Morphological and Molecular Identification of Hard Ticks in Hainan Island, China.

Ticks are small, blood-sucking arachnids, known vectors of various diseases, and found throughout the world. They are distributed basically in almost all regions of China. At present, there is not much information regarding tick species on Hainan Island. They were subjected to morphological identification and imaging on an individual basis. Molecular phylogenetic analyses, based on and rRNA genes, were utilized to identify the species and determine their approximate phylogenetic origin and genetic diversity. The genomic DNA of tick species was extracted, and cytochrome oxidase subunit 1 () and ribosomal RNA (rRNA) genes were amplified and sequenced. The identification of five tick species, namely , , , and , was carried out by morphological analysis. When employing the and rRNA phylogenetic tree, all isolates of from Hainan Island were classified as clade A and B, respectively. was recognized as a member of the tropical lineage by phylogenetic analysis on the and rRNA genes. Three phylogenetic groups of were recognized and found to be related closely to strains from China. and formed one phylogenetic group, presumably from tick strains prevalent in Japan and China. The haplotype network analysis indicated that is classed into 26 and 6 haplotypes, which correspond to and rRNA gene assemblages, respectively. In addition, four haplotypes were detected in . This is the first evidence that suggests genetic diversity, host range and geographical distribution of hard ticks in Hainan Island, China.