Abstract. Thirty-six Trypanosomatidae stocks isolated from various hosts and geographical areas in Colombia and 7 others from Bolivia, Chile, Honduras and Panama have been surveyed by Multilocus Enzyme Electrophoresis (MLEE). Part of the Colombian stocks were previously characterized by morphology and biological behavior as belonging to Trypanosoma cruzi and Trypanosoma rangeli taxa, others were unknown species. The genetic variability observed at 13 different loci was considerable, since 38 zymodemes could be distinguished and 2 upper branches were observed. The first branch corresponded to T. cruzi and was divided in the two major phylogenetic subdivision of T. cruzi (T. cruzi I, T. cruzi II). The majority of the Colombian T. cruzi stocks (92%) felt into T. cruzi I. Only two stocks, isolated from sylvatic mammals, belonged to T. cruzi II. Among T. cruzi I, we did not observed any additional phylogenetic subdivision and host-dependent genotype specificity. The second branch was genetically very heterogeneous and included all T. rangeli stocks, the stocks isolated from bats and one stock isolated from a sylvatic R. prolixus vector. The stocks belonging to T. rangeli presented only one locus instead of two for the malic enzyme system. Since, the upper level of resolution of the isoenzyme method was exceeded, the current clustering study failed to draw a clear distinction between such a diverse set of Trypanosomatidae species.
During a study of intestinal parasitic infections in human immunodeficiency virus-positive patients, a parasite belonging to the phylum Myxozoa, recently described from human samples, was identified in one sample. When this parasite was stained by the modified Ziehl-Neelsen staining method, the features of the spores were identified: they were pyriform in shape, had thick walls, and had one suture and two polar capsules, with each one having four or five coils. The suture and two polar capsules were observed with the chromotrope-modified stain. The number of stools passed was more than 30 per day, but oocysts of Isospora belli were also found. Upon reexamination of some formalin-or merthiolate-iodine-formaldehyde-preserved samples an identical parasite was found in another sample from a patient presenting with diarrhea. Strongyloides stercoralis larvae and eggs of Hymenolepis nana and Ascaris lumbricoides were also found in this sample. Given that both patients were also infected with other pathogens that cause diarrhea, the possible pathogenic role of this parasite could not be established. The probable route of infection also could not be established.
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