Trypanosoma cruzi strain TcI is associated with chronic Chagas disease in the Brazilian Amazon.

Rosa Amélia Gonçalves Santana,George Allan Villarouco Da Silva,Henrique Silveira,Jorge Augusto Oliveira Guerra,João Marcos Barbosa-Ferreira,Marcel Gonçalves Maciel,Laylah Kelre Costa Magalhães,Suzane Ribeiro Prestes,Felipe Rocha De Brito,Maria Das Graças Vale Barbosa,Laise Kelman Costa Magalhães,Wuelton Marcelo Monteiro,Leila Inês De Aguiar Raposo Câmara Coelho

doi:10.1186/1756-3305-7-267

Abstract

BackgroundChagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. Chronic disease cases have been detected through serological surveys. However, the mode of transmission could not be determined, or any association of chronic disease with a specific T. cruzi DTU’s. The aim of this study was to characterize Trypanosoma cruzi in patients with chronic Chagas disease in the State of Amazonas, Brazil.MethodsBlood culture and xenodiagnosis were performed in 36 patients with positive serology for Chagas disease who participated in a serological survey performed in urban and rural areas of Manaus, Amazonas. DNA samples were extracted from the feces of triatomines used for xenodiagnosis, and the nontranscribed spacer of the mini-exon gene and the mitochondrial gene cytochrome oxidase subunit II (COII) were amplified by PCR and sequenced.ResultsBlood culture and xenodiagnosis were negative in 100% of samples; however, molecular techniques revealed that in 13 out of 36 (36%) fecal samples from xenodiagnosis, T. cruzi was characterized as the DTU TcI, and different haplotypes were identified within the same DTU.ConclusionThe DTU TcI, which is mainly associated with acute cases of Chagas disease in the Amazon region, is also responsible for chronic infection in patients from a region in the State of Amazonas.

Highlights

Chagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV
Blood culture and xenodiagnosis There was no growth of T. cruzi in blood cultures, which may be a consequence of standard protocol used in the laboratory that uses a low amount of patient’s blood to start hemocultures, while other protocols use higher amounts of patient’s blood [20]
DNA amplification of the mini-exon gene T. cruzi positivity was observed in PCR of the mini-exon gene of triatomine samples after 180 days of xenodiagnosis of three (8.3%) patients, with the profile of amplified products compatible with TcI (Table 2)

Summary

Introduction

Chagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. The etiologic agent of CD is the flagellate protozoan T. cruzi, which is primarily transmitted through the feces of infected triatomines, may be transmitted by blood transfusion, transplacental route, organ transplantation, laboratory accidents and orally through contaminated food [8] This parasite presents high genetic variability and is divided in 6 specific discrete typing units (DTUs), termed TcI to TcVI [9,10]. Understanding the genetics and diversity of the parasite will provide information about its evolution, biological behavior, and epidemiological patterns; the natural history of infection; and issues related to the diagnosis and treatment of the disease [10,11]

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