TRYPANOSOMA-EVANSI AND T-EQUIPERDUM - DISTRIBUTION, BIOLOGY, TREATMENT AND PHYLOGENETIC RELATIONSHIP (A REVIEW)

Trypanosoma evansi and T. equiperdum were compared regarding their ult rastructure, their mammalian hosts, way of transmission, pathogenicity , diagnosis and treatment, and biochemical and molecular characteristi cs. Electron microscopic investigation revealed no ultrastructural dif ferences between the two species except that there were more coated ve sicles in the flagellar pocket of T. equiperdum. Biological, biochemic al and molecular studies were reviewed and exhibited many similarities between T. evansi and T. equiperdum. The most prominent differences b etween the two species are the presence of maxicircles in T. equiperdu m, which are missing in T. evansi, and the route of transmission. Whil e T. evansi is transmitted by biting flies, T. equiperdum is transmitt ed from one equine host to another during copulation when mucous membr anes come into contact. Otherwise the two species are remarkably simil ar. The phylogenetic relationship between the two species and T. b. br ucei is being discussed, and the hypothesis is proposed that T. evansi arose from a clone of T. equiperdum which lost its maxicircles. (C) 1 998 Elsevier Science B.V. All rights reserved.