DNA barcoding identifies hard tick (Acari: Ixodidae) species infesting domesticated animals in Tamil Nadu, South India

IF 1.6 Q3 PARASITOLOGY

Veterinary parasitology, regional studies and reports Pub Date : 2026-02-01 Epub Date: 2026-01-14 DOI:10.1016/j.vprsr.2026.101425

Krishnamoorthy Nallan , Veerapathiran Ayyavu , Elango Ayyanar , Balaji Thiruppathi , Ramkumar Ramalingam , Manju Rahi , Paramasivan Rajaiah

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Abstract

The diverse and vast ecological landscapes of India support a rich diversity of ticks, many of which are known vectors of a wide range of pathogens. Accurate identification of tick species is critical for incriminating specific vectors involved in pathogen transmission. The present study aims to generate DNA barcodes using molecular markers for the identification of tick fauna from Tamil Nadu, southern India, where molecular taxonomic studies remain limited. A total of 57 specimens representing 12 different species were subjected to DNA barcoding using cytochrome c oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2). Polymerase chain reaction (PCR) assays targeting the COI gene were successful in 7 species from four genera: Haemaphysalis, Hyalomma, Rhipicephalus, and Amblyomma. Similarly, 6 species from two genera, Rhipicephalus and Haemaphysalis, were successfully amplified using the ITS2 gene marker. Further analysis of inter-species diversity based on COI markers across eight species revealed better resolution compared to ITS2 markers. Inter-species distances of 16%, 15%, 14%, and 13% were recorded among four Rhipicephalus species using both markers, with the highest genetic divergence (16%) observed between R. microplus and R. sanguineus. The lowest inter-species divergence was 6% (COI) and 1% (ITS2), observed between R. microplus and R. annulatus. To our knowledge, this study provides the first DNA barcode records based on COI for Hyalomma anatolicum and Amblyomma integrum, and based on ITS2 for Rhipicephalus annulatus and Haemaphysalis intermedia from India. In conclusion, for four Rhipicephalus and two Haemaphysalis species, the dual-marker barcoding approach effectively complements conventional identification methods by resolving ambiguities arising from morphological similarities among tick species in this region.

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DNA条形码鉴定了在印度南部泰米尔纳德邦感染家畜的硬蜱（蜱螨：伊蚊科）物种

印度多样而广阔的生态景观支持着丰富多样的蜱虫，其中许多是已知的各种病原体的载体。蜱类的准确鉴定对于确定参与病原体传播的特定媒介至关重要。本研究旨在利用分子标记生成DNA条形码，用于鉴定来自印度南部泰米尔纳德邦的蜱动物群，那里的分子分类学研究仍然有限。利用细胞色素c氧化酶亚基I （COI）和内转录间隔段2 （ITS2）对12个不同物种的57个标本进行了DNA条形码分析。聚合酶链反应（PCR）成功检测了血蛉、透明瘤、鼻头瘤和羊瘤4属7种COI基因。同样，利用ITS2基因标记成功扩增到了头蜱和血蜱两属的6种。基于COI标记对8个物种的种间多样性进行进一步分析，发现与ITS2标记相比，COI标记的分辨率更高。两种标记分别测定了4种鼻头属的种间距离，分别为16%、15%、14%和13%，其中微头属和血头属的遗传差异最大（16%）。种间差异最小的分别是微加和环麻，COI和ITS2分别为6%和1%。据我们所知，本研究提供了首个基于COI的anatolicum和Amblyomma integrum的DNA条形码记录，以及基于ITS2的来自印度的Rhipicephalus annulatus和haemaphyysalis intermedium的DNA条形码记录。综上所述，对于4种鼻头蜱和2种血蜱，双标记条形码方法解决了该地区蜱类形态相似性引起的歧义，有效地补充了传统的鉴定方法。

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来源期刊

Veterinary parasitology, regional studies and reports Multiple-

CiteScore

2.90

自引率

7.10%

发文量

126

审稿时长

97 days

期刊介绍： Veterinary Parasitology: Regional Studies and Reports focuses on aspects of veterinary parasitology that are of regional concern, which is especially important in this era of climate change and the rapid and often unconstrained travel of people and animals. Relative to regions, this journal will accept papers of the highest quality dealing with all aspects of disease prevention, pathology, treatment, epidemiology, and control of parasites within the field of veterinary medicine. Also, case reports will be considered as they add to information related to local disease and its control; such papers must be concise and represent appropriate medical intervention. Papers on veterinary parasitology from wildlife species are acceptable, but only if they relate to the practice of veterinary medicine. Studies on vector-borne bacterial and viral agents are suitable, but only if the paper deals with vector transmission of these organisms to domesticated animals. Studies dealing with parasite control by means of natural products, both in vivo and in vitro, are more suited for one of the many journals that now specialize in papers of this type. However, due to the regional nature of much of this research, submissions may be considered based upon a case being made by the author(s) to the Editor. Circumstances relating to animal experimentation must meet the International Guiding Principles for Biomedical Research Involving Animals as issued by the Council for International Organizations of Medical Sciences (obtainable from: Executive Secretary C.I.O.M.S., c/o W.H.O., Via Appia, CH-1211 Geneva 27, Switzerland).