Geographical Distribution of Trypanosoma cruzi Genotypes in Venezuela

Chagas disease is an endemic zoonosis native to the Americas and is caused by the kinetoplastid protozoan parasite Trypanosoma cruzi. The parasite is also highly genetically diverse, with six discrete typing units (DTUs) reported TcI – TcVI. These DTUs broadly correlate with several epidemiogical, ecological and pathological features of Chagas disease. In this manuscript we report the most comprehensive evaluation to date of the genetic diversity of T. cruzi in Venezuela. The dataset includes 778 samples collected and genotyped over the last twelve years from multiple hosts and vectors, including nine wild and domestic mammalian host species, and seven species of triatomine bug, as well as from human sources. Most isolates (732) can be assigned to the TcI clade (94.1%); 24 to the TcIV group (3.1%) and 22 to TcIII (2.8%). Importantly, among the 95 isolates genotyped from human disease cases, 79% belonged to TcI - a DTU common in the Americas, however, 21% belonged to TcIV- a little known genotype previously thought to be rare in humans. Furthermore, were able to assign multiple oral Chagas diseases cases to TcI in the area around the capital, Caracas. We discuss our findings in the context of T. cruzi DTU distributions elsewhere in the Americas, and evaluate the impact they have on the future of Chagas disease control in Venezuela

Trypanosoma cruzi: parasitism in adipose connective tissue

Trypanosoma cruzi, causante de la enfermedad de Chagas, es un hemoflagelado ubicuo e intracelular obligatorio de mamíferos. Macrófagos y adipocitos han sido incriminados como blancos de la invasión temprana por ese parásito; a pesar de ello, su histotropismo es estudiado habitualmente en la musculatura, órganos digestivos y estructuras nerviosas por presentar patología más frecuentemente. En este trabajo se investigó al tejido conectivo graso como un microambiente apropiado para T. cruzi en la fase aguda de la infección, inoculando vía subcutànea a ratones NMRI con aislados caracterizados por RAPD como Zimodeme 1 (Z1=T. cruzi I) obtenidos de Panstrongylus geniculatus; Rhodnius prolixus, Didelphis marsupialis; glándulas anales de estos marsupiales, Rattus rattus y humanos de zonas urbanas y rurales de Venezuela. Animales con parasitemias elevadas (10^5 tripomastigotes/mL de sangre) fueron sacrificados durante la fase aguda de la infección mediante sobreanestesia para retirarles fragmentos de tejido conectivo adiposo univacuolado anexo al esternón, que fueron trabajados histológicamente y teñidos con H-E. Parasitismo intracelular escaso a intenso (1-10/31- 40 pseudoquistes en 50 campos de 400X, respectivamente) con la presencia de estadios amastigotes o tripomastigotes fue producido en macrófagos y adipocitos de ratones. Los resultados muestran que poblaciones de T. cruzi pueden colonizar frecuentemente al conectivo adiposo, independientemente del hospedador experimental y del área geográfica del cual se aislaron; por ello, el estudio de este tejido es recomendado en investigaciones sobre la caracterización de esta parasitosis. Se discuten estos resultados en relación con el hallazgo de T. cruzi en hábitats particulares, como las glándulas anales de marsupiales ricas en lípidos, en las cuales su polimorfismo y metaciclogénesis son dependientes de niveles adecuados de material graso.210 - [email protected]@hotmail.comBimestralTrypanosoma cruzi, an ubiquitous obligatory intracellular hemoflagelate, is responsible for Chagas´s disease in mammals. Macrophages and adipocytes have been considered as to be early parasite invasion targets; even when historically their tissue behavior has usually been studied in muscles and digestive and nervous structures which are generally damaged. In this study connective adipose tissue was investigated as a adequate micro-environment for T. cruzi, during infection acute phase, by inoculating NMRI mice with isolates, which were characterized by RAPD such as Zimodeme 1 (Z1= T. cruzi I) and obtained from Panstrongylus geniculatus, Rhodnius prolixus, Didelphis marsupialis, anal glands from these marsupials, Rattus rattus and humans from urban and rural areas of Venezuela. Animals with high parasite levels (1-10/31-40 pseudocysts/50 fields 400X) were sacrificed during the high infection level phase, with the presence of amastigotes or trypomastigotes which were produced in mice macrophages and adipocytes. The results show that T. cruzi populations can usually colonize fat tissues, regardless of the host or the geographic areas in which they were isolated. The study of this tissue is recommended in research on the characterization of this parasitosis. The results are discussed in relation to the findings of T. cruzi in special habitats, such as the fat rich marsupial anal glands, since their polymorphism and metacyclogenesis are dependent on adequate levels of lipid materials

Isoenzyme profiles of GPI and PGM from representative circulating Venezuelan <i>Trypanosoma cruzi</i> strains.

<p>Loading order, left to right: TcI, WA250 cl 10B; TcII, Esmeraldo cl2; TcIV, CanIII cl 1; 1, 8839(TcIV); 2, 8196(TcIV); 3, 10141(TcI); 4, 10610(TcIV); 5, 8089(TcI); 6, 6872(TcI); 7, PGN23(TcI); 8, PGN27(TcIV); 9, PGN31(TcI).</p

Distribution of <i>Trypanosoma cruzi</i> Discrete Typing Units (DTUs) in Venezuela.

<p>The three maps display samples collected from humans (top left), vectors (top right), and mammal reservoirs (bottom left). Pie chart area is proportional to sampling size. Pie segment colour represents DTU identity. Inset on each map shows the capital (Caracas) and surrounding states in greater detail.</p

Geographical distribution of <i>Trypanosoma cruzi</i> genotypes from different hosts in Venezuela.

**<p>Morphological and molecular identification.</p>*<p>Morphological identification only.</p

RAPD profiles of representative circulating Venezuelan <i>Trypanosoma cruzi</i> strains.

<p>Loading order, left to right <b>A</b>: 1, CanIII cl 1 (TcIV); 2, Esmeraldo cl2 (TcII); 3, WA250 cl 10B (TcI); 4, 8839(TcIV); 5, 8196(TcIV); 6, 10141(TcI); 7, 10610(TcIV); 8, 8089(TcI); 9, 6872(TcI); 10, PGN23(TcI); 11, PGN27(TcIV); 12, PGN31(TcI); L, 1 kb DNA Ladder. <b>B</b>: 1, CanIII cl1 ; 2, Esmeraldo cl2; 3, WA250 cl 10B; 4, 11932; 5, 7082; 6, 8104; 7, 7570; 8, 7780; 9, SJ1097; 10, pgn2; 11, PGCHG; 12, CD45.</p