Molecular characterization of Trypanosoma cruzi Mexican strains and their behavior in the mouse experimental model

César Gómez-Hernández,Henrique Borges Kappel,José Alejandro Martinez-Ibarra,Karine Rezende-Oliveira,Luis Eduardo Ramírez,Gabriel Antônio Nogueira Nascentes,Eliane Lages-Silva,Francisco Trujillo Contreras,Lara Rocha Batista

doi:10.1590/s0037-86822011005000058

Abstract

For a long time, the importance of Chagas disease in Mexico, where many regarded it as an exotic malady, was questioned. Considering the great genetic diversity among isolates of Trypanosoma cruzi, the importance of this biological characterization, and the paucity of information on the clinical and biological aspects of Chagas disease in Mexico, this study aimed to identify the molecular and biological characterization of Trypanosoma cruzi isolates from different endemic areas of this country, especially of the State of Jalisco. Eight Mexican Trypanosoma cruzi strains were biologically and genetically characterized (PCR specific for Trypanosoma cruzi, multiplex-PCR, amplification of space no transcript of the genes of the mini-exon, amplification of polymorphic regions of the mini-exon, classification by amplification of intergenic regions of the spliced leader genes, RAPD (random amplified polymorphic DNA). Two profiles of parasitaemia were observed, patent (peak parasitaemia of 4.6×10(6) to 10(7) parasites/mL) and subpatent. In addition, all isolates were able to infect 100% of the animals. The isolates mainly displayed tropism for striated (cardiac and skeletal) muscle. PCR amplification of the mini-exon gene classified the eight strains as TcI. The RAPD technique revealed intraspecies variation among isolates, distinguishing strains isolated from humans and triatomines and according to geographic origin. The Mexican T. cruzi strains are myotrophic and belong to group TcI.

Highlights

For a long time, the importance of Chagas disease in Mexico, where many regarded it as an exotic malady, was questioned
Five (62.5%) strains presented patent parasitaemia as determined by the method of Brener, including three isolates from triatomines (CGH3, CGH4, and CGH6) and the two strains isolated from humans (INC-5 and NINOA)
Control programs for Chagas disease and its vector have only recently been implemented in this country, whereas such programs have been already established in South American countries for several years[3,32]

Summary

Introduction

The importance of Chagas disease in Mexico, where many regarded it as an exotic malady, was questioned. In the past, Chagas disease was considered to be restricted to the American continent where it is found in 18 countries, it has become a worldwide disease due to intense people migration This disease is a public health problem because it causes increased morbidity and mortality in South America, Central America, and Mexico, where it is considered to be a neglected disease. In the 1970s, the largest number of acute Chagas disease cases in the country was recorded in the state of Jalisco[7,8] Since this time only isolated acute cases have been diagnosed, a fact suggesting a large number of unreported sick people. The prevalence of Chagas disease in this state ranges from 1.8% to 17% in the general population and 21.6% in the rural population[6,9]

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Conclusion