Theileria and Babesia species are blood parasites that commonly cause illness in both juvenile and mature animals. The primary objective of this study was to identify the specific genotypes of Theileria and Babesia species responsible for infections in cattle and sheep. Blood samples were collected from male and female cattle and sheep slaughtered at the Al-Najaf slaughterhouse. Identification of Theileria and Babesia spp. was conducted using conventional PCR, sequencing, and phylogenetic techniques based on the 18S rRNA gene. The blood isolates from cattle and sheep were subjected to PCR-based molecular assays, which detected Theileria and Babesia infections at 694 bp and 383 bp, respectively. PCR products from positive isolates were then used for DNA sequencing to construct the phylogenetic tree of Theileria and Babesia species using partial 18S rRNA gene sequences. NCBI-Blast analysis revealed that the Theileria and Babesia species in the sheep isolates (No. 1 and No. 3) were closely related to Theileria ovis (AY508461.1) based on sequence similarity. Additionally, the sheep isolate of Theileria spp. (No. 2) was identified as Theileria lestoquardi (KP342263.1). The analysis of bovine isolates showed that the Theileria spp. isolates (No. 1 and No. 2) were highly similar to Theileria annulata (MF287951.1). Further examination of sheep isolates confirmed that the Babesia spp. isolates (No. 1 and No. 2) corresponded to Babesia ovis (MG569902.1). The genetic sequence analysis of cattle Babesia isolates (No. 1 and No. 2) revealed a 100% match with Babesia bovis (HQ264126.1). In conclusion, this study identifies Theileria ovis, Theileria lestoquardi, and Babesia ovis as the primary infecting species in sheep, while Theileria annulata and Babesia bovis primarily infect cattle. However, Theileria and Babesia species exhibit significant genetic similarities within their respective genera, suggesting the need for alternative identification techniques to accurately determine the specific species of these parasites.
Keywords | Genotype , Theileria, Babesia, PCR, DNA sequencing, 18S rRNA