Theileriosis, caused by tick-borne hematozoan organisms, is a protozoan disease of domestic and wild mammals. The most phylo-molecular explorations of genus Theileria have been globally focused on the livestock and here are few investigations about canine Theileriosis. Twenty three and 52 blood samples were collected from sheepdogs and their owners, respectively, at different geographical foci of Mazandaran province (East, Central, and West regions), Northern Iran. To primary identify, the taken blood samples were fixed, stained, and surveyed by microscopic observation. DNA samples were extracted and amplified by polymerase chain reaction of 18s rRNA gene. The amplicons were directly sequenced to explore Theileria spp., and their heterogeneity traits. Sequencing and phylogenetic analyses revealed definitely the presence of Theileria luwenshuni, Theileria ovis, and Theileria buffeli (13 %) in sheepdog isolates, while no infection was found in dog owners. Consensus positions of T. luwenshuni showed two amino acid substitutions (haplotype diversity; 0.9) in codons 53 and 64 compared to wild type with identity 99.5 % and divergence 0.5-1.1, also one codon substitution (Hd; 0.875) found in T. buffeli with identity 97.6-99.5 % and divergence 0.5-2.5. No novel haplotype was identified in T. ovis isolate. The current results strengthen our understanding about genetic variability, molecular taxonomic status, and epidemiology of canine theileriosis among sheepdogs and their owners in Iran where there is no similar study. As well, it will facilitate the implementation of measures to control theileriosis in the region. Based on our knowledge, the current study presents the first report of T. luwenshuni, T. buffeli, and T. ovis infections in sheepdogs worldwide.
Keywords: Dog owners; Northern Iran; Sheepdogs; T. buffeli; T. luwenshuni; T. ovis.