Genetic differentiation of Anisakis species (Nematoda:Anisakidae) in marine fish Priacanthus tayenus from Gulfof Thailand

摘要

Members of the genus Anisakis are parasitic nematodes of the family Anisakidae.They are potential zoonotic parasites, causing anisakiasis in humans who consume raw orundercooked seafood (fish or squid) infected with the larvae of this nematode. In the presentstudy, anisakid nematodes collected from the marine fish Priacanthus tayenus (Purplespottedbig-eye) caught from the Gulf of Thailand were examined morphologically andcharacterized genetically by DNA sequence analysis. Sequence data from the mitochondrialcytochrome c oxidase subunit II (mtDNA cox2) gene were used to identify these nematodesto species level and to evaluate the phylogenetic relationship among various taxa. All the 15third-stage larvae of Anisakis nematodes investigated in this study belonged to the samegenetic lineage as the A. typica species complex (named here as A. typica sp. T – T forThailand). Eight mtDNA cox2 haplotypes were revealed in the 15 isolates of this Anisakisfrom Thailand. The mtDNA cox2 haplotypes of A. typica sp. T from Thailand were geneticallydistinct from those of the A. typica sensu stricto. Taxonomic description of this A. typica sp.T as a distinct species however awaits the availability of adult specimens.