Beurskens Martijn, Mens Pètra, Schallig Henk, Syafruddin Din, Asih Puji Budi Setia, Hermsen Rob, Sauerwein Robert
Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Am J Trop Med Hyg. 2009 Aug;81(2):366-9.
Microscopic detection of Plasmodium vivax gametocytes, the sexual life stage of this malaria parasite, is insensitive because P. vivax parasitaemia is low. To detect and quantify gametocytes a more sensitive, quantitative real-time Pvs25-QT-NASBA based on Pvs25 mRNA was developed and tested in two clinical sample sets from three different continents. Pvs25-QT-NASBA is highly reproducible with low inter-assay variation and reaches sensitivity approximately 800 times higher than conventional microscopic gametocyte detection. Specificity was tested in 104 samples from P. vivax-, P. falciparum-, P. malariae-, and P. ovale-infected patients. All non-vivax samples were negative in the Pvs25-QT-NASBA; out of 74 PvS18-QT-NASBA positive samples 69% were positive in the Pvs25-QT-NASBA. In a second set of 136 P. vivax microscopically confirmed samples, gametocyte prevalence was 8%, whereas in contrast 66% were positive by Pvs25-QT-NASBA. The data suggest that the human P. vivax gametocyte reservoir is much larger when assessed by Pvs25-QT-NASBA than by microscopy.
间日疟原虫配子体（该疟原虫的有性生殖阶段）的显微镜检测并不灵敏，因为间日疟原虫血症水平较低。为了检测和定量配子体，开发了一种基于Pvs25 mRNA的更灵敏的定量实时Pvs25-QT-NASBA，并在来自三大洲的两个临床样本组中进行了测试。Pvs25-QT-NASBA具有高度可重复性，测定间变异低，灵敏度比传统显微镜配子体检测高出约800倍。在来自间日疟原虫、恶性疟原虫、三日疟原虫和卵形疟原虫感染患者的104份样本中测试了特异性。所有非间日疟原虫样本在Pvs25-QT-NASBA检测中均为阴性；在74份PvS18-QT-NASBA阳性样本中，69%在Pvs25-QT-NASBA检测中呈阳性。在第二组136份经显微镜确认的间日疟原虫样本中，配子体流行率为8%，而相比之下，Pvs25-QT-NASBA检测的阳性率为66%。数据表明，通过Pvs25-QT-NASBA评估时，人类中间日疟原虫配子体库比显微镜检测时要大得多。
