The present study was conducted to determine the prevalence of hard tick infections in domestic animals of Vellore district Tamil Nadu from October 2018 to December 2019. We have collected 541 tick samples (50 from this study 9 from Gen bank) nine species and two genera of the hard tick. The mitochondrial COI region of samples were collected in Vellore district. We successfully amplified gene sequence using PCR. COI gene, Rhipicephalus microplus, Hylomma margintum 18SrRNA, Rhipicephalus sp, Haemaphasalis sp. The belongs to the genus of hard tick (Ixodida). Among these, three different species were identified. Of them, Rhipicephalus sp, Haemaphasalis sp, Hylomma sp from 18SrRNA, two different species were identified in Rhipicephalus microplus, Hylomma margintum from the Cytochrome oxidase 1(COI) gene.
Ticks have long been recognised for their medical and veterinary value. The dispersion and availability of tick species that infest cattle varies greatly by region. The current study investigates the prevalence of tick infestations in a domestic animal from Vellore. Infections with Rhipicephalus (Boophilus) sp., Hyalomma sp., and Haemaphysalis sp., as well as mixed infections, were found to be 32.25 percent, 12.58 percent, 3.22 percent, and 6.12 percent, respectively . This study's findings were consistent with previous reports from various parts of India and abroad [22, 23, 24].
A reliable database is the foundation of barcodes, with rows formed from expertly identified and confirmed models. This database contains rows of published and supported feeders in the BOLD system. Furthermore, studies on tick phylogeny provide a high level of reliability for COI, 16S, and 18S sequences because these sequences originated from models identified by tick experts . Because COI is used to identify birds, fish, and arthropods, it is believed that this gene can provide better resolution to the predator on the scale; however, the number of COI sequences published at BOLD and GenBank is 325 from 66 species, which is insufficient to establish a DNA barcoding system. To complete the COI, it is best to add more genetic sites to the DNA barcoding system. 16S is a popular marker for determining tick evolution and biogenetic relationships. To date, the number of ticks in the 16S released at GenBank exceeds the COI by more than twofold, totalling 647 out of 129 species. According to our findings, they are effective at tick discrimination at the COI and 16S species levels .
Previous research has shown that 18S is generally protected. However, the full length of the 18S is 1800 bp, which exceeds the upper limit for DNA barcode length. Considering the length of universal primers and PCR products for the 18S, a fraction of 780 bp was studied. In addition, the neighbor joining tree dependent on 18S gave critical topological goal at the genera level, and this outcome was not totally predictable with past information. Possible explanations include a fragment of 780 bp, but the full length of the 18S has not been used in terms of NJ analysis; the phylogenetic tree was based on the NJ method but not on other bioinformatics methods .
Tick specimens collected from domestic animals were taxonomically classified into two genera, Rhipicephalus and Haemaphasalis, identified at the Institute of Vector Control and Zoonoses in Hosur (IVCZ). The two species mentioned above could be classified as a single family, Ixodidae. Miranpuri and Singh (1978) has reported ixodid ticks on domestic animals are common in several other Indian states, including Assam, Karnataka, and Tamil Nadu. [28, 29, 30].
Some of the Rhipicephalus species studied here (e.g., R. sanguineus s.l., R. sp. I, and R. sp. II) shared striking morphological similarities. However, morphological examination of the main characters (for example, female genital opening shape, male adenal plate shape, squat stop pattern, and spiral plate shape in both sexes) assisted us in distinguishing these species. Importantly, adult measurements are known to be ineffective for distinguishing Rhipicephalus species. However, given the differences found here for some specific characters (e.g., adanal plate length / width ratio), future research should better assess the utility of morphometric analysis in distinguishing between Rhipicephalus adults and immature conditions. Our genetic analyses confirmed the separation of all the Rhipicephaline species examined by supporting the presence of distinct clades. High genetic integration has been discovered within the R. microplus tick population, regardless of geographical appearance. It was also hypothesised based on intra- and interspecific nucleotide variations in mitochondrial DNA that clearly defined the molecular identities of Rhipicephalus sp., R.microplus, Haemaphysalis sp., and Hyalomma margintum.
Finally, the current study discusses the results of a survey on the species diversity of ixodid ticks infesting Vellore's domestic animals. Natural tick infestations have been observed on host animals such as cows, goats, dogs, and sheep. This demonstrates that tick infection is a significant impediment to the proper development and well-being of the important domestic animals in Tamil Nadu's Vellore district.