Thumbnail Image

Kerala Veterinary and Animal Sciences University, Wayanad

Browse

20181
Reset filters
Subject: Veterinary Parasitology × Author: AMRUTHA B.M. × End date: 2019 × Start date: 2010 ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    MOLECULAR CHARACTERISATION OF RHIPICEPHALUS (BOOPHILUS) ANNULATUS AND R. (B.) MICROPLUS USING MITOCHONDRIAL CYTOCHROME C OXIDASE SUBUNIT 1 (COI) GENE AND SECOND INTERNAL TRANSCRIBED SPACER (ITS2)
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD, 2018) AMRUTHA B.M.; AJITH KUMAR K. G.
    The present study was carried out to differentiate closely related Rhipicephalus (Boophilus) species like R. (B.) microplus and R. (B.) annulatus and to characterise these species using molecular tools. Molecular tools like polymerase chain reaction (PCR), sequencing, phylogenetic analysis and divergence analysis were adopted. When a total of 279 cattle were screened for presence of infestation with hard ticks from different geographical locations of Kerala and Karnataka, 213 animals were identified as infested. In Kerala, R. (B.) annulatus was the predominant species (54.26 per cent) followed by H. bispinosa (25.58 per cent), R. (B.) microplus (12.40 per cent) and R. haemaphysaloides (5.42 per cent). R. (B.) microplus was the predominant species (77.10 per cent) in Karnataka followed by H. bispinosa and R. haemaphysaloides with 18.07 per cent and 4.81 per cent prevalence rates respectively. Morphologically identified R. (B.) microplus (13 numbers) and R. (B.) annulatus (14 numbers) were used for the molecular characterization using cytochrome c oxidase subunit 1 (COI) and internal transcribed spacer (ITS2) molecular markers. Some of the R. (B.) microplus male ticks showed presence of a spur in the ventral surface of palpal article I similar to that seen in R. (B.) australis males. Dorsal setae were short and medial alloscutal setae were arranged in 2-3 rows in R. (B.) microplus female ticks. All the PCR products were sequenced and BLAST analysis was performed for confirmation of the species. The phylogenetic analysis of R. (B.) microplus isolates from both Kerala and Karnataka using COI classified them into R. (B.) microplus clade C, comprising R. (B.) microplus isolates from Haryana, India and other neighbour countries like Pakistan, Myanmar and Bangladesh. R. (B.) annulatus isolates from Kerala clustered with other R. (B.) annulatus isolates from Chennai, India, Iraq, Israel and Romania. The phylogenetic tree based on ITS2 failed to distinguish closely related R. (B.) microplus complex as R. (B.) microplus and R. (B.) annulatus isolates were clustered together. Divergence analysis was done further to differentiate R. (B.) microplus and R. (B.) annulatus. The COI gene showed greater value (7.9 per cent) for interspecific divergence compared to ITS2 (3.6 per cent). Thus COI was identified as a better marker in resolving interspecific divergence in comparison to ITS2. The intraspecific divergence for R. (B.) microplus was higher compared to R. (B.) annulatus. When R. (B.) microplus isolates of South India were compared with isolates of R. (B.) microplus clade A, B and C, higher divergence was observed with clade A (11.9 per cent) followed by clade B (7.4 per cent). Least divergence was observed against R. (B.) microplus clade C (2.3 per cent). Thus, the results of the present study revealed that Indian isolates of R. (B.) microplus clade C sensu lato was phylogenetically distant from true R. (B.) microplus clade A sensu stricto.