Knowledge of helminth life cycles is essential to understanding their host specificity, geographic distribution, and transmission. Many helminth life cycle descriptions are based on field collections in a limited part of the parasite's range. However, it is important to determine whether helminth life cycles and host specificity remain consistent across their geographic range so that we may better understand their life history and transmission ecology. Here, we investigated whether the life cycle of a widespread trematode, Quinqueserialis quinqueserialis (Notocotylidae) varies across its geographic range. Four species of planorbid snails; Gyraulus circumstriatus, Gyraulus crista, Planorbula sp., and Promenetus exacuous, were collected at 5 locations in Canada (3 in Manitoba, 2 in Northwest Territories). Snails and parasite larvae were morphologically and genetically identified to species. The total prevalence of Q. quinqueserialis infections in snail hosts among the 5 locations was 2.3% (n = 1,017). Three species of snails were infected with Q. quinqueserialis rediae: G. circumstriatus, G. crista, and P. exacuous. Two of the 3 species of snails were infected in central (Manitoba) and northern locations (Northwest Territories) within Canada, which indicates limited life cycle variation across a large geographic range. This is the first report of snails naturally infected with Q. quinqueserialis in Canada. These novel host records demonstrate that this trematode species is not as host-specific for first intermediate host species as previously described.

中文翻译：

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更广泛的地理采样增加了吸虫寄生虫（线虫科：Quinqueserialis quinqueserialis）的中等宿主特异性的程度。

了解蠕虫的生命周期对于了解它们的宿主特异性，地理分布和传播至关重要。许多蠕虫的生命周期描述都是基于寄生虫范围有限的田间采集的。但是，确定蠕虫的生命周期和宿主特异性在其地理范围内是否保持一致很重要，这样我们才能更好地了解它们的生活史和传播生态学。在这里，我们调查了广泛的吸虫（Quinqueserialis quinqueserialis）的生命周期是否在其地理范围内变化。四种平底蜗牛；在加拿大的5个地点（曼尼托巴省3个，西北地区2个）收集了回旋回旋回，回旋回，Planorbula sp。和Promenetus。蜗牛和寄生虫的幼虫在形态上和遗传上都被确定为物种。在这5个地点中，蜗牛宿主中的Q. quinqueserialis感染总发生率为2.3％（n = 1,017）。三种蜗牛都感染了昆士兰Q. quinqueserialis rediae：circumstriatus，Cr。crista和P. exacuous。3种蜗牛中的2种在加拿大的中部（曼尼托巴）和北部的位置（西北地区）被感染，这表明在较大的地理范围内生命周期变化有限。这是加拿大自然感染Q.qu​​inqueserialis的蜗牛的首次报道。这些新颖的宿主记录表明，该吸虫物种并不像先前描述的那样对于第一中间宿主物种具有宿主特异性。在5个地点中，蜗牛寄主中的quinqueserialis感染率为2.3％（n = 1,017）。三种蜗牛都感染了昆士兰Q. quinqueserialis rediae：circumstriatus，Cr。crista和P. exacuous。3种蜗牛中的2种在加拿大的中部（曼尼托巴）和北部的位置（西北地区）被感染，这表明在较大的地理范围内生命周期变化有限。这是加拿大自然感染Q.qu​​inqueserialis的蜗牛的首次报道。这些新颖的宿主记录表明，该吸虫物种并不像先前描述的那样对第一中间宿主物种具有宿主特异性。在5个地点中，蜗牛寄主中的quinqueserialis感染率为2.3％（n = 1,017）。三种蜗牛都感染了昆士兰Q. quinqueserialis rediae：circumstriatus，Cr。crista和P. exacuous。3种蜗牛中的2种在加拿大的中部（曼尼托巴）和北部的位置（西北地区）被感染，这表明在较大的地理范围内生命周期变化有限。这是加拿大自然感染Q.qu​​inqueserialis的蜗牛的首次报道。这些新颖的宿主记录表明，该吸虫物种并不像先前描述的那样对于第一中间宿主物种具有宿主特异性。3种蜗牛中的2种在加拿大的中部（曼尼托巴）和北部的位置（西北地区）被感染，这表明在较大的地理范围内生命周期变化有限。这是加拿大自然感染Q.qu​​inqueserialis的蜗牛的首次报道。这些新颖的宿主记录表明，该吸虫物种并不像先前描述的那样对于第一中间宿主物种具有宿主特异性。3种蜗牛中的2种在加拿大的中部（曼尼托巴）和北部的位置（西北地区）被感染，这表明在较大的地理范围内生命周期变化有限。这是加拿大自然感染Q.qu​​inqueserialis的蜗牛的首次报道。这些新颖的宿主记录表明，该吸虫物种并不像先前描述的那样对于第一中间宿主物种具有宿主特异性。