Aslan Gonul, Seyrek Adnan, Kocagoz Tanil, Ulukanligil Mustafa, Erguven Sibel, Gunalp Ayfer
University of Mersin, Faculty of Medicine, Department of Medical Microbiology, Mersin, Turkey.
Parasitol Int. 2007 Sep;56(3):217-20. doi: 10.1016/j.parint.2007.03.001. Epub 2007 Mar 12.
More than half of the world's population is exposed to malaria in approximately 100 countries. Rapid diagnosis and correct treatment of cases are the main objectives of control programs in malaria endemic areas. We have developed a PCR method to determine the presence of plasmodium DNA in blood. The method can also identify the species of the plasmodium by restriction enzyme analysis of the amplified product. We evaluated the performance of this method in the diagnosis of malaria suspected cases in Turkey by comparing to microscopy of the blood smears: blood samples were obtained from 114 patients with malaria symptoms, including fever and/or chills lasting for several days, before starting treatment. Thin and thick blood smears were prepared immediately in the region of specimen collection. After isolation of DNA from blood samples, DNA was amplified by PCR and digested by restriction enzyme AluI. The obtained fragments were analyzed by agarose gel electrophoresis. The number of parasites in the thick and thin smears of the blood samples was evaluated microscopically after staining by Giemsa and results were compared by PCR results. Among 114 plasmodium positive cases detected by microscopy, 100 were also detected by PCR. There were 14 false negatives and no false positive by PCR. Compared to microscopy, the sensitivity, specificity and Positive Predictive Value (PPV) of PCR were determined as 76%, 100% and 100%, respectively.
世界上超过一半的人口分布在约100个疟疾流行国家。对疟疾病例进行快速诊断和正确治疗是疟疾流行地区防控项目的主要目标。我们开发了一种PCR方法来检测血液中疟原虫DNA的存在。该方法还可通过对扩增产物进行限制性酶切分析来鉴定疟原虫的种类。我们通过与血液涂片显微镜检查结果进行比较，评估了该方法在土耳其疟疾疑似病例诊断中的性能：在开始治疗前，从114名有疟疾症状（包括持续数天的发热和/或寒战）的患者身上采集血样。在标本采集区域立即制备薄血膜和厚血膜。从血样中分离出DNA后，通过PCR进行扩增，并用限制性酶AluI进行消化。通过琼脂糖凝胶电泳分析得到的片段。对血样的薄血膜和厚血膜经吉姆萨染色后进行显微镜检查，评估疟原虫数量，并将结果与PCR结果进行比较。在显微镜检查检测出的114例疟原虫阳性病例中，有100例也被PCR检测出来。PCR检测有14例假阴性，无假阳性。与显微镜检查相比，PCR的灵敏度、特异性和阳性预测值（PPV）分别确定为76%、100%和100%。
