Identification and genetic diversity of ticks in local sheep in Samarra city, Northern of Baghdad, Iraq.

Abstract

This study reported hard tick (Ixodida: Ixodidae) infestation in sheep of Samara city, north of Baghdad, from June to December 2023. A total of 480 ticks were manually pulled out from the sheep with an ethanol-soaked tissue and preserved in plastic containers containing 70% ethyl alcohol. All samples were counted and examined individually under a light microscope to identify the genus. Preliminary microscopic examination revealed that the majority of the collected ticks were Hyalomma, with 91.4%, followed by Rhipicephalus (6.8%) and Ixodes (1.8%). Furthermore, Hyalomma was dominant across all months, with a peak relative abundance in October (100%). The peak relative abundances for Rhipicephalus (16%) and Ixodes (4.3%) occurred in July. Under further microscopic evaluation, morphological features demonstrated three species, namely, Hyalomma detritum (Koch), Hy. anatolicum (Koch) and Rhipicephalus sanguineus sensu lato (Latreille). To confirm genera and species, molecular diagnosis was performed, based on the COX1 gene, resulting in the identification of five species, namely, Hy. detritum, Hy. anatolicum, Hy. excavatum (Koch, 1844), Rh. sanguineus sensu lato and an unidentified Ixodes sp. While the Ixodes scapularis isolation unexpectedly revealed genetic resemblance to North American samples, indicating a wider geographical spread, the Hyalomma and Rhipicephalus isolates shared ancestry with other Middle Eastern strains, demonstrating regional genetic stability. These results showed the comprehensive diversity of tick species in sheep, including Hyalomma, Rhipicephalus and Ixodes, and also provided good epidemiological data to support the preventative procedures of tick-borne infections in Samarra city.