Molecular identification and phylogenetic analysis of Trypanosoma evansi from dromedary camels (Camelus dromedarius) in Egypt, a pilot study

Animal trypanosomiasis is one of the major constraints of livestock industry in developing countries. In the present study, prevalence of Trypanosome evansi was assessed in the blood of dromedary camels (Camelus dromedarius) brought to Al Bassatein abattoir, Cairo, Egypt, by mouse inoculation test out of 84 tested camels, 4 animals (4.7%) were infected. Molecular analysis was achieved by PCR amplification and sequence analysis of part of ribosomal RNA gene including 18S, ITS1, 5.8S and ITS2 regions. Despite the conserved nature of 18S region, ITS region showed obvious heterogeneity compared to analogous sequences in database. Analysis of transferrin receptor encoding gene (ESAG6) showed variable repertoire in the studied isolates, which may indicate to a novel structure of T. evansi population from Egypt and/or a difference in host range. Furthermore, analysis of variable surface glycoprotein RoTat 1.2 gene marker revealed some heterogeneity at this gene locus. To our knowledge, this is the first molecular analysis of T. evansi in Egypt.

Graphical abstractMolecular analysis and phylogeny of Trypanosoma evansi from Egypt were done based on partial sequence of ribosomal RNA, ESAG6 and VSG RoTat 1.2 gene markers. Phylogenetic relationships (MP) of Egyptian isolates of Trypanosoma parasites with other salivarian trypanosomes based on ITS2 rRNA.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ In this manuscript the prevalence of Trypanosoma evansi was determined in the blood of naturally infected camels by mouse inculcation test. ▶ Positive samples were propagated in mice and trypanosomes were separated by anion exchange chromatography. ▶ DNA was extracted and the target gene markers were amplified by PCR technique. ▶ Obtained PCR fragments were cloned into the appropriate vectors. ▶ Cloned products were sequenced in both directions, aligned and consensus sequences were subjected to blast homology search. ▶ Phylogeny was inferred using maximum parsimony method as implemented in the MEGA 4 software based on the fragments of rRNA gene segment. ▶ Variability at ESAGE6 repertoire and VSG RoTat 1.2 was determined by aligning the obtained sequences with analogues in the database.