An Assessment of the Molecular Diversity of Ticks and Tick-Borne Microorganisms of Small Ruminants in Pakistan.

ABSTRACT

This study investigated ticks and tick-borne microorganisms of small ruminants from five districts of the Federally Administered Tribal Area (FATA) of Pakistan. Morphological (n = 104) and molecular (n = 54) characterization of the ticks revealed the presence of six ixodid ticks Rhipicephalus (Rh.) haemaphysaloides, Rh. microplus, Rh. turanicus, Haemaphysalis (Hs.) punctata, Hs. sulcata and Hyalomma anatolicum. Phylogenetic analyses of nucleotide sequence data for two mitochondrial (16S and cytochrome c oxidase 1) and one nuclear (second internal transcribed spacer) DNA regions provided strong support for the grouping of the six tick species identified in this study. Microfluidic real-time PCR, employing multiple pre-validated nuclear and mitochondrial genetic markers, detected 11 potential pathogens and endosymbionts in 72.2% of the ticks (n = 54) tested. Rickettsia (R.) massiliae was the most common pathogen found (42.6% of ticks) followed by Theileria spp. (33.3%), Anaplasma (A.) ovis and R. slovaca (25.9% each). Anaplasma centrale, A. marginale, Ehrlichia spp., R. aeschlimannii, R. conorii and endosymbionts (Francisella- and Coxiella-like) were detected at much lower rates (1.9-22.2%) in ticks. Ticks from goats (83.9%) carried significantly higher microorganisms than those from sheep (56.5%). This study demonstrates that ticks of small ruminants from the FATA are carrying multiple microorganisms of veterinary and medical health significance and provides the basis for future investigations of ticks and tick-borne diseases of animals and humans in this and neighboring regions.