Chagas disease, which is found widely in Latin America and has a great impact on public health, is caused by the parasite Trypanosoma cruzi. It is a neglected parasitic disease that urgently requires rapid diagnostic methods. The objective of this study was to develop a SYBR Green real-time quantitative polymerase chain reaction (qPCR) technique for the direct identification and quantification of T. cruzi from experimentally contaminated açai fruit samples. We used discrete typing units, TcI, containing 3.5 × 10⁴ cells/mL, to infect the pulp of the açai fruit. This was followed by DNA extraction using a standardized procedure. The DNA samples were quantified and amplified at specific time and temperature intervals. The specificity of the oligoinitiators used in the qPCR assays was estimated by calculating the primer dissociation curve (melting curve) along with a detection threshold using different concentrations of DNA. The method used here demonstrated good efficiency and precision for the detection and quantification of T. cruzi DNA, with a detection limit of 2.65 × 10⁻¹⁴ g/μL DNA. The qPCR technique presented here could serve as an important tool for the diagnosis of T. cruzi parasites in açai.

中文翻译：

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SYBR Green qPCR 技术用于检测巴西莓果浆中的克氏锥虫。

南美锥虫病是由寄生虫克氏锥虫引起的，在拉丁美洲广泛存在，对公众健康有很大影响。这是一种被忽视的寄生虫病，迫切需要快速诊断方法。本研究的目的是开发一种 SYBR Green 实时定量聚合酶链反应 (qPCR) 技术，用于从实验性污染的巴西莓果实样品中直接鉴定和定量T. cruzi。我们使用了离散类型单元 TcI，包含 3.5 × 10 ⁴细胞/mL，感染巴西莓果实的果肉。然后使用标准化程序进行 DNA 提取。在特定的时间和温度间隔对 DNA 样品进行定量和扩增。qPCR 检测中使用的寡引发剂的特异性通过计算引物解离曲线（熔解曲线）以及使用不同浓度 DNA 的检测阈值来估计。此处使用的方法在T. cruzi DNA的检测和定量方面表现出良好的效率和精度，检测限为 2.65 × 10 ^-14 g/μL DNA。这里介绍的 qPCR 技术可以作为诊断açai中T. cruzi寄生虫的重要工具。