UTTAR PRADESH JOURNAL OF ZOOLOGY

A survey was conducted in key mithun-inhabiting areas of northeastern states, viz. Arunachal Pradesh, Nagaland, Mizoram, and Manipur, to study Rhipicephalus Spp. tick infestation prevalence and its associated pathological effects on Mithun health. A total of 1778 animals were randomly screened, and 27 tick isolates were collected for identification. Molecular identification was carried out using PCR amplification of the mitochondrial COI gene and the ITS-2 region, followed by DNA sequencing. The identified tick species were confirmed as Rhipicephalus microplus. Tick infestation showed seasonal variation, with the highest concentration during the monsoon and pre-monsoon period. The study recorded a 50.64% incidence rate with a tick index of 2.08. Gross examination of tick-infested adult mithun showed symptoms of hyperkeratinization, alopecia, focal dermatitis, crust and scab formation, weakness, loss of body condition, and even death. Histopathology revealed exfoliation, hyperkeratosis, oedema, necrosis, and collagen fibre disorientation, along with cellular infiltrates in the corneum and dermis. Ultrastructural analysis showed cell death, vacuolation, inflammatory infiltrates, necrotic cells, and organelle disorganization in the epidermis. The study highlights the significant burden of Rhipicephalus microplus infestation in mithun populations of Northeast India, demonstrating marked seasonal influence and dermal pathology. The findings highlight the need for timely surveillance and integrated tick-control strategies to safeguard mithun health and productivity.