Molecular and phylogenetic analysis of equine piroplasms in the Republic of Korea

This study was conducted to screen out horses infected with piroplasms using PCR and to assess the phylogenetic variations of the piroplasm isolates. From 2007 to 2010, a total of 224 blood samples of horses were collected from three provinces of Korea and analyzed by PCR using primers specific to the 18S rRNA of piroplasms. Out of 224 samples analyzed, only two (0.9%) horses were found positive for Theileria equi. Sequencing of the complete 18S rRNA of T. equi from the two horses (GG-7 and GG-14) whose information was submitted to the GenBank (accession nos. HM229407 and HM229408, respectively) showed 100% identity. Alignment of the complete sequences of T. equi 18S rRNA with the GenBank databases of T. equi showed a high degree of homology (98.6-99.8%). The phylogenetic analysis showed T. equi GG-7 and GG-14 clustered together with T. equi isolates from Spain, Sudan, Jordan and South Africa, indicating the possibility of a close epidemiological link among these isolates.