Biological and biochemical characterization of isolates of Trypanosoma evansi from Pantanal of Matogrosso - Brazil

Ten isolates of Trypanosoma evansi from the Pantanal region of Brazil, rece ntly derived from coati (Nasua nasua, carnivora, Procyonidae), horses and d ogs, were characterized on the basis of biological (experimental infections in Wistar rats) and biochemical (multilocus enzyme eletrophoresis) data. B iological data were analyzed by Nested analysis of variance and Kruskal-Wal lis. Marked heterogeneity in virulence was observed in the isolates. Some o f the isolates showed an undulating parasitaemia, typical for African trypa nosomes, This biological heterogeneity did not correspond with the biochemi cal homogeneity observed in the T. evansi isolates. T. evansi has one of th e widest distributions and greatest range of mammalian hosts and is widely recognized to have evolved from Trypanosoma brucei. Adaptability of T. evan si was not reflected in the variability of biochemical and molecular parame ters studied to date. The variability in virulence was very significant, bu t not correlated with the host from which it was derived. These data sugges ted that, in the region studied, T. evansi is transmitted among both domest ic and sylvatic animals in one single transmission cycle. (C) 2000 Elsevier Science B.V. All rights reserved.