Aschar Mariana, Sanchez Maria Carmen A, Costa-Nascimento Maria de Jesus, Farinas Maria de Lourdes R N, Hristov Angélica D, Lima Giselle F M C, Inoue Juliana, Levi José E, Di Santi Silvia M
Faculdade de Medicina Universidade de São Paulo São Paulo Brazil Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo São Paulo Brazil Instituto de Medicina Tropical da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
Rev Panam Salud Publica. 2022 Mar 28;46:e11. doi: 10.26633/RPSP.2022.11. eCollection 2022.
To evaluate molecular tools to detect low-level parasitemia and the five species of that infect humans for use in control and elimination programs, and in reference laboratories.
We evaluated 145 blood samples from patients who tested positive by nested polymerase chain reaction (nPCR), from asymptomatic individuals and from the WHO Global Malaria Programme/United Kingdom National External Quality Assessment Service. Samples were assayed using the genus-specific RealStar Malaria PCR Kit 1.0 (alt-Gen; altona Diagnostics) and the RealStar Malaria Screen & Type PCR Kit (alt-S&T; altona Diagnostics). The results from the molecular tests were compared with those from quantitative PCR (qPCR), nPCR and thick blood smear.
The levels of parasitemia ranged from 1 to 518 000 parasites/µL, depending on the species. Compared with nPCR, alt-S&T had a sensitivity of 100%, except for identifying , for which the sensitivity was 93.94%. All samples positive by alt-Gen were also positive by nPCR. When comparing alt-Gen to qPCR, the sensitivity was 100% for and . For all species, the correlation between cycle threshold values of alt-S&T and alt-Gen compared with qPCR was significant ( < 0.0001, Spearman's test), with = 0.8621 for alt-S&T and = 0.9371 for alt-Gen. When all species were considered, there was a negative correlation between the level of parasitemia and real-time PCR cycle threshold values ( < 0.0001). In this study, only 2 of 28 samples from asymptomatic individuals were positive by thick blood smear; however, all 28 of these samples were positive by alt-S&T.
The alt-Gen and alt-S&T assays are suitable for detecting submicroscopic infections for distinct epidemiological purposes, such as for use in surveys and reference laboratories, and screening in blood banks, which will contribute to global efforts to eliminate malaria.
评估用于检测低水平寄生虫血症以及感染人类的五种疟原虫的分子工具，以便在疟疾控制和消除计划以及参考实验室中使用。
我们评估了145份血液样本，这些样本来自通过巢式聚合酶链反应（nPCR）检测呈阳性的患者、无症状个体以及世界卫生组织全球疟疾项目/英国国家外部质量评估服务机构。使用属特异性的RealStar疟疾PCR试剂盒1.0（alt-Gen；阿尔托纳诊断公司）和RealStar疟疾筛查与分型PCR试剂盒（alt-S&T；阿尔托纳诊断公司）对样本进行检测。将分子检测结果与定量PCR（qPCR）、nPCR和厚血涂片检测结果进行比较。
寄生虫血症水平因疟原虫种类而异，范围为1至518000个寄生虫/微升。与nPCR相比，alt-S&T的灵敏度为100%，但在鉴定某一疟原虫时，其灵敏度为93.94%。所有经alt-Gen检测呈阳性的样本经nPCR检测也呈阳性。将alt-Gen与qPCR比较时，对某两种疟原虫的灵敏度为100%。对于所有疟原虫种类，alt-S&T和alt-Gen的循环阈值与qPCR之间的相关性均具有显著性（P<0.0001，Spearman检验），alt-S&T的r值为0.8621，alt-Gen的r值为0.9371。当考虑所有疟原虫种类时，寄生虫血症水平与实时PCR循环阈值之间呈负相关（P<0.0001）。在本研究中，28份无症状个体的样本中只有2份经厚血涂片检测呈阳性；然而，这28份样本经alt-S&T检测均呈阳性。
alt-Gen和alt-S&T检测方法适用于检测不同流行病学目的的亚显微镜感染，例如用于调查和参考实验室以及血库筛查，这将有助于全球消除疟疾的努力。
