Molecular characterization of tick genera Haemaphysalis, Ixodes, and Amblyomma in Korea

Abstract

Ticks are important ectoparasites that serve as key vectors of various pathogens, posing significant risks to both human and animal health. In this study, 3 genera and 5 species of ticks, including Haemaphysalis longicornis, H. flava, H. doenitzi, Ixodes nipponensis, and Amblyomma testudinarium, were analyzed both morphologically and molecularly. Morphological identification was conducted using established taxonomic keys, followed by molecular characterization through analysis of complete cytochrome c oxidase subunit 1 (cox1, 1,539 bp) and mitochondrial 16S rDNA (1,191-1,215 bp), and nuclear 18S rDNA (1,812-1,816 bp). Phylogenetic and pairwise distance analyses demonstrated that all 3 genes were effective for genus identification; cox1 and mitochondrial 16S rDNA were more effective than 18S rDNA in species identification. Additionally, this study is the first to identify H. doenitzi in the Korean mainland via molecular characterization. These results may serve as reference data for the molecular identification of tick species.

Keywords: Amblyomma; Haemaphysalis; Ixodes; cox1; mitochondrial 16S rDNA; nuclear 18S rDNA.

Fig. 1

Phylogenetic analysis of ticks based on complete (A) cytochrome c oxidase subunit 1, (B) mitochondrial 16S rDNA, and (C) nuclear 18S rDNA. The maximum-likelihood method with 500 bootstrap replications was used to construct the phylogenetic tree. The GenBank accession numbers, followed by species names and their corresponding countries, are indicated. Arrows indicate the sequences obtained in this study.