This study aimed to detect Anaplasma phagocytophilum in horses through hematological and molecular tests. The 16S rRNA gene of the Anaplasma phagocytophilum parasite was amplified by polymerase chain reaction (PCR), then sequenced, and subjected to phylogenetic analysis to explore "Equine Granulocytic Anaplasmosis" (EGA) infection in three important gathering race horses areas in Baghdad governorate, Iraq. Blood samples were obtained from 160 horses of varying ages, three breeds, and both sexes, between January and December 2021. Prevalence and risk variables for anaplasmosis were analyzed using statistical odds ratio and chi-square tests. Results demonstrated that clinical anaplasmosis symptoms comprised jaundice, weight loss, paleness of mucus membrane with petechial hemorrhage in the third elides, and edema in extremities; There was no tick infestation. The hematological test did not significantly reveal decreases in red and white blood cells and platelet count. Microscopically found 11 from 160 smears (6.88%) had morulae within granulocytes, PCR results of Anaplasma spp primers was 32 positive amplicons (20%), and molecular sequencing results of “16S ribosomal RNA genes” confirmed 21 horses (13.13%) infected by Anaplasma phagocytophilum for the first time in Iraq horses. The results of the phylogenetic analysis revealed compatibility values similarity 98.81-99.76% with worldwide isolates. Mares occurred not significantly riskier; also age and breed were not illustrated risks of any group. This study is the first molecular detection of Anaplasma phagocytophilum in racehorses reared in Baghdad in Iraq. The outcomes of this study provide genetic data for early identification of Anaplasma phagocytophilum infection, treatment, and management of the illness in Iraq horses, as well as monitoring its transmission to the human population.
