Nadeem Muhammad Faisal, Khattak Aamer Ali, Zeeshan Nadia, Awan Usman Ayub, Yaqoob Adnan
Department of Biochemistry, University of Gujrat, Gujrat, Punjab, Pakistan.
Department of Medical Laboratory Technology, The University of Haripur, Haripur, Khyber Pakhtunkhwa, Pakistan.
Acta Parasitol. 2021 Dec;66(4):1186-1192. doi: 10.1007/s11686-021-00374-8. Epub 2021 Apr 11.
Diagnostic accuracy of malaria is critical for early treatment, control, and elimination of malaria, especially in war-affected malaria-endemic areas. Microscopic detection of Plasmodium species has been the gold standard in remote malaria-endemic regions. However, the diagnostic accuracy is still questioned, especially in discriminating mixed and submicroscopic parasitic levels. This study was designed to evaluate the diagnostic performance of microscopic examination against nested PCR analysis in war-torn malaria-endemic Federally Administered Tribal Areas (FATA) of Pakistan.
Venous blood samples were collected from symptomatic patients for microscopic examination and nested PCR analysis from January 2016-December 2016 from five Agencies (Bajaur, Mohmand, Khyber, Orakzai and Kurram Agency) and four Frontier Regions (Peshawar, Kohat, Bannu, and Dera Ismail Khan Frontier Region) of FATA. Malaria-positive isolates were confirmed by nested PCR (targeting Plasmodium small subunit ribosomal ribonucleic acid (ssrRNA) genes) for speciation.
Among enrolled participants, 762 were found positive for malaria parasite on microscopic examination of the blood film. Plasmodium vivax was found in 623, Plasmodium falciparum in 132 and 7 were diagnosed with mixed infection (P. vivax and P. falciparum coinfection). Nested PCR detected Plasmodium infection in 679 samples (523 P. vivax, 121 P. falciparum, and 35 mixed infections). Compared with microscopy, the sensitivity of nested PCR was 98.94%, and specificity was 98.27%, while the sensitivity and specificity of slide microscopy 89.34% and 87.99% respectively.
The conventional microscopy method has low sensitivity to detect the mixed infection as compared to nested PCR. High sensitivity and specificity observed in nested PCR make this molecular tool a useful technique for monitoring, controlling, and eliminating malaria-endemic regions.
疟疾的诊断准确性对于疟疾的早期治疗、控制和消除至关重要，尤其是在受战争影响的疟疾流行地区。在偏远的疟疾流行地区，疟原虫种类的显微镜检测一直是金标准。然而，其诊断准确性仍受到质疑，尤其是在区分混合感染和亚显微寄生虫水平方面。本研究旨在评估在巴基斯坦饱受战争蹂躏的疟疾流行联邦直辖部落地区（FATA），显微镜检查相对于巢式PCR分析的诊断性能。
2016年1月至2016年12月，从有症状的患者中采集静脉血样本，用于显微镜检查和巢式PCR分析，这些患者来自FATA的五个机构（巴焦尔、莫赫曼德、开伯尔、奥拉卡兹和库拉姆机构）和四个边境地区（白沙瓦、科哈特、班努和德拉伊斯梅尔汗边境地区）。通过巢式PCR（靶向疟原虫小亚基核糖体核糖核酸（ssrRNA）基因）对疟疾阳性分离株进行确诊和物种鉴定。
在登记的参与者中，762人在血涂片显微镜检查中被发现疟原虫呈阳性。其中间日疟原虫623例，恶性疟原虫132例，7例被诊断为混合感染（间日疟原虫和恶性疟原虫合并感染）。巢式PCR在679份样本中检测到疟原虫感染（523例间日疟原虫，121例恶性疟原虫，35例混合感染）。与显微镜检查相比，巢式PCR的敏感性为98.94%，特异性为98.27%，而涂片显微镜检查的敏感性和特异性分别为89.34%和87.99%。
与巢式PCR相比，传统显微镜检查方法检测混合感染的敏感性较低。巢式PCR所观察到的高敏感性和特异性使其成为监测、控制和消除疟疾流行地区的有用技术。
