Genetic characterization and phylogenetic analysis of Trypanosoma evansi in Iranian dromedary camels.

Whole blood samples were collected from 117 male clinically healthy Camelus dromedarius aged between 6 months to 18 years from several farms in Yazd Province of Iran. Trypanosoma evansi-affected camels were detected by Giemsa-stained blood smears, and the positive blood samples (4 out of 117) were submitted to PCR examination and phylogenetic analysis. Basic Local Alignment Search Tool data of the obtained complete internal transcribed spacer (ITS) sequences revealed that they corresponded to those of T. evansi, Thailand cattle isolate (AY912276) with the homology of 99 %. Both phylogenetic trees generated by ITS1 and complete ITS were unable to clearly show inter- and intraspecific genetic diversity of Trypanosoma spp. isolates. The phylogenetic tree inferred from the ITS2 nucleotide sequences (569 bp) clearly showed the genetic diversity of the parasites. Phylogenetic and molecular analyses of this region showed that two distinct genotypes of T. evansi in Iranian dromedary camels are present. In contrast to the ITS1 and ITS2 regions, multiple alignment of the nucleotide sequence of the 5.8S rRNA showed a high degree of sequence conservation during evolution in various Trypanosoma spp.