Koffi M, Solano P, Denizot M, Courtin D, Garcia A, Lejon V, Büscher P, Cuny G, Jamonneau V
Institut de Recherche Pour le Développement, Unité de Recherche 177, Programme Santé Animale, TA 207/G, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France.
Acta Trop. 2006 May;98(2):183-8. doi: 10.1016/j.actatropica.2006.04.001. Epub 2006 May 24.
The serological and parasitological tests used for Trypanosoma brucei gambiense human African trypanosomiasis (HAT) diagnosis have low specificity and sensitivity, respectively, and in the field, control program teams are faced with subjects with positive serology but negative parasitology who remain untreated. The aim of this work was to explore, using PCR tool, the significance of these aparasitemic serological suspects. Since discordant PCR results have been observed earlier with different extraction methods, two DNA extraction methods were compared (the Chelex 100 resin and the DNeasy Tissue kit). The study was conducted on 604 blood samples: 574 from parasitologically confirmed patients, aparasitemic serological suspects and endemic controls collected in Côte d'Ivoire and 30 from healthy volunteers collected in France. No significant differences were observed between the PCR results obtained with the two extraction methods. Concerning PCR, problems of reproducibility and discordances with both serological and parasitological test results were observed, mainly for the aparasitemic serological suspects. In addition to previous results that pointed to the existence of non-virulent or non-pathogenic trypanosome strains and of individual susceptibility leading to long term seropositivity without detectable parasitaemia but positive PCR, the results of this study support the notion of a long lasting human reservoir that may contribute to the maintenance or periodic resurgences of HAT in endemic foci.
用于布氏冈比亚锥虫引起的人类非洲锥虫病（HAT）诊断的血清学和寄生虫学检测的特异性和敏感性分别较低，在实地，防控项目团队面临着血清学呈阳性但寄生虫学检测呈阴性的未接受治疗的受试者。这项工作的目的是使用PCR工具探究这些无寄生虫血症的血清学疑似病例的意义。由于之前观察到不同提取方法的PCR结果不一致，因此比较了两种DNA提取方法（螯合树脂100和DNeasy组织试剂盒）。该研究对604份血样进行了检测：574份来自在科特迪瓦收集的经寄生虫学确诊的患者、无寄生虫血症的血清学疑似病例和地方性对照，30份来自在法国收集的健康志愿者。两种提取方法获得的PCR结果之间未观察到显著差异。关于PCR，观察到了可重复性问题以及与血清学和寄生虫学检测结果的不一致性，主要出现在无寄生虫血症的血清学疑似病例中。除了之前指出存在无毒力或无致病性的锥虫菌株以及个体易感性导致长期血清学阳性但无可检测到的寄生虫血症但PCR呈阳性的结果外，本研究结果支持了存在长期人类储存宿主的观点，这可能有助于维持或周期性再现地方性病灶中的HAT。
