RESUMEN
BACKGROUND: Thileriosis is a tick -born disease caused by hemoprotozoan parasites which has global veterinary and economic implications. METHODS: Blood samples were collected from 216 sheep and 83 goats from Jeddah, Saudi Arabia, were analyzed to determine whether the animals were infected with Theileria spp. parasites. The parasites were detected using a polymerase chain reaction (PCR) targeting the gene of 18S rRNA followed by sequencing. RESULTS: According to obtained findings, Theileria spp. were detected in sheep (57.8%, 48/83) and goats (51.9%, 112/216). Phylogenetic analysis to sequence data showed that T. ovis identified in this study were found to be closely connected to an isolate from Turkey, with 84.4-99.8% pairwise identity and 52.35-99.79% coverage.