Parasite burden was determined by quantitative real-time PCR
(qPCR). DNA was purified from cardiac biopsies with QIAamp DNA
Mini Kit following the manufacturer’s instructions. A standard
curve was generated using dog DNA spiked with serial dilutions
of T. cruzi DNA. PCR reactions contained 100 ng of dog DNA, 0.5 m
of primers TCZ-F 5-GCTCTTGCCCACAMGGGTGC-3 and TCZ-R 5-
CCAA- GCAGCGGATAGTTCAGG-3, and 10 L of EXPRESS SYBR
GreenERTM qPCR Supermix (Invitrogene) in a final volume of 20 L.
Reactions were run in triplicate on an EcoTM Real-Time PCR System
(Illumina, USA) as follows: 50 ◦C for 2 min and 40 cycles of 95 ◦C for
10 s, 55 ◦C for 15 s 72 ◦C for 5 s. High-resolution melting curves were
determined at the end of the amplification. The standard curve had
a slope of
−3.221, R2 = 0.9989 and an efficiency of 104.35%.