Molecular phylogeny of tick species in naturally infested cattle

Background: Tick is the second largest vector of diseases, which infests many domestic and wild animals resulting in great economic losses due to morbidities and mortalities. Aim: Clinical investigation of naturally infested cattle found in Al-Diwanyah city (Al-Qadisiyah, Iraq), morphological diagnosis of ticks’ species, and molecular phylogeny of local isolates to identify its identity to global NCBI-GenBank isolates. Materials and methods: Totally, 438 cattle of different ages and sexes were examined clinically during June-July (2024) to identify and collection of tick samples to be examined traditionally based on morphological characterization. Then, the tick samples were examined molecularly using the conventional PCR, and some of positive samples were sequenced, submitted in the NCBI-database and analysed phylogenetically using the MEGA-11 Software.Results: A total of 72.37% of study cattle were infested clinically with ticks that existed high significantly in hind-limbs (97.48%) and ears (91.17%), but reduced in back (14.51%) when compared to other body parts including neck (79.2%), udder (71.92%), perineum (52.68%), and forelimbs (35.96%). Regarding age, the prevalence rate of tick was increased significantly in cattle aged 6-9 years (96.72% (59/61)] and cattle aged ≥ 10 years (96.3%) and decreased significantly in cattle aged ≤ 1 year (15.22%) in comparison with those aged 2-5 years (84.5%). Among the positive infested animals, ticks were detected significantly in cattle aged 2-5 years (68.77%) and decreased in those aged ≤ year (4.42%) and ≥ 10 years (8.2%) when compared to cattle aged 2-5 years (18.61%). Based on their morphology, microscopic characteristic suspected largely that all collected samples were hard ticks and belong to Hyalomma anatolicum. Targeting the 18S rRNA gene, the PCR results confirmed that all samples are belonged to H. anatolicum. The sequence data of 11 local isolates were named as “Ghirban-Iraq1 to Ghirban-Iraq11”, and submitted in the NCBI-GenBank database under the accession numbers “PV615532.1 to PV615542.1”. Phylogenetic analysis of study isolates revealed its significant identity to the global NCBI-BLAST Chinese H. anatolicum XJ076 isolate (JX051052.1) at a similarity ranged 98.65-99.87% with presence of mutation / changes at 0.017-0.0011%.Conclusion: Hard ticks, especially H. anatolicum, remain a high prevalent ectoparasite in Iraqi cattle causing severe economic losses due to morbidities and mortalities. The combination of traditional morphological characteristics and molecular phylogeny revealed a high efficacy in identification of tick species. Therefore, we recommended to collection the ticks from all field animals to investigate the tick species based on their morphology, and demonstrating their species and origins following the molecular phylogeny due to the definite role of this external parasite in transmission of various diseases to both animals and humans.