Ostermayer Alejandro Luquetti, Passos Afonso Dinis Costa, Silveira Antônio Carlos, Ferreira Antonio Walter, Macedo Vanize, Prata Aluízio Rosa
Laboratório de Doença de Chagas, Hospital das Clínicas, Universidade Federal de Goiás, Goiânia, GO, Brazil.
Rev Soc Bras Med Trop. 2011;44 Suppl 2:108-21. doi: 10.1590/s0037-86822011000800015.
A survey for seroprevalence of Chagas disease was held in a representative sample of Brazilian individuals up to 5 years of age in all the rural areas of Brazil, with the single exception of Rio de Janeiro State. Blood on filter paper was collected from 104,954 children and screened in a single laboratory with two serological tests: indirect immunofluorescence and enzyme linked immunoassay. All samples with positive or indetermined results, as well as 10% of all the negative samples were submitted to a quality control reference laboratory, which performed both tests a second time, as well as the western blot assay of TESA (Trypomastigote Excreted Secreted Antigen). All children with confirmed final positive result (n = 104, prevalence = 0.1%) had a follow-up visit and were submitted to a second blood collection, this time a whole blood sample. In addition, blood samples from the respective mothers and familiar members were collected. The infection was confirmed in only 32 (0.03%) of those children. From them, 20 (0.025%) had maternal positive results, suggesting congenital transmission; 11 (0.01%) had non-infected mothers, indicating a possible vectorial transmission; and in one whose mother had died the transmission mechanism could not be elucidated. In further 41 visited children the infection was confirmed only in their mothers, suggesting passive transference of maternal antibodies; in other 18, both child and mother were negative; and in 13 cases both were not localized. The 11 children that acquired the infection presumably through the vector were distributed mainly in the Northeast region of Brazil (States of Piauí, Ceará, Rio Grande do Norte, Paraíba and Alagoas), in addition to one case in Amazonas (North region) and another in Parana (South region). Remarkably, 60% of the 20 cases of probably congenital transmission were from a single State, Rio Grande do Sul, with the remaining cases distributed in other states. This is the first report demonstrating regional geographical differences in the vertical transmission of Chagas disease in Brazil, which probably reflects the predominant Trypanosoma cruzi group IId and IIe (now TcV and TcVI) found in this state. Overall, these results show that the regular and systematic control programs against the transmission of Chagas disease, together with socioeconomic changes observed in Brazil in the last decades, interrupted the vectorial transmission in Brazil, resumed in the few cases found in this national survey. Furthermore they reinforce the need for maintenance of control programs for the consolidation of this major advance in public health.
在巴西所有农村地区（里约热内卢州除外），对5岁及以下巴西个体的代表性样本进行了恰加斯病血清流行率调查。从104,954名儿童中采集滤纸血样，并在单个实验室用两种血清学检测方法进行筛查：间接免疫荧光法和酶联免疫吸附测定法。所有结果为阳性或不确定的样本，以及所有阴性样本的10%，都被送交质量控制参考实验室，该实验室再次进行这两种检测，并进行TESA（锥鞭毛体排泄分泌抗原）的免疫印迹分析。所有最终确诊为阳性的儿童（n = 104，患病率 = 0.1%）都进行了随访，并再次采集血样，这次采集的是全血样本。此外，还采集了各自母亲和家庭成员的血样。在这些儿童中，仅32名（0.03%）被确诊感染。其中，20名（0.025%）母亲的检测结果为阳性，提示为先天性传播；11名（0.01%）母亲未感染，表明可能为媒介传播；还有一名母亲已去世，其传播机制无法阐明。在另外41名接受随访的儿童中，仅在其母亲中确诊感染，提示为母体抗体的被动转移；在另外18名儿童中，儿童和母亲的检测结果均为阴性；在13例中，两者均未找到。这11名可能通过媒介感染的儿童主要分布在巴西东北部地区（皮奥伊州、塞阿拉州、北大河州、帕拉伊巴州和阿拉戈斯州），此外，亚马逊州（北部地区）有1例，巴拉那州（南部地区）有1例。值得注意的是，20例可能为先天性传播的病例中，60%来自南里奥格兰德州，其余病例分布在其他州。这是第一份证明巴西恰加斯病垂直传播存在区域地理差异的报告，这可能反映了该州主要发现的克氏锥虫IId和IIe组（现为TcV和TcVI）。总体而言，这些结果表明，针对恰加斯病传播的常规和系统控制项目，以及巴西过去几十年观察到的社会经济变化，中断了巴西的媒介传播，在本次全国调查中发现的少数病例中又有所恢复。此外，这些结果强化了维持控制项目以巩固这一公共卫生重大进展的必要性。
