[Investigation of the population diversity of intermediate host snails and crabs of along Jiulong River, Zhangjiang River and Dongxi River basins in southern Fujian Province].

Objective: To investigate the population distribution of intermediate host snails and crabs of along the Jiulongjiang River, Zhangjiang River, and Dongxi River basins in Bopingling Mountain, southern Fujian Province, so as to provide baseline data for researches on parasitic disease prevention and control and enlargement of samples in the parasitic resource bank.

Methods: A total of 23 villages in 8 counties (districts) along the Jiulong River, Zhangjiang River, and Dongxi River basins in Zhangzhou City, Fujian Province were selected as survey sites during the period from November 2020 through March 2023, and snail and freshwater crabs were sampled from 1 to 3 streams and ditches neighboring residential areas in each village. Morphological identification of snails was performed according to the external morphological characteristics of collected snail shells, and the unidentified snail species sampled from the natural foci of paragonimiasis in Yunxiao County were subjected to se-quence analysis of the mitochondrial cytochrome oxidase 1 () gene. The crab species was identified by observing the morphological characteristics of the terminal segment of the first pleopod of male crabs, and cercariae and metacercariae were detected in collected snails.

Results: The shells of the unidentified snails sampled from the natural foci of paragonimiasis in Yunxiao County were approximately 50 mm in height and 18 mm in width, thick and solid, long tower cone-shaped, and had 8 to 10 whorls. gene sequence analysis identified the snail species as . A total of 6 freshwater snail species belonging to 5 genera within 3 families, identified 23 survey sites, including , and that belonged to the Family Pleurceridae, and that belonged to the subfamily Triculinae, Family Pomatiopsidae, and (Family Thiaridae), and 11 species of freshwater crabs belonging to 5 genera within 2 families were identified, including genus of , , and , genus of and , genus of and , and genus of and that belonged to the Family Potamidae, and genus of and (Family Parathelphusidae). In addition, the prevalence of cercariae infections was 0.08% (2/2 317) in from Danyan Village in Changtai District and 0.09% (1/1 039) in from Jinkeng Village in Yunxiao County, and the prevalence of metacercariae infections was 25.81% (8/31) in from Danyan Village in Changtai District, and 26.31% (5/19) in from Jinkeng Village in Yunxiao County, respectively.

Conclusions: There is a population diversity in the intermediate host snails and crabs along the Jiulongjiang River, Zhangjiang River, and Dongxi River basins in Bopingling Mountain, southern Fujian Province, and and are, for the first time, confirmed as the first intermediate hosts of .