RESUMO
Objective To investigate the population distribution of intermediate host snails and crabs of Paragonimus 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 (CO1) gene. The crab species was identified by observing the morphological characteristics of the terminal segment of the first pleopod of male crabs, and Paragonimus 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. CO1 gene sequence analysis identified the snail species as Sulcospira hainanensis. A total of 6 freshwater snail species belonging to 5 genera within 3 families, identified 23 survey sites, including Semisulcospira libertina, Paludomus zhangchouensis and S. hainanensis that belonged to the Family Pleurceridae, Tricula fujianensis and T. huaanensis that belonged to the subfamily Triculinae, Family Pomatiopsidae, and Melanoides tuberculata (Family Thiaridae), and 11 species of freshwater crabs belonging to 5 genera within 2 families were identified, including Sinopotamon genus of S. jianglense, S. pinheense, and S. zhangzhouense, Huananpotamon genus of H. planopodum and H. zhangzhouense, Nanhaipotamon genus of N. huaanense and N. longhaiense, and Minpotamon genus of M. nasicum and M. auritum that belonged to the Family Potamidae, and Somanniathelphusa genus of S. huaanensis and S. zhangpuensis (Family Parathelphusidae). In addition, the prevalence of P. westermani cercariae infections was 0.08% (2/2 317) in P. zhangchouensis from Danyan Village in Changtai District and 0.09% (1/1 039) in S. hainanensis from Jinkeng Village in Yunxiao County, and the prevalence of P. westermani metacercariae infections was 25.81% (8/31) in S. jianglense from Danyan Village in Changtai District, and 26.31% (5/19) in S. zhangzhouense 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 P. zhangzhouensis and S. hainanensis are, for the first time, confirmed as the first intermediate hosts of P. westermani.
RESUMO
The aim of the study was to investigate the population ecology of medical shellfish and the infection of An-giostrongylus cantonensis in Longhai ,Fujian Province ,China .Aquatic and terrestrial shellfish were collected in survey points according to different types of breeding grounds .Then ,lung-microscopy method was involved in the detection of the lung tis-sue in Ampullaria gigas .Other shellfishes were mashed to detect the third-stage larvae of Angiostrongylus cantonensis .Hom-ogenization and lung microscopy were compared in the detection of the larvae of A .cantonensis in Achatina snails .Factors re-lated to the environment and influence of shellfish hosts were also included .Results showed that 8 species of molluscans were found ,including Pila gigas ,Bellamya aeruginosa ,Bellamya lithophaga ,Melanoides tuberculata ,Achatina fulica ,Vag-inulus alte ,Philomycus bilineatus ,and Bradybaenasimilaris with 1 673 specimens in 27 survey points from 9 townships .The infectionratewas19.78% inaverage.TheinfectionrateinV.altewas56.63% (47/83);theinfectionratesforA.fulicaand P .gigas were 39 .32% (92/234) and 27 .14% (130/234) ,respectively .The infection rate of each survey point was closely re-lated to the distances from the residents living area .Morever ,A .cantonensis larvae were detected in M .tuberculata .Lung mi-croscopy and homogenization method detection rate was 87 .1%and 100 .0% ,respectively .The difference was statistically sig-nificant .In conclusion ,V .alte ,A . fulica and P .gigas were A . cantonensist infection dominant population . The infection rate was closely related to micro-ecological environment for all kinds of shellfish .M .tuberculata was the new host of A .can-tonensis .Lung microscopy method should not be used in the qualitative screening detection of A . f ulica infected with A .can-tonensist .