León Cielo M, Hernández Carolina, Montilla Marleny, Ramírez Juan David
Red Chagas Colombia, Instituto Nacional de Salud, Bogotá, Colombia.
Grupo de Parasitología, Instituto Nacional de Salud, Bogotá, Colombia.
Mem Inst Oswaldo Cruz. 2015 May;110(3):387-93. doi: 10.1590/0074-02760140402. Epub 2015 Apr 28.
Trypanosoma cruzi is the aetiological agent of Chagas disease, which affects approximately eight million people in the Americas. This parasite exhibits genetic variability, with at least six discrete typing units broadly distributed in the American continent. T. cruzi I (TcI) shows remarkable genetic diversity; a genotype linked to human infections and a domestic cycle of transmission have recently been identified, hence, this strain was named TcIDom. The aim of this work was to describe the spatiotemporal distribution of TcI subpopulations across humans, insect vectors and mammalian reservoirs in Colombia by means of molecular typing targeting the spliced leader intergenic region of mini-exon gene. We analysed 101 TcI isolates and observed a distribution of sylvatic TcI in 70% and TcIDom in 30%. In humans, the ratio was sylvatic TcI in 60% and TcIDom in 40%. In mammal reservoirs, the distribution corresponded to sylvatic TcI in 96% and TcIDom in 4%. Among insect vectors, sylvatic TcI was observed in 48% and TcIDom in 52%. In conclusion, the circulation of TcIDom is emerging in Colombia and this genotype is still adapting to the domestic cycle of transmission. The epidemiological and clinical implications of these findings are discussed herein.
克氏锥虫是恰加斯病的病原体，该病影响了美洲约800万人。这种寄生虫表现出遗传变异性，在美洲大陆广泛分布着至少六个离散型单元。克氏锥虫I型（TcI）显示出显著的遗传多样性；最近已鉴定出一种与人类感染和家庭传播周期相关的基因型，因此，该菌株被命名为TcIDom。本研究的目的是通过针对小外显子基因剪接前导基因间区域的分子分型，描述哥伦比亚人类、昆虫媒介和哺乳动物宿主中TcI亚群的时空分布。我们分析了101株TcI分离株，观察到野生型TcI的分布占70%，TcIDom占30%。在人类中，该比例为野生型TcI占60%，TcIDom占40%。在哺乳动物宿主中，分布情况为野生型TcI占96%，TcIDom占4%。在昆虫媒介中，观察到野生型TcI占48%，TcIDom占52%。总之，TcIDom的传播在哥伦比亚正在出现，并且这种基因型仍在适应家庭传播周期。本文讨论了这些发现的流行病学和临床意义。
