Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 0 0 2026 09 09 1955 1955 Farnaz Abdali-Dehdezi Department of Internal Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Shahram Jamshidi Department of Internal Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Amir Rostami Department of Internal Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Parviz Shayan Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Hesameddin Akbarein Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Iradj Ashrafi Tamai Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Nima Neyestani Department of Internal Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Kamyar Madani Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Ahoora Sheikhi Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Niloorfar Zarifian Department of Internal Medicine, Faculty of Veterinary Medicine, University of Tehran 2026 05 31 2026 08 11 Background: Canine tick-borne diseases from Ehrlichia and Anaplasma pose rising veterinary and zoonotic risks. In Iran, data on their prevalence in dogs and ticks are scarce. This cross-sectional study examined molecular rates, phylo­genetic traits, and blood disorders in high-exposure dogs, aiming to clarify infection patterns and health consequences in this understudied region. Methods: Blood samples and ticks were collected from 138 dogs in Tehran City, divided into 3 groups (tick-infested indoors, tick-infested outdoors and thrombocytopenics without ticks) and used for hematological/biochemical profiling, molecular detection and phylogenetic analysis targeting the 16S rRNA gene. Results: The study found molecular prevalence of Ehrlichia canis and Anaplasma platys at 21.7% and 11.6%, with out­door dogs highest; indoor dogs had no A. platys. Infection rates peaked in 1–3-year-old dogs. Rhipicephalus sanguineus was the sole tick collected. Thrombocytopenia signaled TBD exposure, prompting molecular screening. Phylogenetic 16S rRNA analysis confirmed genus identity and placed samples within global clusters, yet revealed no region-specific lineages due to gene conservation. Ehrlichiosis showed lower hematocrit, hemoglobin, neutrophils, and monocytes, with higher leukocytes and lymphocytes versus anaplasmosis; thrombocytopenia was prominent in both. Elevated Alanine transaminase, Aspartate Aminotransferase and globulin, and reduced albumin, were more prominent in Ehrlichiosis. Conclusion: These findings confirm active circulation of E. canis and A. platys in Tehran's canine population, with out­door exposure as a key risk factor, and demonstrate that E. canis induces more pronounced clinicopathological abnor­malities than A. platys. https://jad.tums.ac.ir/index.php/jad/article/view/1955 https://jad.tums.ac.ir/index.php/jad/article/download/1955/741