Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, College of Health Sciences, University of Ghana, P.O. Box 0s123, Osu, Accra, Ghana.
Malar J. 2018 Feb 23;17(1):92. doi: 10.1186/s12936-018-2231-7.
Plasmodium falciparum, the most dominant species in sub-Saharan Africa, causes the most severe clinical malaria manifestations. In resource-limited Ghana, where malaria and HIV geographically overlap, histidine-rich protein 2 (HRP2)-based rapid diagnostic test (RDT) is a faster, easier and cheaper alternative to clinical gold standard light microscopy. However, mutations in parasite hrp2 gene may result in missed infections, which have severe implications for malaria control.
The performance of a common HRP2-based RDT and expert light microscopy in HIV-positive and HIV-negative children under 5 years old was compared with PCR as laboratory gold standard. Finger-prick capillary blood was tested with First Response Malaria Ag P. falciparum (HRP2). Giemsa-stained thick and thin blood films were examined with ≥ 200 high power fields and parasites counted per 200 white blood cells. Nested PCR species identification of P. falciparum was performed and resolved on agarose gel. False negatives from RDT were further tested for deleted pfhrp2/3 and flanking genes, using PCR. The study was performed in two anti-retroviral therapy clinics in Accra and Atibie.
Out of 401 participants enrolled, 150 were HIV positive and 251 HIV negative. Malaria was more prevalent in children without HIV. Microscopy had a higher sensitivity [100% (99-100)] than RDT [83% (53.5-100)]. Parasites with pfhrp2/3 deletions contributed to missed infections from RDT false negatives.
Circulation of malaria parasites with pfrhp2/3 deletions in this population played a role in missed infections with RDT. This ought to be addressed if further strides in malaria control are to be made.
恶性疟原虫是撒哈拉以南非洲最主要的疟原虫种，可引起最严重的临床疟疾症状。在加纳，疟疾和艾滋病毒在地理上重叠，资源有限，基于组氨酸丰富蛋白 2（HRP2）的快速诊断检测（RDT）是替代临床金标准显微镜检查的更快、更容易和更便宜的方法。然而，寄生虫 HRP2 基因的突变可能导致漏检，这对疟疾控制有严重影响。
比较了一种常见的基于 HRP2 的 RDT 和专家显微镜检查在 5 岁以下 HIV 阳性和 HIV 阴性儿童中的表现，以聚合酶链反应（PCR）为实验室金标准。用 First Response 疟疾 Ag P. falciparum（HRP2）检测指尖毛细血管血。用 Giemsa 染色的厚、薄血膜，用 200 倍高倍视野检查，每 200 个白细胞计数寄生虫。对 P. falciparum 进行巢式 PCR 种属鉴定，并在琼脂糖凝胶上进行解析。对 RDT 的假阴性进一步用 PCR 检测缺失的 pfhrp2/3 和侧翼基因。该研究在阿克拉和阿提比的两个抗逆转录病毒治疗诊所进行。
在纳入的 401 名参与者中，有 150 名 HIV 阳性，251 名 HIV 阴性。无 HIV 的儿童中疟疾更为常见。显微镜检查的敏感性[100%（99-100）]高于 RDT[83%（53.5-100）]。RDT 假阴性的原因是存在 pfhrp2/3 缺失的疟原虫。
在该人群中，pfhrp2/3 缺失的疟原虫循环导致 RDT 漏检。如果要进一步推进疟疾控制，就必须解决这一问题。
