Background

The Global Programme to Eliminate Lymphatic Filariasis uses point-of-care tests for circulating filarial antigenemia (CFA) to map endemic areas and for monitoring and evaluating the success of mass drug administration (MDA) programs. We compared the performance of the reference BinaxNOW Filariasis card test (ICT, introduced in 1997) with the Alere Filariasis Test Strip (FTS, introduced in 2013) in 5 endemic study sites in Africa.

Methodology

The tests were compared prior to MDA in two study sites (Congo and Côte d'Ivoire) and in three sites that had received MDA (DRC and 2 sites in Liberia). Data were analyzed with regard to % positivity, % agreement, and heterogeneity. Models evaluated potential effects of age, gender, and blood microfilaria (Mf) counts in individuals and effects of endemicity and history of MDA at the village level as potential factors linked to higher sensitivity of the FTS. Lastly, we assessed relationships between CFA scores and Mf in pre- and post-MDA settings.

Principal findings

Paired test results were available for 3,682 individuals. Antigenemia rates were 8% and 22% higher by FTS than by ICT in pre-MDA and in post-MDA sites, respectively. FTS/ICT ratios were higher in areas with low infection rates. The probability of having microfilaremia was much higher in persons with CFA scores >1 in untreated areas. However, this was not true in post-MDA settings.

Conclusions/Significance

This study has provided extensive new information on the performance of the FTS compared to ICT in Africa and it has confirmed the increased sensitivity of FTS reported in prior studies. Variability in FTS/ICT was related in part to endemicity level, history of MDA, and perhaps to the medications used for MDA. These results suggest that FTS should be superior to ICT for mapping, for transmission assessment surveys, and for post-MDA surveillance.

中文翻译：

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多中心现场研究非洲循环性吴氏疟原虫抗原血症的两个即时检验

背景

《消除淋巴丝虫病全球计划》使用即时检验来检测循环丝虫抗原血症（CFA），以绘制流行地区图，并监测和评估大规模药物管理（MDA）计划的成功。我们将参考BinaxNOW丝虫病卡片测试（ICT，于1997年推出）与Alere丝虫病测试条（FTS，于2013年推出）在非洲5个地方病研究地点的性能进行了比较。

方法

在进行MDA之前，在两个研究地点（刚果和科特迪瓦）和接受MDA的三个地点（DRC和利比里亚的2个地点）对测试进行了比较。分析有关阳性率，一致性和异质性的数据。模型评估了个体中年龄，性别和血液微丝aria（Mf）计数的潜在影响以及乡村水平上MDA的流行性和历史的影响，将其作为与FTS敏感性更高相关的潜在因素。最后，我们评估了MDA前后的CFA评分与Mf之间的关系。

主要发现

配对测试结果可用于3,682个人。在MDA之前和MDA之后的地区，FTS的抗原血症发生率分别比ICT高8％和22％。在感染率较低的地区，FTS / ICT比率较高。在未经治疗的地区，CFA评分> 1的人发生微丝虫病的可能性要高得多。但是，在MDA后的设置中情况并非如此。

结论/意义

这项研究提供了有关FTS与非洲ICT相比性能的大量新信息，并且证实了先前研究中报道的FTS的敏感性提高了。FTS / ICT的可变性部分与流行程度，MDA的历史有关，也许与MDA所用的药物有关。这些结果表明，FTS在制图，传输评估调查和MDA后监视方面应优于ICT。