Burgos Juan M, Altcheh Jaime, Bisio Margarita, Duffy Tomas, Valadares Helder M S, Seidenstein María Elena, Piccinali Romina, Freitas Jorge M, Levin Mariano J, Macchi Liliana, Macedo Andrea M, Freilij Hector, Schijman Alejandro G
Laboratorio de Biología Molecular de la Enfermedad de Chagas (LaBMECh), Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI-CONICET), Buenos Aires, Argentina.
Int J Parasitol. 2007 Oct;37(12):1319-27. doi: 10.1016/j.ijpara.2007.04.015. Epub 2007 May 10.
Congenital transmission of Trypanosoma cruzi may occur in some or all the gestations from a T. cruzi-infected mother. Variable rates of congenital transmission have been reported in different geographical areas where different parasitic strains predominate, suggesting that parasitic genotypes might play a role in the risk of congenital transmission. Moreover, in cases of transmission it is unknown if the whole maternal T. cruzi population or certain clones are preferentially transmitted by the transplacental route. In this study, bloodstream T. cruzi lineages were identified in blood samples from congenitally infected children, transmitting and non-transmitting mothers and unrelated Chagas disease patients, using improved PCR strategies targeted to nuclear genomic markers. T. cruzi IId was the prevalent genotype among 36/38 PCR-positive congenitally infected infants, 5/5 mothers who transmitted congenital Chagas disease, 12/13 mothers who delivered non-infected children and 28/34 unrelated Chagas disease patients, all coming from endemic localities of Argentina and Bolivia. These figures indicate no association between a particular genotype and vertical transmission. Furthermore, minicircle signatures from the maternal and infants' bloodstream trypanosomes were profiled by restriction fragment length polymorphism of the 330-bp PCR-amplified variable regions in seven cases of mothers and congenitally infected infants. Minicircle signatures were nearly identical between each mother and her infant/s and unique to each mother-infant/s case, a feature that was also observed in twin deliveries. Moreover, allelic size polymorphism analysis of microsatellite loci from populations transmitted to twins showed that all clones from the maternal polyclonal population were equally infective to both siblings.
克氏锥虫的先天性传播可能发生在克氏锥虫感染母亲的部分或全部妊娠过程中。在不同地理区域，由于优势寄生菌株不同，先天性传播的发生率也有所不同，这表明寄生基因型可能在先天性传播风险中起作用。此外，在传播的情况下，尚不清楚是整个母体克氏锥虫群体还是某些克隆更倾向于通过胎盘途径传播。在本研究中，使用针对核基因组标记的改进PCR策略，在先天性感染儿童、有传播和无传播的母亲以及无关的恰加斯病患者的血液样本中鉴定了血流中的克氏锥虫谱系。克氏锥虫IId是36/38例PCR阳性的先天性感染婴儿、5/5例传播先天性恰加斯病的母亲、12/13例分娩未感染儿童的母亲以及28/34例无关恰加斯病患者中的主要基因型，所有这些患者均来自阿根廷和玻利维亚的流行地区。这些数据表明特定基因型与垂直传播之间没有关联。此外，通过对7例母亲和先天性感染婴儿的330 bp PCR扩增可变区进行限制性片段长度多态性分析，对母体和婴儿血流锥虫的微小环特征进行了分析。每个母亲与其婴儿之间的微小环特征几乎相同，且每个母婴对都是独特的，这一特征在双胎分娩中也有观察到。此外，对传播给双胞胎的群体的微卫星位点进行等位基因大小多态性分析表明，母体多克隆群体中的所有克隆对两个兄弟姐妹的感染性相同。
