虫。在地气候和环境因素中，平均湿度,最大湿度,在肝菌比巨大弧菌更常见的地区，风速明显更高。肝菌流行地区的海拔高度普遍低于大肝菌地区。在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着关系。
结论：本研究显示了湿度和风速与伊朗西北地区感染肝弧菌或巨大弧菌的蜗牛分布的关系。与F.gigantica相比，F.Hepatca在低海拔地区更为普遍。建议进一步研究以阐明地球气候因素与两种Fasciola物种中间宿主的存在之间的关系。
方法：在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收集了总共2000只lymnaeid蜗牛。通过标准形态学键识别后，他们受到脱落和压碎的方法。对从这些蜗牛获得的Fasciola的不同阶段进行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。天气温度的关联，降雨,湿度,湿度蒸发,空气压力,风速,高程,并对Fasciola物种分布的土地覆盖进行了调查。使用ArcMap和SPSS软件进行地理和统计分析。分别,以确定相关因素的片尾属植物的种类分布。
结果：在收集的2000只蜗牛中，19例感染肝片吸虫(0.09%)，六个与F.gigantica（0.03%），和13与其他吸虫。在地气候和环境因素中，平均湿度,最大湿度,在肝菌比巨大弧菌更常见的地区，风速明显更高。肝菌流行地区的海拔高度普遍低于大肝菌地区。在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着关系。
结论：本研究显示了湿度和风速与伊朗西北地区感染肝弧菌或巨大弧菌的蜗牛分布的关系。与F.gigantica相比，F.Hepatca在低海拔地区更为普遍。建议进一步研究以阐明地球气候因素与两种Fasciola物种中间宿主的存在之间的关系。
