Department of Biomedical Sciences, School of Allied Health Sciences, University of Cape Coast, Cape Coast, Ghana.
Wellcome Sanger Institute, Hinxton, CB10 1SA, UK.
Malar J. 2019 Jun 24;18(1):214. doi: 10.1186/s12936-019-2850-7.
Undesirable consequences of donor Plasmodium falciparum parasitaemia on stored donor blood have been reported. Therefore, it is imperative that all prospective blood donors are screened for P. falciparum infections using sensitive techniques. In this study, the sensitivities of microscopy, rapid diagnostic test (RDT), loop-mediated isothermal amplification (LAMP) assay and selective whole genome amplification (sWGA) technique in detecting P. falciparum infections in blood donors was assessed.
Randomly selected blood donors from 5 districts in Greater Accra Region of Ghana were screened for asymptomatic P. falciparum infections. Each donor sample was screened with SD Bioline RDT kit for P. falciparum histidine rich protein 2 and Plasmodium lactate dehydrogenase antigens, sWGA and 18s-rRNA LAMP. Crude DNA LAMP (crDNA-LAMP) was compared to purified DNA LAMP (pDNA-LAMP).
A total of 771 blood donors were screened. The respective overall prevalence of P. falciparum in Ghana by microscopy, RDT, crDNA-LAMP, pDNA-LAMP and sWGA was 7.4%, 11.8%, 16.9%, 17.5% and 18.0%. Using sWGA as the reference test, the sensitivities of microscopy, RDT, crDNA-LAMP and pDNA-LAMP were 41.0% (95% CI 32.7-49.7), 65.5% (95% CI 56.9-73.3), 82.6% (95% CI 75.8-88.3) and 95.7% (95% CI 90.1-98.4), respectively. There was near perfect agreement between LAMP and sWGA (sWGA vs. crDNA-LAMP, κ = 0.87; sWGA vs. pDNA-LAMP, κ = 0.96), while crDNA-LAMP and pDNA-LAMP agreed perfectly (κ = 0.91). Goodness of fit test indicated non-significant difference between the performance of LAMP and sWGA (crDNA-LAMP vs. sWGA: x = 0.71, p = 0.399 and pDNA-LAMP vs. sWGA: x = 0.14, p = 0.707). Finally, compared to sWGA, the performance of LAMP did not differ in detecting sub-microscopic parasitaemia (sWGA vs. crDNA-LAMP: x = 1.12, p = 0.290 and sWGA vs. pDNA-LAMP: x = 0.22, p = 0.638).
LAMP assay agreed near perfectly with sWGA with non-significant differences in their ability to detect asymptomatic P. falciparum parasitaemia in blood donors. Therefore, it is recommended that LAMP based assays are employed to detect P. falciparum infections in blood donors due to its high sensitivity, simplicity, cost-effectiveness and user-friendliness.
已报道供体疟原虫寄生虫血症对储存供体血液产生不良后果。因此，使用敏感技术对所有潜在的献血者进行疟原虫感染筛查是当务之急。在这项研究中，评估了显微镜检查、快速诊断检测（RDT）、环介导等温扩增（LAMP）检测和选择性全基因组扩增（sWGA）技术在检测加纳大阿克拉地区 5 个区随机选择的献血者无症状疟原虫感染中的灵敏度。
对加纳随机选择的献血者进行无症状疟原虫感染筛查。每位献血者样本均采用 SD Bioline RDT 试剂盒检测疟原虫富含组氨酸蛋白 2 和疟原虫乳酸脱氢酶抗原、sWGA 和 18s-rRNA LAMP。粗 DNA LAMP（crDNA-LAMP）与纯化 DNA LAMP（pDNA-LAMP）进行比较。
共筛查了 771 名献血者。显微镜检查、RDT、crDNA-LAMP、pDNA-LAMP 和 sWGA 检测到加纳疟原虫的总流行率分别为 7.4%、11.8%、16.9%、17.5%和 18.0%。以 sWGA 为参考检测，显微镜检查、RDT、crDNA-LAMP 和 pDNA-LAMP 的灵敏度分别为 41.0%（95%CI 32.7-49.7）、65.5%（95%CI 56.9-73.3）、82.6%（95%CI 75.8-88.3）和 95.7%（95%CI 90.1-98.4）。LAMP 与 sWGA 之间几乎完全一致（sWGA 与 crDNA-LAMP，κ=0.87；sWGA 与 pDNA-LAMP，κ=0.96），而 crDNA-LAMP 和 pDNA-LAMP 则完全一致（κ=0.91）。拟合优度检验表明，LAMP 和 sWGA 的性能无显著差异（crDNA-LAMP 与 sWGA：x=0.71，p=0.399；pDNA-LAMP 与 sWGA：x=0.14，p=0.707）。最后，与 sWGA 相比，LAMP 在检测亚微观寄生虫血症方面的性能没有差异（sWGA 与 crDNA-LAMP：x=1.12，p=0.290；sWGA 与 pDNA-LAMP：x=0.22，p=0.638）。
LAMP 检测与 sWGA 非常吻合，在检测献血者无症状疟原虫寄生虫血症方面无显著差异。因此，建议使用基于 LAMP 的检测方法来检测献血者中的疟原虫感染，因为它具有高灵敏度、简单、具有成本效益和易于使用的特点。
