Loop Mediated Isothermal Amplification (LAMP) Accurately Detects Malaria DNA from Filter Paper Blood Samples of Low Density Parasitaemias
Loop Mediated Isothermal Amplification (LAMP) Accurately Detects Malaria DNA from Filter Paper Blood Samples of Low Density Parasitaemias
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DOI：
10.1371/journal.pone.0103905
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发表时间：
2014-08-08
期刊：
影响因子：
3.7
通讯作者：
Martensson, Andreas
中科院分区：
文献类型：
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作者：
Aydin-Schmidt, Berit;Xu, Weiping;Martensson, Andreas
背景资料：环介导等温扩增（LAMP）提供了一个机会，改善，现场友好的疟疾感染的流行地区的检测。然而，缺乏关于LAMP用于主动病例检测，特别是低密度寄生虫血症的诊断准确性的数据。因此，我们评估了一个新的LAMP试剂盒的性能与PCR相比，使用DNA从滤纸blood spots.Methods和调查结果：收集在桑给巴尔的865例发热患者和465无症状的个人的样本进行了分析，泛（所有物种）和Pf（恶性疟原虫）DNA与环扩增疟疾泛/Pf试剂盒。样品在65 ℃下在实时浊度计中扩增40分钟，并将结果与巢式PCR进行比较。对LAMP和巢式PCR结果不一致的样本进行实时荧光PCR分析。将实时PCR校正的巢式PCR结果定义为金标准。在117例（13.5%）PCR检测的发热患者恶性疟原虫感染（平均虫密度7491/μ L，范围6- 782，400）中，Pan-LAMP、Pf-LAMP和巢式PCR分别为115、115和111例阳性。Pan和Pf-LAMP的灵敏度均为98.3%（95% CI 94-99.8）。在54例（11.6%）来自无症状个体的PCR阳性样本（平均寄生虫密度10/μ L，范围0-4972）中，Pf-LAMP检测41例恶性疟原虫感染的灵敏度为92.7%（95%CI 80.1-98.5）。Pan-LAMP检测恶性疟原虫和三日疟原虫的灵敏度分别为97%（95%CI 84.2-99.9）和76.9%（95%CI 46.2-95）。Pan和Pf-LAMP的特异性均为100%（95%CI 99.1-100），在两个研究groups.Conclusion：两个组件的Loopamp疟疾Pan/Pf检测试剂盒显示高诊断准确性寄生虫检测发热患者中，重要的是，也在无症状的个体中的寄生虫密度低，从分钟的血液体积保存在滤纸上。这些数据支持LAMP在消除前环境中改进低密度疟疾感染检测的潜在作用。
Background: Loop mediated isothermal amplification (LAMP) provides an opportunity for improved, field-friendly detection of malaria infections in endemic areas. However data on the diagnostic accuracy of LAMP for active case detection, particularly low-density parasitaemias, are lacking. We therefore evaluated the performance of a new LAMP kit compared with PCR using DNA from filter paper blood spots.Methods and Findings: Samples from 865 fever patients and 465 asymptomatic individuals collected in Zanzibar were analysed for Pan (all species) and Pf (P. falciparum) DNA with the Loopamp MALARIA Pan/Pf kit. Samples were amplified at 65 degrees C for 40 minutes in a real-time turbidimeter and results were compared with nested PCR. Samples with discordant results between LAMP and nested PCR were analysed with real-time PCR. The real-time PCR corrected nested PCR result was defined as gold standard. Among the 117 (13.5%) PCR detected P. falciparum infections from fever patients (mean parasite density 7491/mu L, range 6-782,400) 115, 115 and 111 were positive by Pan-LAMP, Pf-LAMP and nested PCR, respectively. The sensitivities were 98.3% (95% CI 94-99.8) for both Pan and Pf-LAMP. Among the 54 (11.6%) PCR positive samples from asymptomatic individuals (mean parasite density 10/mu L, range 0-4972) Pf-LAMP had a sensitivity of 92.7% (95%CI 80.1-98.5) for detection of the 41 P. falciparum infections. Pan-LAMP had sensitivities of 97% (95%CI 84.2-99.9) and 76.9% (95%CI 46.2-95) for detection of P. falciparum and P. malariae, respectively. The specificities for both Pan and Pf-LAMP were 100% (95% CI 99.1-100) in both study groups.Conclusion: Both components of the Loopamp MALARIA Pan/Pf detection kit revealed high diagnostic accuracy for parasite detection among fever patients and importantly also among asymptomatic individuals of low parasite densities from minute blood volumes preserved on filter paper. These data support LAMPs potential role for improved detection of low-density malaria infections in pre-elimination settings.