Pontifícia Universidade Católica do Rio Grande do Sul, Escola de Ciências, Departamento de Ecologia e Biodiversidade, Porto Alegre, RS, Brasil.
University of Western Australia, Department of Physics, Perth, Australia.
Rev Soc Bras Med Trop. 2020 Oct 5;53:e20200411. doi: 10.1590/0037-8682-0411-2020. eCollection 2020.
Brazil's southernmost state, Rio Grande do Sul (RGS), was considered schistosomiasis-free until 1998 when a low endemic focus was identified in Esteio, a city located next to the capital of RGS. In the last two decades, the control interventions applied in the region have been apparently successful, and the absence of new cases indicated the possibility of interrupted schistosomiasis transmission. The objective of this study was to update the clinical and epidemiological data of schistosomiasis in Esteio.
We reviewed all 28 individuals diagnosed with the infection since 1997 and a survey was applied to a group of 29 school-aged children residing in Vila Pedreira, one of the most affected neighborhoods.
No eggs were detected in fecal samples using the Helmintex method, and all samples were negative for serum antibodies on examination by the western blot technique using the Schistosoma mansoni microsomal antigen (MAMA- WB). In contrast, 23 individuals (79%) tested positive for the cathodic circulating antigen with the point-of-care immunochromatographic test (POC-CCA) on urine samples. Of the 28 formerly infected individuals, only eight were located, of which four tested positive, and four tested negative for serum antibodies using the MAMA-WB technique.
Current adverse conditions for S. mansoni transmission in Esteio and the absence of a confirmed diagnosis suggests that there is (i) a lack of specificity of the POC-CCA test in low endemic settings, and (ii) a high probability that interruption of schistosomiasis has been achieved in Esteio.
巴西最南部的南里奥格兰德州（RGS）直到 1998 年才被认为没有血吸虫病，当时在 RGS 首府附近的埃斯特埃奥（Esteio）发现了一个低流行焦点。在过去的二十年中，该地区应用的控制干预措施显然取得了成功，并且没有新病例表明血吸虫病传播可能已中断。本研究的目的是更新埃斯特埃奥血吸虫病的临床和流行病学数据。
我们回顾了自 1997 年以来诊断出的所有 28 例感染者的资料，并对居住在受影响最严重的街区之一 Vila Pedreira 的 29 名学龄儿童进行了调查。
使用 Helmintex 方法在粪便样本中未检测到虫卵，并且在用曼氏血吸虫微粒体抗原（MAMA-WB）进行的 Western blot 技术检查时，所有样本的血清抗体均为阴性。相比之下，23 名个体（79％）的尿液样本用即时免疫层析试验（POC-CCA）检测到阴转循环抗原呈阳性。在 28 名以前感染的个体中，只有 8 名被找到，其中 4 名使用 MAMA-WB 技术检测血清抗体呈阳性，4 名呈阴性。
目前埃斯特埃奥不利于曼氏血吸虫传播的不利条件以及缺乏确诊诊断表明（i）POC-CCA 试验在低流行地区的特异性不足，（ii）埃斯特埃奥很有可能已中断血吸虫病传播。
