title: Morphological Characteristics and Phylogenetic Trends of Trematode Cercariae in Freshwater Snails from Nakhon Nayok Province, Thailand.
abstract: The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual snails were examined for parasitic infections. The results showed that 12 snail species were found to host larval stages of trematodes with an overall prevalence of 4.7%. The infected specimens included 7 types at the cercarial stage; cercariae, megalurous cercariae, echinostome cercariae, furcocercous cercariae, parapleurolophocercous cercariae, virgulate cercariae, and xiphidiocercariae. Regarding molecular identification, ITS2 sequence data of each larval trematode were analyzed, and a dendrogram was constructed using the neighbor-joining method with 10,000 replicates. The dendrogram was separated into 6 clades (order/family), including Echinostomatida/Echinostomatidae, Echinostomatida/Philophthalmidae, Opisthorchiida/Heterophyidae, Plagiorchiida/Prosthogonimidae, Plagiorchiida/Lecithodendriidae, and Strigeatida/Cyathocotylidae. These findings were used to confirm morphological characteristics and evolutionary trends of each type of cercariae discovered in Nakhon Nayok province. Furthermore, this investigation confirmed that the ITS2 data of cercariae could be used to study on phylogenetic relationships or to determine classification of this species at order and/or family level when possible.
authors.affiliation: Parasitology Research Laboratory, Department of Biology, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand.|Center of Excellence in Animal, Plant and Parasitic Biotechnology, Srinakharinwirot University, Bangkok 10110, Thailand.
authors.forename: Thapana
authors.initials: T
authors.lastname: Chontananarth
authors.affiliation: Parasitology Research Laboratory, Department of Biology, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand.|Center of Excellence in Animal, Plant and Parasitic Biotechnology, Srinakharinwirot University, Bangkok 10110, Thailand.
authors.forename: Thanawan
authors.initials: T
authors.lastname: Tejangkura
authors.affiliation: Parasitology Research Laboratory, Department of Biology, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand.
authors.forename: Napat
authors.initials: N
authors.lastname: Wetchasart
authors.affiliation: Parasitology Research Laboratory, Department of Biology, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand.
authors.forename: Cherdchay
authors.initials: C
authors.lastname: Chimburut
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005618:Fresh Water; D008853:Microscopy; D010802:Phylogeny; D015995:Prevalence; D017422:Sequence Analysis, DNA; D012908:Snails / Q000469:parasitology*; D013785:Thailand; D014200:Trematoda / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D018509:DNA, Helminth; D021903:DNA, Ribosomal Spacer
keywords: ITS2; Nakhon Nayok province; Thailand; cercaria; phylogenetic relationship; prevalence; snail; trematode