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

Abstract

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.

Prevalence of Trypanosoma evansi in livestock in Palestine

“…In this study, a phylogenetic and molecular analysis of the 18S rRNA sequences has shown that one genotype of T. evansi was present in camels from Palestine. However, for more accurate phylogenetic analyses, it is important to sequence additional non-coding DNA regions from T. evansi that are genetically diverse such as the internal transcribed spacer (ITS) region [50]. A study conducted by Pourjafar et al [50] showed that a phylogenetic analysis based on ITS2 nucleotide sequences revealed heterogeneity among the tested T. evansi parasites.…”

Trypanosoma evansiand Surra: A Review and Perspectives on Origin, History, Distribution, Taxonomy, Morphology, Hosts, and Pathogenic Effects

“…Indeed, when leaving the tsetse belt “jail” in which it was trapped by its cyclical development in tsetse flies, T. evansi developed, or simply expressed, a surprising and spectacular ability to develop in a very large range of hosts leading to a no less spectacular, potentially unlimited, geographical distribution. Although T. evansi has long been claimed to be a genetically and morphologically highly homogeneous parasite [205], recent investigations have demonstrated more diversity than expected [206]. Moreover, it is obvious, when comparing T. evansi to T. brucei , that some slight modifications in the nucleotidic sequence of a genome have deeply impacted the biological properties of a parasite, affording it very different characteristics and behaviours, both in terms of host range, pathogenicity, transmission, epidemiology, and geographical distribution.…”

Molecular prevalence and phylogenetic analysis of Theileria annulata and Trypanosoma evansi in cattle in Northern Tunisia

“…In this context, the introduction of infected animals is a risk factor for spread of the disease. Furthermore, Pourjafar et al (2013) showed that T. evansi probably related to the capacity for rapid adaptation to different host species and environments. We recommend undertaking additional studies to further understand the importance of co-infection between the two pathogens.…”