Ticks are obligatory haematophagus arthropods which pose a significant medical and veterinary health risk on a global scale owing to the direct harm they impose on their hosts and just because they serve as vectors for a wide range of human and animal pathogens. Dairy industry in particular suffers huge economic losses because of ticks and tick-borne diseases (TTBDs) in tropical and sub-tropical countries including India. Therefore it is crucial to monitor and maintain surveillance of the key vector species in order to understand their epidemiology, distribution or abundance in a particular geographical area. This is not only provides knowledge about the vector but also help in the assessment of the vector-borne diseases. This is crucial when discussing how climate change affects vector populations and the dynamics of the transmission of vector-borne diseases (Medlock et al., 2013; Semenza & Paz, 2021).
The direct and indirect impacts of TTBDs are well documented (Ghosh and Nagar, 2014; Hurtado and Giraldo-Ríos, 2018). At least 106 species have been reported from India (Ghosh et al., 2007) out of the 904 valid tick species identified globally (Ajith Kumar et al., 2018). Of the reported tick species, Rhipicephalus microplus and Hyalomma anatolicum are the most widely distributed economically important tick species infesting Indian cattle, sheep, goat, buffaloes. These are also known to transmit Babesia bigemina, Anaplasma marginale, Theileria annulata, T. buffeli, T. lestoquardi (Ghosh et al., 2007, Ghosh and Nagar, 2014). Moreover, Hyalomma ticks are also known for maintenance and transmission of Crimean Congo Hemorrhagic fever (CCHF) virus to humans which is frequently reported in India (Ghosh and Nagar, 2014; Mourya et al., 2019) and from other parts of the world (Boulanger et al., 2019; Shahhosseini et al., 2021). However, till now, the distribution of these tick species in this region is poorly known and not well characterized.
Although, the body of ticks is not distinctly divided as other arthropods like insects, but they can be divided into three regions: anterior head and mouth region called Gnathosoma, middle leg region called Podosoma and posterior region that includes anus, festoon and other structures called Opisthosoma. Various anatomical features are available on both dorsal and ventral sides of the tick. The variations in these structures are used for identification purposes. They also have different life stages like eggs, larvae, nymphs and adults of different size and morphological features (Taylor et al., 2015).
Traditional taxonomical identification of ticks was based on the morphological features of adult ticks observed under a microscope. Despite the significance of morphological characterization as a fundamental component of tick identification, its application is restricted to the presence of entomological expertise, the availability of dichotomous keys or comparative illustrations, morphologically similar taxa, tick specimen integrity, or engorgement status, especially for immature stages (Senbill et al., 2022; Well and Stevens, 2008). Additionally, this demands for extensive morphological and taxonomic expertise and experience. In such a case, complementary tools for precise tick identification are provided by molecular methods based on the amplification and sequencing of mitochondrial and/or ribosomal DNA fragments (Brahma et al., 2014; Ernieenor et al., 2017). Cytochrome c oxidase-1 (COX1) gene is most frequently used marker and reported first choice for tick species identification (Lv et al., 2014; Ernieenor et al., 2017). The molecular methods like PCR amplification of suitable fragment of genome followed by sequence analysis are the usual and recommended methods for the precise identification of an organism (Amendt et al., 2004).
There are only very few reports on the morphological and molecular characterization of common bovine tick species R. microplus and Hy. anatolicum from India (Low et al., 2015; Roy et al., 2018; Kandi et al., 2022; Amrutha et al., 2023). Particularly, information are lacking regarding the status of the common bovine tick, Hy. anatolicum and R. microplus, from western India in public domain. Accordingly, in the present investigation both traditional and molecular approaches were used for the identification and characterization of ticks infesting the cattle in western region of India.