RESUMEN
Twenty-three blood samples were used in this study; five were from five naturally infected horses with Babesia equi [B. equi], while eighteen were from asymptomatic horses with equine babesiasis from different localities in Egypt. All samples were subjected to microscopic examination, indirect fluorescent antibody test [IFA] and polymerase chain reaction [PCR]. The carrier animals were microscopically detected in 7 out of 18 samples [38.8%] and in 9 of 18 by using IFA [50%], whereas PCR revealed that 14 samples were positive [78%]. Two synthetic oligonucleotide primers, based on the B. equi merozoite antigen gene [EMA-1] were used. A 819 bps DMA fragment is specifically amplified from the gene encoding EMA-1 of B. equi. Our results demonstrate that PCR is a valuable technique for routine detection of B. equi in chronically infected horses, even at low parasitaemia levels