Additional evaluation of the point-of-contact circulating cathodic antigen assay for Schistosoma mansoni infection
Additional evaluation of the point-of-contact circulating cathodic antigen assay for Schistosoma mansoni infection
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DOI：
10.3389/fpubh.2015.00048
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发表时间：
2015-01-01
影响因子：
5.2
通讯作者：
Colley, Daniel G.
中科院分区：
文献类型：
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作者：
Mwinzi, Pauline N. M.;Kittur, Nupur;Colley, Daniel G.
在非洲曼氏血吸虫流行环境中进行的基于尿液的接触点阴极循环抗原试验（POC-CCA）的研究表明，该试验在检测感染方面具有良好的灵敏度，但在低流行率地区，POC-CCA可用于Kato-Katz粪便检测虫卵阴性的人。我们检查了POC-CCA检测的以下方面：（a）批次间稳定性;（B）读片员内和读片员间变异性;（c）与Kato-Katz粪便检测相比的每日变异性，以及（d）观察吡喹酮（PZQ）治疗是否将Kato-Katz阴性/POC-CCA阳性个体转化为POC-CCA阴性。我们发现基本上没有批次间差异，阅片员内差异可忽略不计（2%），阅片员间可靠性基本一致。在5天的尿液采集中观察到一些日间变化，但小于3天内Kato-Katz粪便测定的变化。为了评价治疗对Kato-Katz（-）/POC-CCA（+）儿童的影响，在患病率为10-15%的地区招募了149名儿童，这些儿童根据3份粪便样本为Kato-Katz（-），但POCCCA（+）。给药后7天（PZQ 40 mg/kg），再次采集样品并进行检测。近一半（47%）POC-CCA阳性儿童转为阴性。那些仍然POC-CCA阳性的人接受了第二次治疗，其中34%的人在第二次治疗后转为POC-CCA阴性。大多数保持POC-CCA阳性的人每次都会转移到“较低”的POC-CCA“阳性水平。“数据表明，大多数Kato-Katz阴性/POC-CCA阳性个体具有低强度感染，每次治疗都会杀死所有或部分蠕虫。数据还表明，当通过更敏感的检测进行评估时，PZQ的有效治愈率显著低于从粪便检测推断的治愈率。这些发现对血吸虫感染的绘图和监测以及计划从血吸虫病发病率控制到消除传播的过渡具有公共卫生意义。
Studies of the urine-based point-of-contact cathodic circulating antigen test (POC-CCA) in Schistosoma mansoni-endemic settings in Africa indicate it has good sensitivity in detecting infections, but in areas of low prevalence, the POC-CCA can be positive for persons who are egg-negative by Kato-Katz stool assays. We examined the POC-CCA assay for: (a) batch-to-batch stability; (b) intra-reader and inter-reader variability; (c) day-to-day variability compared to Kato-Katz stool assays, and (d) to see if praziquantel (PZQ) treatment converted Kato-Katz-negative/POC-CCA positive individuals to POC-CCA negativity. We found essentially no batch-to-batch variation, negligible intra-reader variability (2%), and substantial agreement for inter-reader reliability. Some day-to-day variation was observed over 5 days of urine collection, but less than the variation in Kato-Katz stool assays over 3 days. To evaluate the effect of treatment on Kato-Katz(-)/P0C-CCA(+) children, 149 children in an area of 10-15% prevalence who were Kato-Katz(-) based on 3 stool samples but POCCCA(+) were enrolled. Seven days after treatment (PZQ 40 mg/kg) samples were again collected and tested. Almost half (47%) POC-CCA positive children turned negative. Those still POC-CCA positive received a second treatment, and 34% of them turned POC-CCA negative upon this second treatment. Most who remained POC-CCA positive shifted each time to a "lesser" POC-CCA "level of positivity." The data suggest that most Kato-Katznegative/POC-CCA positive individuals harbor low-intensity infections, and each treatment kills all or some of their adult worms. The data also suggest that when evaluated by a more sensitive assay, the effective cure rates for PZQ are significantly less than those inferred from fecal testing. These findings have public health significance for the mapping and monitoring of Schistosoma infections and in planning the transition from schistosomiasis morbidity control to elimination of transmission.