Molecular identification and phylogenetic characterization of Rhipicephalus (Boophilus) microplus from the coastal region of Bangladesh based on the mitochondrial cox1 gene

Abstract

Objectives: The Rhipicephalus (Boophilus) microplus is an economically important ectoparasite of livestock that transmits several hemoprotozoan pathogens, causing substantial economic losses. This study focuses on the phylogenetic analysis of the R. microplus tick using the mitochondrial cytochrome c oxidase subunit I (cox1) gene. Materials and Methods: Genomic DNA was extracted from 20 ticks collected from cattle in Nalchity upazila, Jhalokati district, a coastal region of Bangladesh. All 20 extracts were PCR-positive for cox1; four representative specimens were selected for Sanger sequencing due to resource constraints. Results: As all four sequences were identical, a single representative 606-bp sequence (ON545855) was deposited in GenBank. A maximum-likelihood phylogenetic tree constructed from the Jhalokati sequence and comparator R. (Boophilus) sequences from GenBank placed the isolate within a regional South and Southeast Asian R. microplus lineage that also includes previously reported sequences from Bangladesh, India, Pakistan, and Malaysia. Several sequences within this lineage originate from hosts other than cattle, including buffalo, sheep, dogs, and bears, consistent with the broad host range previously documented for R. microplus. Our data support phylogenetic affinity to these host records rather than demonstrating multi-host infestation within the present study population. Conclusions: This study provides the first cox1-based molecular record of R. microplus from the Jhalokati district of the coastal region of Bangladesh and situates it within the regional South/Southeast Asian phylogeny, offering a basis for future multi-host and pathogen-inclusive surveillance in coastal Bangladesh within a One Health framework.