CONCLUSION

This study provides the first comprehensive molecular evidence of T. orientalis infection in cattle and their naturally infesting ticks from Wasit Province, Iraq, and the first phylogenetic characterization linking host- and vector-derived isolates in the country. Conventional PCR detected T. orientalis in 12.35% of cattle and 9.41% of tick samples. Infection was significantly associated with host age and sex, with cattle aged >3–6 years exhibiting the highest risk of infection, whereas male cattle showed a significantly higher prevalence and risk of infection than females. Phylogenetic analysis based on the 18S rRNA gene demonstrated a high degree of genetic conservation among Iraqi isolates, with cattle isolates clustering closely with a Turkish reference isolate and tick isolates showing close genetic relationships with both Turkish and Chinese isolates, indicating possible regional circulation of genetically related T. orientalis lineages.

From a practical perspective, these findings provide valuable baseline molecular epidemiological data that can support the development of evidence-based surveillance programs, risk-based tick-control strategies, and early molecular diagnosis of oriental theileriosis in Iraq. Simultaneous molecular investigation of cattle and their associated ticks also improves understanding of host-vector relationships and may facilitate more effective integrated control programs to reduce production losses from tick-borne diseases.

A major strength of this study is the combined evaluation of host- and vector-derived samples using molecular detection, DNA sequencing, and phylogenetic analysis, thereby generating the first integrated molecular dataset for T. orientalis in Iraq.

Future studies should include larger nationwide surveys involving different ecological regions, cattle breeds, and tick species while incorporating more discriminatory molecular markers, such as MPSP, ITS, mitochondrial genes, or whole-genome sequencing, to characterize circulating genotypes and clarify transmission dynamics. Longitudinal investigations integrating vector ecology, genotype distribution, and clinical outcomes will further enhance understanding of the epidemiology of T. orientalis and support sustainable control strategies for the Iraqi cattle industry. Overall, this study establishes an important molecular foundation for future surveillance and contributes to the growing body of knowledge on the epidemiology and phylogenetic diversity of T. orientalis in the Middle East.