Molecular Incidence of Theileriosis in Morphologically Identified Hard Ticks

Abstract

The current study aims for molecular detection of theileriosis caused by Theileria annulata in hard ticks (Hyalomma anatolicum) using the conventional PCR. A total of 200 buffaloes existed in different areas in Wasit province (Iraq) were subjected to collection the tick samples during April to July (2023) to be examined morphologically and molecularly. Among study cattle examined grossly, 74% were found positives for presence of tick infestation. Regarding distribution of ticks on different bodily parts of study buffaloes, significant higher infestation of ticks was seen in udder (26.9%) and perineal region (23.1%); while, significant lowering was seen in forelimb (9.76%) and neck (9.76%); when compared to ear (15.48%) and hindlimb (18.57%). Concerning the month of samples collection, the findings showed a significant increase (P<0.0436) in prevalence of ticks in June (80%) and July (86%) and significant decrease in April (58%) when compared to May (72%). Based on their morphological characteristics, microscopic examination of collected ticks referred that all samples were hard ticks belongs to Hyalomma genus in particular H. anatolicum species. Targeting 18S rRNA gene, molecular examination of 148 samples of ticks by the conventional PCR assay revealed that 10.14% were positively infected with T. annulata. Distribution of PCR results reported a significant elevation (P<0.0467) in positive Theileria annulata infections in July (20.93%) but significant reduction in April (3.45%) and May (2.78%) in comparison with June (10%). In conclusion, this study demonstrated the highly prevalence of ticks in buffaloes especially with increasing of environmental temperature in summer months. Hard ticks of Hyalomma genus in particular H. anatolicum remain the most incidence ticks among buffaloes population. Molecular detection of Theileria annulata in study ticks demonstrated their roles in transmission of infection to other healthy buffaloes. Moreover studies on ticks of infested buffaloes or other field animals using the molecular assays appear of great importance to estimate its role in transmission of other pathogens.