Morphological and molecular identification of the brown dog tick, Rhipicephalus sanguineus sensu lato in Tamil Nadu

AbstractThe objective of this work was to identify the Rhipicephalus sanguineus species prevalent in dogs in Tamil Nadu by using polymerase chain reaction assay followed by sequencing. In this study, 300 semi-engorged ticks were collected each from three different agro-climatical zones such as north (Chennai), west (Namakkal) and south (Madurai) zones of Tamil Nadu, India. All these ticks were identified as R. sanguineus based on morphological keys. Five ticks from each place were dissected out to separate the midgut and the genomic DNA was extracted. Polymerase chain reaction amplification and sequencing were carried out to obtain a 400 bp fragment of the mitochondrial 12S rDNA sequences. The nucleotide sequence showed homology of 99.71% to the sequences of other isolates of R. sanguineus sensu lato available in the GenBank. The analysis confirmed the identity of ticks from three agro-climatical zones of Tamil Nadu as R. sanguineus sensu lato, which has been reclassified as R. linnaei.