Species Identification and Genetic Diversity of Freshwater Snails in the Qinghai Lake Basin of the Qinghai–Tibet Plateau: Implications for Fascioliasis Control

To investigate freshwater snail distribution, which are intermediate hosts of Fasciola hepatica (Linnaeus, 1758), in pastoral areas around Qinghai Lake and provide a scientific basis for fascioliasis control in Qinghai Province of Qinghai–Tibet Plateau, 234 snail samples were collected from Gangcha and Haiyan Counties. After preliminary screening by morphology, species confirmation and phylogenetic analysis were performed using cytochrome c oxidase I (cox1) sequencing. All 234 samples passed quality control, and five species were identified: Radix auricularia (28.6%, 67/234) (Linnaeus, 1758), Tibetoradix kruglovi (27.4%, 64/234) (Vinarski, 2022), Orientogalba ollula (28.2%, 66/234) (Gould, 1859), Orientogalba viridis (6.0%, 14/234) (Quoy, 1833), and Gyraulus chinensis (9.8%, 23/234) (Dunker, 1848). Notably, T. kruglovi (an endemic species specific to the Qinghai–Tibet Plateau) was dominant in high-altitude Gangcha (ca. 3,300 m), in striking contrast to the multispecies assemblage in Haiyan (ca. 3,000 m), suggesting possibly altitude-driven geographic isolation. Haplotype network analysis indicated recent demographic expansions in T. kruglovi, O. ollula, and G. chinensis. This study represents the first basin-wide investigation of freshwater snail biodiversity and genetic structure around Qinghai Lake, providing critical data to inform targeted fascioliasis control strategies.