Molecular and morphological characterization of hard ticks (Acari: Ixodidae) infesting rodents in Southern Iran: evidence of a cryptic Haemaphysalis species.

Background

Hard ticks are important vectors of various zoonotic diseases. Identifying closely related tick species using morphological methods alone can be challenging. This study aimed to assess the taxonomic status of hard ticks infesting rodents in southern Iran using morphological and molecular approaches.

Methods

Ticks were collected from the ear bases and rears of rodents and identified morphologically. Genomic DNA was extracted, and the cytochrome oxidase subunit 1 (COX1) and internal transcribed spacer 2 (ITS2) genes were amplified via polymerase chain reaction (PCR). Sequencing and phylogenetic analyses were performed using assembled DNA sequences and reference sequences from GenBank.

Results

A total of 62 rodents from seven species were examined. Collected ticks were identified as Rhipicephalus turanicus and Haemaphysalis spp. Phylogenetic analysis revealed that the Haemaphysalis samples were genetically distinct from 29 congeneric species recorded in the Barcode of Life Data System (BOLD) and GenBank. No sequence matches were found with known Haemaphysalis species in Iran, except for H. caucasica and H. aponommoides, which lack sequence data in these databases.

Conclusions

This study represents the first molecular characterization of Haemaphysalis and Rhipicephalus ticks infesting rodents in Iran. Our findings confirm the presence of Rhipicephalus turanicus on Rattus species. More significantly, we identified a distinct Haemaphysalis lineage parasitizing Calomyscus cf. bailwardi, a rodent endemic to the Zagros Mountains. The considerable genetic divergence observed in both the COX1 and ITS2 genes suggests that this Haemaphysalis lineage may represent a cryptic species or a unique ecotype adapted to this specific host and geographic location.