National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan.
PLoS Negl Trop Dis. 2012;6(8):e1800. doi: 10.1371/journal.pntd.0001800. Epub 2012 Aug 28.
The presence of animal reservoirs in Schistosoma japonicum infection has been a major obstacle in the control of schistosomiasis. Previous studies have proven that the inclusion of control measures on animal reservoir hosts for schistosomiasis contributed to the decrease of human cases. Animal surveillance should therefore be included to strengthen and improve the capabilities of current serological tests.
METHODOLOGY/PRINCIPAL FINDINGS: Thioredoxin peroxidase-1 (SjTPx-1) and four tandem repeat proteins (Sj1TR, Sj2TR, Sj4TR, Sj7TR) were initially evaluated against human sera. The previous test showed high sensitivity and specificity for antibody detection against SjTPx-1 and Sj7TR. In this study, the immunodiagnostic potential of these recombinant proteins was evaluated using enzyme-linked immunoassay on 50 water buffalo serum samples collected in Cagayan, the Philippines as compared with the soluble egg antigen (SEA). For specificity, 3 goat serum samples positive with Fasciola hepatica were used and among the antigens used, only SEA showed cross-reaction. Stool PCR targeting the S. japonicum 82 bp mitochondrial NAD 1 gene was done to confirm the true positives and served as the standard test. Twenty three samples were positive for stool PCR. SjTPx-1 and Sj1TR gave the highest sensitivity among the recombinant proteins tested for water buffalo samples with 82.61% and 78.26% respectively which were higher than that of SEA (69.57%).
CONCLUSIONS/SIGNIFICANCE: These results prove that SjTPx-1 works both for humans and water buffaloes making it a good candidate antigen for zoonotic diagnosis. Sj1TR showed good results for water buffaloes and therefore can also be used as a possible candidate for detecting animal schistosome infection.
动物作为日本血吸虫感染的宿主一直是血吸虫病防治的主要障碍。先前的研究已经证明，将血吸虫病动物宿主的控制措施纳入其中有助于减少人类病例。因此，应进行动物监测，以加强和改进当前血清学检测的能力。
方法/主要发现：最初评估了硫氧还蛋白过氧化物酶-1（SjTPx-1）和四个串联重复蛋白（Sj1TR、Sj2TR、Sj4TR、Sj7TR）对人血清的反应。先前的测试表明，SjTPx-1 和 Sj7TR 抗体检测具有很高的敏感性和特异性。在这项研究中，使用酶联免疫吸附试验（ELISA）对来自菲律宾卡加延的 50 份水牛血清样本进行了这些重组蛋白的免疫诊断潜力评估，与可溶性虫卵抗原（SEA）进行了比较。在特异性方面，使用 3 份山羊血清样本进行了与 Fasciola hepatica 阳性的检测，在所使用的抗原中，只有 SEA 显示出交叉反应。针对日本血吸虫 82 bp 线粒体 NAD 1 基因的粪便 PCR 用于确认真正的阳性结果，并作为标准检测。23 个样本的粪便 PCR 呈阳性。SjTPx-1 和 Sj1TR 对水牛样本的检测敏感性最高，分别为 82.61%和 78.26%，高于 SEA（69.57%）。
结论/意义：这些结果证明 SjTPx-1 对人类和水牛都有效，使其成为人畜共患病诊断的良好候选抗原。Sj1TR 对水牛的结果较好，因此也可作为检测动物血吸虫感染的可能候选抗原。
