title: Molecular phylogeny and host specificity of the larval Eustrongylides (Nematoda: Dioctophmidae) from freshwater fish in China.
abstract: The nematodes Eustrongylides spp. collected from different fish species in China were examined for their intra- and interspecific evolutionary variations using the molecular markers mitochondrial cytochrome oxidase c subunit 1 (COI) gene and internal transcribed spacer (ITS) rDNA regions. The phylogenetic analysis indicated that Eustrongylides species are divided into 3 well-supported clades. The ITS divergence between the clades suggested that clades 2 and 3 might represent the same species, whereas clade 1 represent another cryptic species. The host specificity of these nematodes was analyzed according to prevalence data, host range, and phylogenetic information. Clade 1 was found in 4 fish species, i.e., Odontobutis obscurus, Silurus asotus, Culter mongolicus, and Acanthogobius flavimanus, but was predominant in the 2 perciform species, O. obscurus and A. flavimanus. Clade 2 was found in 3 fish species, Monopterus albus, Channa argus, and Channa asiatica, but was predominant in M. albus, reported to feed primarily on oligochaetes, the first intermediate host of Eustrongylides sp. Clade 3 was found in 9 species, but its low prevalence suggests accidental infection in all species. Although the larval nematode presented low host specificity, it exhibited some host preference.
authors.affiliation: The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, and Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Xiong
authors.forename: Wen X
authors.initials: WX
authors.lastname: Li
authors.forename: Shan G
authors.initials: SG
authors.lastname: Wu
authors.forename: Hong
authors.initials: H
authors.lastname: Zou
authors.forename: Gui T
authors.initials: GT
authors.lastname: Wang
mesh_terms: D000465:Algorithms; D000818:Animals; D001483:Base Sequence; D001499:Bayes Theorem; D002681:China / Q000453:epidemiology; D018509:DNA, Helminth / Q000737:chemistry; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D017159:Dioctophymatoidea / Q000145:classification / Q000235:genetics* / Q000502:physiology; D003576:Electron Transport Complex IV / Q000235:genetics; D017189:Enoplida Infections / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D005393:Fish Diseases / Q000453:epidemiology / Q000469:parasitology*; D005399:Fishes; D058507:Host Specificity; D007814:Larva / Q000033:anatomy & histology / Q000145:classification; D016013:Likelihood Functions; D008390:Markov Chains; D008969:Molecular Sequence Data; D010802:Phylogeny; D015995:Prevalence; D016415:Sequence Alignment
chemical_list: D018509:DNA, Helminth; D021903:DNA, Ribosomal Spacer; D003576:Electron Transport Complex IV