microscopic and molecular detection of theileria (babesia) equi infection in equids of kurdistan province, iran

background: equine piroplasmosis (ep) is the cause of persistent tick-borne infection with no symptoms, but the most important problem of ep is due to the persistent carrier state. carrier animals to babesia ( theileria ) equi (laveran 1901) and b. caballi (nuttall, 1910) infestation could be identified by extremely sensitive pcr-based method. the purpose of this study was to identify the causative agents of equine piroplasmosis based on molecular and microscopic assays in equids from kurdistan province, iran. methods : thirty one horse and mule blood samples were used with history of liv­ing in kurdistan province of iran.  the blood specimens were utilized for t. equi and b. caballi dna identification by pcr and giemsa stained smears for micro­scopic observation. results : the results clearly showed the presence of b. ( theileria ) equi dna in 30 of 31 blood samples (96.77%), but the microscopic examination revealed the 3 of 31 positive babesia like organisms in the red blood cells (9.67%).  conclusion : the obtained results demonstrated the presence of hidden b. ( theil­eria ) equi infection in horses with previous habitance in kurdistan province of iran. the carrier animals became a main source of infection and can transmit the disease. therefore, hidden infection might be considered as a health threatening and limit­ing factor in animals used in therapeutic antisera research and production centers.