Morphological and Mitochondrial Cox1-based Molecular Characterization of Rhipicephalus (Boophilus) microplus Infesting Cattle in Gujarat, India
D. B. Bhinsara *
Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Kamdhenu University, Navsari-396450, Gujarat, India.
J. B. Solanki
Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Kamdhenu University, Sardarkrushinagar- 385506, Gujarat, India.
Niranjan Kumar
Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Kamdhenu University, Navsari-396450, Gujarat, India.
M. Sankar
Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly (UP)-243122, India.
H. R. Parsani
Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Kamdhenu University, Navsari-396450, Gujarat, India.
I. H. Kalyani
Department of Veterinary Microbiology, College of Veterinary Science and Animal Husbandry, Kamdhenu University, Navsari, Gujarat-396450, India.
D. C. Patel
Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Kamdhenu University, Junagadh- 362001 Gujarat, India.
D. R. Prajapati
Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Kamdhenu University, Navsari-396450, Gujarat, India.
*Author to whom correspondence should be addressed.
Abstract
Rhipicephalus (Boophilus) microplus is a major one-host tick of cattle in tropical and subtropical zones and causes considerable economic losses through reduced livestock productivity and the transmission of tick-borne pathogens. Accurate species identification is important for epidemiological studies and the implementation of effective tick control strategies. The present study was conducted to characterise R. (B.) microplus collected from cattle in Gujarat, India, using morphological examination and mitochondrial cytochrome c oxidase subunit I gene analysis. Adult engorged female ticks were collected from cattle in five representative districts of Gujarat. Partial cox1 gene fragments (510 bp and 643 bp) were amplified by PCR from genomic DNA, and morphological identification was performed using standard taxonomic keys. Representative amplicons were sequenced and compared with sequences in GenBank using BLAST. Phylogenetic analysis was performed using the Neighbor-Joining method in MEGA 12. The expected cox1 fragments were successfully amplified by PCR from all representative isolates. Nucleotide identity of 99.13–99.78% was observed with authenticated R. microplus sequences available in GenBank. The Navsari isolate showed 99.56% similarity with the Hubli isolate (MH612840.1), whereas the Junagadh and Patan isolates showed 99.78% identity with Indian reference isolates. Phylogenetic analysis revealed that all Gujarat isolates clustered within the R. microplus lineage with isolates from India, Pakistan, China, Malaysia, and South Africa, indicating high genetic conservation and low mitochondrial DNA divergence. R. (B.) microplus was reliably identified through morphological observations and cox1 gene sequencing. The high sequence similarity and conserved phylogenetic relationships demonstrated the utility of the mitochondrial cox1 gene as a potential molecular marker for species identification and genetic characterisation, providing baseline information for epidemiological surveillance and future tick management programmes in Gujarat.
Keywords: Rhipicephalus (Boophilus) microplus, morphological identification, cox1 gene, molecular characterisation, phylogenetic analysis