Iranian Journal of Parasitology 2016. 11(3):389-395.

Trypanosoma cruzi: Evaluation of PCR as a Laboratory Tool to Follow up the Evolution of Parasite Load
Fabiana Nabarro FERRAZ, Denise Lessa ALEIXO, Ana Paula GRUENDLING, Mônica Lúcia GOMES, Max Jean de Ornelas TOLEDO, Silvana Marques DE ARAÚJO


Background: The study evaluated qualitative PCR, primers 121-122 as a tool to follow up evolution parasite load of Trypanosoma cruzi.

Methods: The study was conducted at the State University of Maringa, in 2015. Step 1, dilutions 1/10 were performed from T. cruzi-Y strain to obtain preparations of 50,000-0.05 parasites/mL from which DNA were extracted, quantified, and amplified. Step 2, the extracted DNA in the dilutions 5-0.05 parasites/mL was re-diluted 1/10, 1/100, 1/1000, quantified, and amplified. Polyacrylamide gels were photographed and thicknesses of the 330 bp kDNA fragments were measured.

Results: Step 1, in the dilutions 50,000-50 parasites/mL kDNA fragments had same thickness and, dilutions 5-0.05 parasites/mL showed progressive decrease in thicknesses and staining intensity of the 330 bp fragments. Step 2, demonstrated that dilutions of five (re-dilutions 1/10 and 1/100) and 0.5 (1/10) parasites/mL produced similar thicknesses of the 330 bp fragments obtained in Step 1. However, very dilute DNA samples make difficult to reproduce the fragments thicknesses.

Conclusion: PCR, despite its limitations, was able to detect progressive decrease in thicknesses/staining intensity of kDNA fragments in the dilutions 5-0.05 parasites/mL. Hence, has the potential to be used to follow-up evolution of parasite load, not by quantifying the number of parasites, but by dynamic evolution of the fragments thicknesses during etiological treatment.


Trypanosoma cruzi; Parasite load; PCR; kDNA fragments

Full Text:



World Health Organization (WHO). Chagas disease (American trypanosomiasis). World Health Organization. Geneva. 2015. Access: 1 Mar 2016.

Marin-Neto JA, Rassi Jr. A, Avezum Jr. A, Mattos AC, Rassi A. The BENEFIT trial: testing the hypothesis that trypanocidal therapy is beneficial for patients with chronic Chagas heart disease. Mem Inst Oswaldo Cruz. 2009; 104 (Suppl I): 319–24.

Urbina JA. Specific treatment of Chagas disease: status and new developments. Curr Opin. Infect Dis. 2001; 14: 733–41.

Duffy T, Bisio M, Altcheh J, Burgos JM, Diez M, Levin MJ, Favaloro RR, Freilij H, Schijman AG. Accurate real-time PCR strategy for monitoring blood stream parasite loads in Chagas disease patients. PLoS Negl Trop Dis. 2009; 3: e419.

Duffy T, Cura CI, Ramirez JC etc. Analytical performance of a multiplex Real-Time PCR assay using TaqMan probes for quantification of Trypanosoma cruzi satellite DNA in blood samples. PLoS Negl Trop Dis. 2013; 7: e2000.

Moreira OC, Ramírez JD, Velázquez E, Melo MF, Lima-Ferreira C, Guhl F, Sosa-Estani S, Marin-Neto JA, Morillo CA, Britto C. Towards the establishment of a consensus real-time qPCR to monitor Trypanosoma cruzi parasitemia in patients with chronic Chagas disease cardiomyopathy: a substudy from the BENEFIT trial. Acta Trop. 2013; 125: 23-31.

Organização Pan Americana de Saúde (OPAS), 2008. Curso de Capacitação dos microscopistas de Malária e dos laboratoristas da rede pública na detecção do Trypanosoma cruzi. Modulo I. Access: 1 May 2015.

Kinoshita-Yanaga AT, Toledo MJO, Araújo SM, Vier BP, Gomes ML. Accidental infection by Trypanosoma cruzi follow-up by the polymerase chain reaction: case report. Rev Inst Med Trop S Paulo. 2009; 51: 295-8.

Pereira da Silva LH, Nussenweig V. Sobre uma cepa de Trypanosoma cruzi altamente virulenta para camundongo branco. Folia Clin e Biol. 1953; 20: 191-207.

Abolis NG, Araújo SM, Toledo MJ, Fernandez MA, Gomes ML. Trypanosoma cruzi I-III in southern Brazil causing individual and mixed infections in humans, sylvatic reservoirs and triatomines. Acta Trop. 2011; 120: 167-72.

Carranza JC, Valadares HM, D’Avila DA, Baptista RP, Moreno M, Galvão LM, Chiari E, Sturm NR, Gontijo ED, Macedo AM, Zingales B. Trypanosoma cruzi maxicircle heterogeneity in Chagas disease patients from Brazil. Int J Parasitol. 2009; 39: 963–73.

Miles MA, Feliciangeli MD, De Arias AR. American trypanosomiasis (Chagas’ disease) and the role of molecular epidemiology in guiding control strategies. BMJ. 2003; 326: 1444-8.

Brener Z. Therapeutic activity and criterion of cure on mice experimentally infected with Trypanosoma cruzi. Rev Inst Med Trop São Paulo. 1962; 4: 389-96.

Britto C, Cardoso MA, Wincker P, Morel CM. A simple protocol for the physical cleavage of Trypanosoma cruzi kinetoplast DNA present in blood samples and its use in polymerase chain reaction (PCR)-based diagnosis of chronic Chagas disease. Mem Inst Oswaldo Cruz. 1993; 88: 171–2.

Wincker P, Britto C, Pereira JB, Cardoso MA, Oelemann W, Morel CM. Use of a simplified polymerase chain reaction procedure to detect Trypanosoma cruzi in blood samples patients in a rural endemic area. Am J Trop Med Hyg. 1994; 51: 771-7.

Gomes ML, Macedo AM, Vago R, Pena SDJ, Galvão LMC, Chiari E. Trypanosoma cruzi: optimization of polymerase chain reaction for detection in human blood. Exp Parasitol. 1998; 88: 28-33.

Santos FR, Pena SDJ, Epplen JT. Genetic and population study of a Y-linked tetranucleotide repeat DNA olymorphism with a simple non-isotopic technique. Hum Genet. 1993; 90: 655-6.


  • There are currently no refbacks.

Creative Commons Attribution-NonCommercial 3.0

This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License which allows users to read, copy, distribute and make derivative works for non-commercial purposes from the material, as long as the author of the original work is cited properly.