The prevalence of Babesia and Theileria species in sheep and vector ticks in Tonkabon and Ramsar areas of Iran was investigated. A total of fifty blood samples and 45 ticks were collected from sheep from local flocks, suspected of piroplasmosis during 2013-2014. Giemsa stained blood smears were screened for piroplasms. DNA extracted from blood samples and salivary glands and ovaries of ticks were amplified with primers for Babesia spp. and Theileria spp. by semi nested-PCR. Piroplasms were observed in 22 (44%) blood smears. In the first round of semi-nested PCR, the frequency of Theileria spp. and Babesia spp. in the sheep were 37 (74%) and 7 (14%), respectively. The results of semi-nested PCR showed that the frequency of T. ovis, T. lestoquardi, mixed Theileria infection, B. ovis and B. motasi were 16 (32%), 17 (34%), 17 (34%), 6(12%) and 1(2%), respectively. Out of the 45 ticks collected, 39 were identified as Rhipicephalus bursa (86.7%), three were Dermacentor raskimensis (6.7%), two were Hyalomma marginatum (4.4%) and one was Haemaphysalis spp. (2.2%).Piroplasms could not be detected in salivary glands and ovary samples of ticks by semi-nested PCR. Based on the results of the study, it was concluded that piroplasm infection is common in sheep in Ramsar and Tonkabon areas.

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