RESUMEN
Objective To analyze the relationship between genetic variability and evolution among Trypanosoma brucei (including T. b. brucei, T. b. rhodesiense and T. b. gambiense), T. evansi and T. equiperdum isolates. Methods Genomic DNAs of 26 trypanosome isolates were amplified by a mobile genetic elements (MGE)-PCR technique and cluster analysis was performed based on the molecular profiles with Neighbor-Joining method. Results The genetic variability among trypanosome isolates examined was obvious with an average genetic distance of 41.2% (ranged from 0 to 100%). Similarity coefficient among T. brucei isolates was 41.15% which was lower than that between T. evansi and T. equiperdum isolates. The closest relationship was found between T. evansi and T. brucei isolates with a similarity coefficient of 62.94%. The genetic variability between T. b. rhodesiense and T. b. brucei isolates was higher than that among T. b. gambiense isolates. Conclusion Species and subspecies in Trypanozoon displayed a higher genetic variability; T. equiperdum isolates collected from China and from South America, and T. evansi isolates from China and from South America, should have a similar origin.
RESUMEN
Human African trypanosomiasis is caused by the infection of Trypanosoma brucei gambiense or T.b. rhodesiense, while another morphologically identical subspecies, T.b.brucei, and other closely related species, T.equiper-dum and T.evansi, are considered not infectious to human. This is highly related to the trypanosome lytic factor (TLF) found in normal human serum (NHS) and the serum resistance-associated (SRA) protein of trypanosomes infectious to human. We reviewed the research progress in TLF and its role in trypanosome lysis as well as the mechanism of SRA against the TLF.