Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, Tulane University, School of Public Health and Tropical Medicine, New Orleans, LA, USA.
Department of Ecology & Evolutionary Biology, Tulane University, New Orleans, LA, USA; Department of Ecology & Evolutionary Biology University of Tennessee, Knoxville, USA.
J Microbiol Immunol Infect. 2020 Aug;53(4):622-633. doi: 10.1016/j.jmii.2018.12.004. Epub 2018 Dec 21.
BACKGROUND/PURPOSE: The parasitic protozoa Trypanosoma cruzi, is widely distributed throughout the Americas. We explored the nature of T. cruzi infection in small rodents from New Orleans (LA, USA), an enzootic region of the parasite in North America.
We characterized the full complement of discrete typing units (DTUs) in rodent hosts through next-generation metabarcoding, as conventional PCR and Sanger sequencing approaches only detect the dominant genotype in biological samples. We assayed DTU diversity in tissue samples from 6 T. cruzi PCR positive rodents. The intergenic region of the mini-exon gene was amplified and sequenced on a MiSeq platform. A total of 141 sequences were aligned using Muscle, and TCS networks were constructed to identify DTUs in the samples.
We detected distinct and varying assemblages of DTUs in the rodent hosts. Highly diverse DTU assemblages were detected, with 6-32 haplotypes recovered per individual, spanning multiple DTUs (TcI,TcII, TcIV, TcV and TcVI). Haplotypes varied in frequencies from 82% to less than 0.1%. DTU composition varied according to the tissue analyzed. Rural and urban rodents carried similarly diverse DTU assemblages, though urban rodent species tended to harbor more haplotypes than their sylvatic counterparts.
Our results affirm that mammalian hosts can concurrently harbor a diverse complement of parasites, and indicate that there is greater diversity of T. cruzi DTUs present in North America than previously thought. Further investigation is warranted to understand the role of commensal rodents as a reservoir for T. cruzi in sylvatic and peridomestic environments.
背景/目的：寄生原生动物克氏锥虫广泛分布于整个美洲。我们探索了新奥尔良（美国路易斯安那州）小型啮齿动物中克氏锥虫感染的性质，新奥尔良是北美的一个寄生虫地方性流行区。
我们通过下一代代谢条形码技术，对啮齿动物宿主的离散基因型单位（DTU）进行了全面特征描述，因为传统的 PCR 和 Sanger 测序方法只能检测生物样本中的主要基因型。我们检测了 6 只 T. cruzi PCR 阳性啮齿动物组织样本中的 DTU 多样性。使用 MiSeq 平台扩增和测序小外显子基因的基因间区。使用 Muscle 对齐总共 141 个序列，并构建 TCS 网络以鉴定样品中的 DTU。
我们在啮齿动物宿主中检测到了不同且变化的 DTU 组合。检测到高度多样的 DTU 组合，每个个体回收 6-32 个单倍型，跨越多个 DTU（TcI、TcII、TcIV、TcV 和 TcVI）。单倍型的频率从 82%到低于 0.1%不等。DTU 组成根据分析的组织而变化。农村和城市啮齿动物携带相似多样的 DTU 组合，尽管城市啮齿动物的物种往往比其森林同类携带更多的单倍型。
我们的结果证实哺乳动物宿主可以同时携带多样化的寄生虫，并且表明北美的 T. cruzi DTU 多样性比以前认为的要大。需要进一步调查以了解共生啮齿动物在森林和半家环境中作为 T. cruzi 储主的作用。
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