Detection of Schistosoma mansoni eggs in feces through their interaction with paramagnetic beads in a magnetic field.
Detection of Schistosoma mansoni eggs in feces through their interaction with paramagnetic beads in a magnetic field.
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DOI：
10.1371/journal.pntd.0000073
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发表时间：
2007-11-14
影响因子：
3.8
通讯作者：
Graeff-Teixeira C
中科院分区：
文献类型：
--
作者：
Fagundes Teixeira C;Neuhauss E;Ben R;Romanzini J;Graeff-Teixeira C
在低流行地区，肠道血吸虫病的诊断是一个问题，因为控制措施往往将粪便中的虫卵负担减少到低于传统的粪寄生虫学方法的检出限。由于缺乏具有最高灵敏度和特异性的既定标准，分子方法的评价受到阻碍。优化方法性能的一个策略是检查大量的粪便，因为鸡蛋是罕见的事件。本文报道了一种在粪便中分离曼氏血吸虫卵的新诊断方法，并对其性能进行了初步评价。将已知数量的曼氏沙门氏菌卵放入30g正常人类粪便中，进行一系列的自然沉降、筛分、里奇法、孵育和与顺磁珠相互作用的分离。初步测试证明了凝集素作为配体的功效，但他们也表明，顺磁珠本身就足以通过一种未知的机制在磁场下隔离卵子。通过显微镜检查鉴定卵子，在每克粪便（epg） 1.3个卵子时灵敏度为100%。当浓度为0.1 epg时，灵敏度逐渐下降至25%。在将新方法初步应用于巴西南部最近建立的一个疫源地的调查中，检测到的虫卵大约是厚涂片Kato-Katz方法的3倍。这种新的曼氏梭形虫检测方法可以显著提高最近寄生虫传入地区、成功控制传播地区或受感染旅行者中低负担感染的诊断。它还可以改进对新疗法和新疫苗的评估。曼氏血吸虫病是一种寄生虫感染，影响大约2亿人，主要在热带地区。这种蠕虫生活在肠道和肝脏的静脉中，产生的卵随粪便排出。如果卵进入水中，纤毛幼虫就会被释放出来，进入蜗牛体内，发育成可以感染人类和其他脊椎动物的幼虫。大多数感染发展为无明显疾病，但多年后可能出现严重的肠、肝、肺和脑-髓功能障碍。明确的诊断是通过粪便中鸡蛋的鉴定。当鸡蛋数量较低时（例如，在控制措施已降低感染强度的地区，或在仅短暂接触过的旅行者中发生轻度感染的情况下），传统诊断方法无法发现感染。本文报道了一种新的非常灵敏的方法，该方法通过与磁珠的相互作用将卵从大量粪便中分离出来。在与粪便沉淀物孵育后，卵子与珠子一起向附着在试管上的磁铁方向移动。这种诊断方法的改进将加强控制血吸虫病的努力。
Diagnosis of intestinal schistosomiasis in low endemic areas is a problem because often control measures have reduced egg burdens in feces to below the detection limits of classical coproparasitological methods. Evaluation of molecular methods is hindered by the absence of an established standard with maximum sensitivity and specificity. One strategy to optimize method performance, where eggs are rare events, is to examine large amounts of feces. A novel diagnostic method for isolation of Schistosoma mansoni eggs in feces, and an initial evaluation of its performance is reported here. Known amounts of S. mansoni eggs were seeded into 30 g of normal human feces and subjected to a sequence of spontaneous sedimentation, sieving, Ritchie method, incubation and isolation through interaction with paramagnetic beads. Preliminary tests demonstrated the efficacy of lectins as ligands, but they also indicated that the paramagnetic beads alone were sufficient to isolate the eggs under a magnetic field through an unknown mechanism. Eggs were identified by microscopic inspection, with a sensitivity of 100% at 1.3 eggs per gram of feces (epg). Sensitivity gradually decreased to 25% at a concentration of 0.1 epg. In a preliminary application of the new method to the investigation of a recently established focus in southern Brazil, approximately 3 times more eggs were detected than with the thick-smear Kato-Katz method. The novel S. mansoni detection method may significantly improve diagnosis of infections with low burdens in areas of recent introduction of the parasite, areas under successful control of transmission, or in infected travelers. It may also improve the evaluation of new treatments and vaccines. Schistosomiasis mansoni is a parasitic infection that affects approximately 200 million people, mainly in the tropics. The worms live inside the veins of intestines and liver and produce eggs that are eliminated within feces. If the eggs reach water, a ciliated larva is released and enters snails to develop into a larva infective to man and other vertebrates. Most infections evolve without overt disease, but severe intestinal, hepatic, pulmonary and cerebro-medulary dysfunctions may occur after many years. Definitive diagnosis is made through the identification of eggs in stool. Classical diagnostic methods fail to detect infection when the number of eggs is low (e.g., in areas where control measures have decreased the intensity of infection or in the case of light infections in travelers who have had only brief exposure). A new and very sensitive method is reported here, in which eggs are isolated from large amounts of feces through their interaction with magnetic beads. After incubation with the fecal sediment, eggs co-migrate with the beads towards a magnet attached to the test tube. This improvement in diagnostic methodology will strengthen efforts to control schistosomiasis.
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影响因子：
1.3
作者：
Basso, W;Venturini, L;Dubey, JP
通讯作者：
Dubey, JP
影响因子：
4.4
作者：
Kretzer, Jan W.;Lehmann, Rainer;Loessner, Martin J.
通讯作者：
Loessner, Martin J.
影响因子：
11.8
作者：
Corachan, M
通讯作者：
Corachan, M
影响因子：
2.7
作者：
Eberl, M;al-Sherbiny, M;Wilson, RA
通讯作者：
Wilson, RA
DOI：
10.1590/s0074-02762004000900013
发表时间：
2004-08-01
期刊：
Memórias do Instituto Oswaldo Cruz
影响因子：
--
作者：
Graeff-Teixeira, Carlos;Valar, Cristiana;Amaral, Ronaldo Santos do
通讯作者：
Amaral, Ronaldo Santos do