Schols Ruben, Carolus Hans, Hammoud Cyril, Mulero Stephen, Mudavanhu Aspire, Huyse Tine
Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Leuven, Belgium.
Department of Biology, Royal Museum for Central Africa, Leuvensesteenweg 13, Tervuren, Belgium.
Trans R Soc Trop Med Hyg. 2019 Nov 1;113(11):722-729. doi: 10.1093/trstmh/trz067.
Studying the epidemiology of schistosomiasis-the most prevalent gastropod-borne human disease and an economic burden for the livestock industry-relies on adequate monitoring tools. Here we describe a molecular assay for detecting human and animal African schistosome species in their planorbid gastropod host (xenomonitoring) using a two-step approach. First, schistosome infections are detected and discriminated from other trematode infections using a multiplex polymerase chain reaction (PCR) that includes a trematode-specific marker (in 18S rDNA), a Schistosoma genus-specific marker (in internal transcribed spacer 2 [ITS2]) and a general gastropod marker (in 18S rDNA) as an internal control. Upon Schistosoma sp. detection, a second multiplex PCR is performed to discriminate among Schistosoma haematobium, Schistosoma mansoni, Schistosoma mattheei and Schistosoma bovis/Schistosoma curassoni/Schistosoma guineensis using markers of differential lengths in the cytochrome c oxidase subunit 1 (COX1) gene. The specificity of these assays was validated with adult worms, naturally infected gastropods and human urine and stool samples. Sensitivity was tested on experimentally infected snail specimens that were sacrificed 10 and 40 days post-infection in order to mimic a natural prepatent and mature infection, respectively. The assay provides a diagnostic tool to support the xenomonitoring of planorbid gastropods for trematode infections in a One Health context, with a focus on the transmission monitoring of schistosomiasis.
研究血吸虫病的流行病学——这是最常见的由腹足纲动物传播的人类疾病，也是畜牧业的经济负担——依赖于适当的监测工具。在此，我们描述了一种分子检测方法，该方法采用两步法在其扁卷螺腹足纲宿主中检测人和动物的非洲血吸虫物种（异源监测）。首先，使用多重聚合酶链反应（PCR）检测血吸虫感染并与其他吸虫感染相区分，该反应包括一个吸虫特异性标记（在18S rDNA中）、一个血吸虫属特异性标记（在内转录间隔区2 [ITS2]中）和一个通用的腹足纲标记（在18S rDNA中）作为内部对照。一旦检测到血吸虫属，进行第二次多重PCR，使用细胞色素c氧化酶亚基1（COX1）基因中不同长度的标记来区分埃及血吸虫、曼氏血吸虫、马修血吸虫和牛血吸虫/几内亚血吸虫/库拉索血吸虫。这些检测方法的特异性通过成虫、自然感染的腹足纲动物以及人类尿液和粪便样本进行了验证。敏感性在实验感染的蜗牛标本上进行了测试，分别在感染后10天和40天处死这些标本，以模拟自然的潜伏期和成熟感染。该检测方法提供了一种诊断工具，以支持在“同一健康”背景下对扁卷螺腹足纲动物进行吸虫感染的异源监测，重点是血吸虫病的传播监测。
