Department of Parasitology, Leiden University Medical Center, L4-Q, PO Box 9600, 2300 RC, Leiden, The Netherlands.
Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
Eur J Clin Microbiol Infect Dis. 2018 Sep;37(9):1709-1716. doi: 10.1007/s10096-018-3303-x. Epub 2018 Jul 4.
Schistosomiasis is a parasitic disease affecting over 250 million people in the tropics. In non-endemic regions, imported Schistosoma infections are commonly diagnosed by serology, but based on antibody detection an active infection cannot be distinguished from a cured infection and it may take more than 8 weeks after exposure before seroconversion occurs. In endemic populations, excellent results have been described in diagnosing low-grade active Schistosoma infections by the detection of the adult worm-derived circulating anodic antigen (CAA) utilising robust lateral flow (LF) assays combined with up-converting phosphor (UCP) reporter technology. The purpose of this study is to explore the diagnostic value of the UCP-LF CAA assay in a non-endemic setting. CAA concentrations were determined in 111 serum samples originating from 81 serology-positive individuals. In nine individuals, serum could be collected before travel and an additional five provided samples before and after seroconversion occurred. Based on detectable CAA levels, an active infection was seen in 56/81 (69%) of the exposed individuals, while the 10 controls and the 9 sera collected before travel were tested negative for CAA. Positive CAA levels were observed starting 4 weeks after exposure and in four cases CAA was detected even before Schistosoma-specific antibodies became positive. Higher serum CAA levels were seen in migrants than in travellers and CAA concentrations dropped sharply when testing follow-up samples after treatment. This explorative study indicates the UCP-LF CAA serum assay to be a highly accurate test for detecting active low-grade Schistosoma infections in a non-endemic routine diagnostic setting.
血吸虫病是一种寄生虫病，影响着 2.5 亿以上的热带地区人口。在非流行地区，通过血清学诊断常见输入性血吸虫感染，但基于抗体检测，无法区分活动性感染和治愈性感染，且在暴露后可能需要 8 周以上才会出现血清转换。在流行地区，利用稳健的侧向流动（LF）检测结合上转换磷（UCP）报告技术检测成虫来源的循环阳极抗原（CAA），已经在诊断低级别活动性血吸虫感染方面取得了出色的结果。本研究旨在探索 UCP-LF CAA 检测在非流行地区的诊断价值。在 111 份血清样本中检测了 81 名血清学阳性个体的 CAA 浓度。在 9 名个体中，在旅行前收集了血清，另外 5 名个体在血清转换前和转换后提供了样本。根据可检测的 CAA 水平，在 81 名暴露个体中有 56 名（69%）存在活动性感染，而 10 名对照个体和旅行前采集的 9 份血清均未检测到 CAA。暴露后 4 周开始出现阳性 CAA 水平，在 4 例中甚至在出现血吸虫特异性抗体阳性之前就检测到了 CAA。移民的血清 CAA 水平高于旅行者，治疗后随访样本的 CAA 浓度急剧下降。这项探索性研究表明，UCP-LF CAA 血清检测在非流行地区的常规诊断环境中是一种高度准确的检测方法，可用于检测低级别活动性血吸虫感染。
