评价循环阴极抗原（CCA）尿液检测在喀麦隆诊断曼氏血吸虫感染的应用。
Evaluation of circulating cathodic antigen (CCA) urine-tests for diagnosis of Schistosoma mansoni infection in Cameroon.
机构信息
Centre for Schistosomiasis and Parasitology, Yaoundé, Cameroon.
出版信息
PLoS Negl Trop Dis. 2012;6(7):e1758. doi: 10.1371/journal.pntd.0001758. Epub 2012 Jul 31.
BACKGROUND
The Kato-Katz is the most common diagnostic method for Schistosoma mansoni infection. However, the day-to-day variability in host egg-excretion and its low detection sensitivity are major limits for its use in low transmission zones and after widespread chemotherapy. We evaluated the accuracy of circulating cathodic antigen (CCA) urine-assay as a diagnostic tool of S. mansoni. In comparison, a low sensitive CCA test (CCA-L) was assessed.
METHODOLOGY
THE STUDY WAS CONDUCTED IN THREE SETTINGS: two foci with single S. mansoni infections (settings A and B), and one mixed S. mansoni - S. haematobium focus (setting C). Stool and urine samples were collected from school-children on three consecutive days. Triplicate Kato-Katz readings were performed per stool sample. Each urine sample was tested with one CCA and only the first urine sample was subjected to CCA-L. Urine samples were also examined for S. haematobium eggs using the filtration method and for microhaematuria using urine reagent strips. Overall, 625 children provided three stool and three urine samples.
PRINCIPAL FINDINGS
Considering nine Kato-Katz thick smears as 'reference' diagnostic test, the prevalence of S. mansoni was 36.2%, 71.8% and 64.0% in settings A, B and C, respectively. The prevalence of S. haematobium in setting C was 12.0%. The sensitivities of single Kato-Katz, CCA and CCA-L from the first stool or urine samples were 58%, 82% and 46% in setting A, 56.8%, 82.4% and 68.8% in setting B, and 49.0%, 87.7% and 55.5% in setting C. The respective specificities were 100%, 64.7% and 100%; 100%, 62.3% and 91.3%; and 100%, 42.5% and 92.0%. Mixed infection with S. haematobium did not influence the CCA test results for S. mansoni diagnosis.
CONCLUSIONS/SIGNIFICANCE: Urine CCA revealed higher sensitivity than CCA-L and triplicate Kato-Katz, and produced similar prevalence as nine Kato-Katz. It seems an attractive method for S. mansoni diagnosis.
背景
加藤厚涂片法是曼氏血吸虫感染最常用的诊断方法。然而，宿主粪便中虫卵的日变异性及其低检测灵敏度是其在低传播区和广泛化疗后使用的主要限制。我们评估了循环阴极抗原（CCA）尿液检测作为曼氏血吸虫诊断工具的准确性。相比之下，评估了一种低灵敏度的 CCA 检测（CCA-L）。
方法
该研究在三个环境中进行：两个单一曼氏血吸虫感染焦点（环境 A 和 B）和一个曼氏血吸虫-埃及血吸虫混合感染焦点（环境 C）。从在校儿童中连续三天采集粪便和尿液样本。每份粪便样本进行三次加藤厚涂片检测。每个尿液样本均用一个 CCA 检测，仅第一个尿液样本用 CCA-L 检测。尿液样本还使用过滤法检测埃及血吸虫卵，并使用尿液试剂条检测微血尿。总共 625 名儿童提供了三份粪便和三份尿液样本。
主要发现
以九张加藤厚涂片作为“参考”诊断试验，在环境 A、B 和 C 中，曼氏血吸虫的流行率分别为 36.2%、71.8%和 64.0%。环境 C 中埃及血吸虫的流行率为 12.0%。单次加藤厚涂片、第一次粪便或尿液样本的 CCA 和 CCA-L 的灵敏度在环境 A 中分别为 58%、82%和 46%，在环境 B 中分别为 56.8%、82.4%和 68.8%，在环境 C 中分别为 49.0%、87.7%和 55.5%。各自的特异性分别为 100%、64.7%和 100%；100%、62.3%和 91.3%；和 100%、42.5%和 92.0%。埃及血吸虫混合感染并不影响 CCA 检测对曼氏血吸虫诊断的结果。
结论/意义：尿液 CCA 的灵敏度高于 CCA-L 和三次加藤厚涂片法，且与九次加藤厚涂片法的流行率相似。它似乎是一种有吸引力的曼氏血吸虫诊断方法。
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