Combination of Kato-Katz faecal examinations and ELISA to improve accuracy of diagnosis of intestinal schistosomiasis in a low-endemic setting in Brazil
Combination of Kato-Katz faecal examinations and ELISA to improve accuracy of diagnosis of intestinal schistosomiasis in a low-endemic setting in Brazil
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DOI：
10.1016/j.actatropica.2010.05.007
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发表时间：
2011-09-01
期刊：
影响因子：
2.7
通讯作者：
Moraes Bezerra, Fernando Schemelzer
中科院分区：
文献类型：
--
作者：
da Frota, Sabrina Menezes;Carneiro, Teiliane Rodrigues;Moraes Bezerra, Fernando Schemelzer
考虑到许多流行地区肠道血吸虫病造成的疾病负担减轻，需要更灵敏的诊断方法来规划和监测控制措施。我们在巴西东北部的一个农村社区（317 名居民）进行了一项横断面调查。采用了包括重复粪便检查和 ELISA 检测在内的综合方法。在第一轮中，从 305 名（96.2%）参与者收集了单次粪便样本。每个样品制备三张 Kato-Katz (KK) 涂片，并从血清样品中进行 IgG ELISA。在 KK 涂片阴性但 ELISA 结果呈阳性的 85 例病例中，第二轮又收集了 3 份粪便样本，并准备了另外 5 份 KK 涂片。在第一轮 KK 分析中，11/287（3.8%；95% 置信区间；1.92-6.75）呈阳性。在对每个人进行最多八次涂片检查（第二轮）后，血吸虫病患病率增加至 8.7%（95% 置信区间：5.9-12.5）。总共 96/287 个（33.4%，95% 置信区间：28.0-39.2）样本经 ELISA 检测呈阳性。没有出现假阴性 ELISA 结果。与来自三个粪便样本的多达八个 KK 涂片（参考诊断）相比，ELISA 的特异性、阳性和阴性预测值分别为 72.9%、26.0% 和 100%。一次 KK 涂片检查仅检测出 25 例感染中的 12%；这一比例增加至 44%（三份涂片，一份粪便样本）、84%（五份涂片，三份粪便样本）和 96%（六份涂片，四份粪便样本）。我们的结论是，在巴西低流行地区，KK 的使用仍然是一个重要的工具。从重复的粪便样本中制备六张以上 KK 涂片的额外好处可以忽略不计。 ELISA 可用于筛查人群，随后通过 KK 或其他更敏感但高度特异性的方法确认诊断。 (C) 2010 Elsevier B.V. 保留所有权利。
Considering the decrease of disease burden caused by intestinal schistosomiasis in many endemic settings, more sensitive diagnostic methods are needed to plan and monitor control measures. We conducted a cross-sectional survey in a rural community in northeast Brazil (317 inhabitants). A combined approach including repeated faecal examinations and ELISA testing was applied. In a first round, single stool samples were collected from 305(96.2%) participants. Three Kato-Katz (KK) smears were prepared from each sample, and IgG ELISA was performed from serum samples. In the 85 cases of negative KK smears, but positive ELISA results, three additional faecal samples were collected in a second round, and another five KK smears prepared. In the first round of KK analysis, 11/287 (3.8%; 95% confidence interval; 1.92-6.75) were positive. After examining up to eight smears per individual (second round), prevalence of schistosomiasis increased to 8.7% (95% confidence interval: 5.9-12.5). In total, 96/287 (33.4%, 95% confidence interval: 28.0-39.2) samples were positive by ELISA testing. There were no false negative ELISA results. Specificity, positive and negative predictive values of ELISA as compared to up to eight KK smears from three stool samples (reference diagnosis) were 72.9%, 26.0% and 100%, respectively. A single KK smear detected only 12% of the 25 infections; this increased to 44% (three smears, one stool sample), 84% (five smears, three stool samples) and 96% (six smears, four stool samples). We conclude that in low-endemic areas in Brazil the use of KK continues being an important tool. The additional benefit of preparing more than six KK smears from repeated stool samples is negligible. ELISA may be useful for screening populations, with subsequent confirmation of diagnosis by KK or other more sensitive, but highly specific methods. (C) 2010 Elsevier B.V. All rights reserved.