trypanosoma cruzi: evaluation of pcr as a laboratory tool to follow up the evolution of parasite load

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.