Unité de Formation et de Recherche Biosciences, Laboratoire de Biologie et Santé, Université Félix Houphouët-Boigny, Abidjan 01, 01 BP V34, Côte d'Ivoire.
Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan 01, 01 BP 1303, Côte d'Ivoire.
Malar J. 2022 Apr 2;21(1):111. doi: 10.1186/s12936-022-04133-6.
Highly sensitive and accurate malaria diagnostic tools are essential to identify asymptomatic low parasitaemia infections. This study evaluated the performance of histidine-rich protein 2 (HRP-2) based rapid diagnostic tests (RDTs), microscopy and loop-mediated isothermal amplification (LAMP) for the detection of asymptomatic Plasmodium spp. infections in Northern Côte d'Ivoire, using nested polymerase chain reaction (nPCR) as reference.
A household-based survey was carried out in July 2016, in the health district of Korhogo, involving 1011 adults without malaria symptom nor history of fever during the week before recruitment. The fresh capillary blood samples were collected to detect Plasmodium infections using on HRP-2-based RDTs, microscopy and LAMP and stored as dried blood spots (DBS). A subset of the DBS (247/1011, 24.4%) was randomly selected for nPCR analyses. Additionally, venous blood samples, according to LAMP result (45 LAMP positive and 65 LAMP negative) were collected among the included participants to perform the nested PCR used as the reference.
The prevalence of asymptomatic Plasmodium spp. infections determined by RDT, microscopy, and LAMP were 4% (95% confidence interval (CI) 2.8-5.3), 5.2% (95% CI 3.9-6.6) and 18.8% (95% CI 16.4-21.2), respectively. Considering PCR on venous blood as reference, performed on 110 samples, the sensibility and specificity were, respectively, 17.8% (95% CI 6.1-29.4) and 100% for RDT, 20.0% (95% CI 7.8-32) and 100% for microscopy, and 93.3% (95% CI 85.7-100) and 95.4% (95% CI 92.2-100) for LAMP.
In Northern Côte d'Ivoire, asymptomatic Plasmodium infection was found to be widely distributed as approximately one out of five study participants was found to be Plasmodium infected. LAMP appears currently to be the only available diagnostic method that can identify in the field this reservoir of infections and should be the method to consider for potential future active case detection interventions targeting elimination of these infections.
高度敏感和准确的疟疾诊断工具对于识别无症状低寄生虫血症感染至关重要。本研究使用巢式聚合酶链反应（nPCR）作为参考，评估了在科特迪瓦北部用于检测无症状疟原虫感染的基于组氨酸丰富蛋白 2（HRP-2）的快速诊断检测（RDT）、显微镜检查和环介导等温扩增（LAMP）的性能。
2016 年 7 月，在科霍戈卫生区进行了一项以家庭为基础的调查，涉及 1011 名无疟疾症状且在招募前一周内无发热史的成年人。采集新鲜的毛细血管血样，使用基于 HRP-2 的 RDT、显微镜检查和 LAMP 检测疟原虫感染，并作为干血斑（DBS）储存。从这些 DBS 中随机选择了一部分（247/1011，24.4%）进行 nPCR 分析。此外，根据 LAMP 结果（45 个 LAMP 阳性和 65 个 LAMP 阴性），从纳入的参与者中采集静脉血样本，以进行作为参考的巢式 PCR。
通过 RDT、显微镜检查和 LAMP 确定的无症状疟原虫感染的患病率分别为 4%（95%置信区间[CI]2.8-5.3）、5.2%（95%CI3.9-6.6）和 18.8%（95%CI16.4-21.2）。考虑到对 110 个样本进行静脉血 PCR 作为参考，RDT 的敏感性和特异性分别为 17.8%（95%CI6.1-29.4）和 100%，显微镜检查的敏感性和特异性分别为 20.0%（95%CI7.8-32）和 100%，LAMP 的敏感性和特异性分别为 93.3%（95%CI85.7-100）和 95.4%（95%CI92.2-100）。
在科特迪瓦北部，无症状的疟原虫感染分布广泛，大约五分之一的研究参与者被发现感染了疟原虫。目前，LAMP 似乎是唯一可在现场识别这种感染源的诊断方法，应该成为未来针对消除这些感染的潜在主动病例检测干预措施的考虑方法。
