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

Magnetic properties for the Mn2GeTe4 compound

Measurements of magnetic susceptibility χ, in the temperature range from 2 to 300 K, and of magnetization M vs. applied magnetic field B, up to 5 T, at various temperatures were made on polycrystalline samples of the Mn2GeTe4 compound. It was found that Mn2GeTe4 has a Néel temperature TN of about 135 K, shows mainly antiferromagnetic behavior with a very weak superimposed ferromagnetic component that is attributed to spin canting. Also, the magnetic results suggest that a possible spin-glass transition takes place at Tf≈45 K. The spin-glass order parameter q(T), determined from the susceptibility data, was found to be in agreement with the prediction of conventional spin-glass theory. The M vs. B results indicated that bound magnetic polarons (BMPs) occur in the compound, and that the effects from BMPs disappear at approximately 80 K. The M vs. B curves were well fitted by a Langevin type of equation, and the variation of the fitting parameters determined as a function of temperature. Using a simple spherical model, the radius of the BMP in the material was found to be about 27 Å; this value is similar to the effective Bohr radius for an acceptor in the II-IV-V2 and I-III-VI2 ternary semiconductor compounds. © 2008 Elsevier B.V. All rights reserved.Fil: Quintero, M.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Quintero, E.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Caldera, D.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Moreno, E.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Morocoima, M.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Grima, P.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Ferrer, D.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Marchan, N.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Bocaranda, P.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Delgado, G. E.. Universidad de Los Andes Facultad de Ciencias; VenezuelaFil: Henao, J. A.. Facultad de Ciencias; ColombiaFil: Macías, M. A.. Facultad de Ciencias; ColombiaFil: Pinto, J. L.. Facultad de Ciencias; ColombiaFil: Ponce Altamirano, Claudio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentin

Reference strains used in this study.

<p>Reference strains used in this study.</p

Oligonucleotide primers employed in this study.

<p>Oligonucleotide primers employed in this study.</p

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

<i>Trypanosoma cruzi</i> genotypes from different host species in Venezuela.

<p><i>Trypanosoma cruzi</i> genotypes from different host species in Venezuela.</p