Figure 1
Amplification and melting curves of real time PCR (qPCR) of faecal samples (FS) of Triatoma infestans fed by xenodiagnosis (XD) on patients with chronic Chagas disease, using human blood DNA negative for T. cruzi DNA as an exogenous internal control (EIC) by chromosome 12 (X12) detection. 1-A: An average Tm of 84.24°C is observed in the melting curve of every 5-fold dilution of human blood DNA negative for T. cruzi (EIC). Average Ct value 29.89. X12-qPCR reaction: efficiency = 94.4%, R2 = 0.994 and slope = -3.463. 1-B: Amplification curve for X12 of 3, 6, 12, 50 and 100 ng of EIC added to FS-XD. The Ct value for 50 ng was 29.96. No Ct value was observed in the FS-XD without EIC. 1-C: Amplification curve for X12 in purified DNA of 18 FS obtained from XD applied in patients with chronic Chagas disease incubated for 30, 60 and 90 days without EIC, showing absence of human DNA target in the evaluated samples. 1-D: An average Tm of 84.31°C is observed in the melting curve of 18 FS obtained from XD applied in patients with chronic Chagas disease incubated for 30, 60 and 90 with EIC, indicating that the generated qPCR amplicon matches the Tm value shown in 1-A.