Morphological and molecular characterization of Ixodid ticks infesting cattle in western India

Abstract

Ticks are well known for its potential as vectors second only to mosquitoes. They are considered to be the important vectors of many disease-causing pathogens in domesticated animals as well as in humans. For any strategic control of pest or pathogens, their identification and epidemiological knowledge is very much essential. Accordingly, a total of 860 cattle were examined from more than 100 farms, Gausalas and Panjrapoles in four districts of western India where 46.05% (n=396) cattle were found to be infested with ticks. The collected tick samples were examined under stereo-zoom microscope and ticks were identified morphologically as either Hyalomma anatolicum or Rhipicephalus microplus. Which was further confirmed by PCR assay targeting cytochrome c oxidase subunit I (cox1) gene followed by sequence analysis. The interspecific divergence between current isolates of Hy. anatolicum and R. micropluswas 20.9%. The wider range of intraspecific divergence was recorded in R. microplus (0 - 11.7%) compared to Hy. anatolicum (0 -1.6%), globally. In phylogenetic analysis Indian isolates of R. microplusclustered with R. microplus clade C. Additionally, a more applicable test, In-silico followed by PCR-RFLP restriction enzyme analysis, was employed to differentiate between the two tick species. Among the total 396 tick infested cattle, significantly higher (p<0.001) number of cattle were found to be infested with H. anatolicum (70.96%, n=281) as compared to R. microplus (51.77%, n=205) whereas, 22.73% (n=90) cattle were found to be infested with mixed tick infestation of both. The study indicate that Hy. anatolicum and R. microplus ticks of western region of India is same as other parts of country.