Palacios X, Belli A, Espino A M
Centro Nacional de Diagnóstico y Referencia, Managua, Nicaragua.
Rev Panam Salud Publica. 2000 Dec;8(6):411-7. doi: 10.1590/s1020-49892000001100006.
We standardized a solid-phase enzyme-linked immunosorbent assay (ELISA) in order to study the presence of Trypanosoma cruzi antibodies in asymptomatic persons who live in an area of Nicaragua endemic for Chagas' disease. The test was standardized to analyze filter-paper blood samples, which are easy to transport. In the first phase of our investigation, ELISA was used to study 18 samples of total serum and 18 eluates of blood from patients with chronic Chagas' disease; 30 samples of serum and 30 eluates of blood from healthy people, used as negative controls; and 14 samples of serum and 14 eluates of blood from patients with cutaneous or visceral leishmaniasis, which were used to study cross-reactions. Both with the total-serum and the blood-eluate samples, the ELISA test provided 100% sensitivity and 90% specificity. Cross-reactions in the patient samples were observed only with visceral leishmaniasis. The second phase of our investigation was a population study that included eight rural communities in the area of Somoto, Nicaragua. Through random sampling, filter-paper blood samples were collected from 2,434 people (1,335 men and 1,099 women) from the communities of Aguas Calientes, El Brocal, La Manzana, Las Playas, Los Canales, Santa Isabel, Santa Rosa, and Santa Teresa. Studied by ELISA and by indirect immunofluorescence (IIF), the samples included 260 found seropositive by ELISA (10.7%), of which 207 were positive according to IIF (8.5%). With both techniques, the majority of seropositives were among women, but the difference between men and women was not statistically significant. There was a high level of agreement between the results obtained with the two techniques. There was an upward trend with age, with 5.4% of those found seropositive by ELISA being persons 10 years of age or younger and 42.7% of those found seropositive being older than 50. The vast majority of the individuals analyzed were asymptomatic.
我们标准化了一种固相酶联免疫吸附测定法（ELISA），以研究生活在尼加拉瓜恰加斯病流行地区的无症状人群中克氏锥虫抗体的存在情况。该检测方法经过标准化处理，用于分析易于运输的滤纸血样。在我们调查的第一阶段，ELISA用于研究18份慢性恰加斯病患者的全血清样本和18份血液洗脱液；30份健康人的血清样本和30份血液洗脱液，用作阴性对照；以及14份皮肤或内脏利什曼病患者的血清样本和14份血液洗脱液，用于研究交叉反应。无论是全血清样本还是血液洗脱液样本，ELISA检测的灵敏度均为100%，特异性为90%。仅在内脏利什曼病患者样本中观察到交叉反应。我们调查的第二阶段是一项人群研究，涵盖了尼加拉瓜索莫托地区的八个农村社区。通过随机抽样，从阿瓜斯卡连特斯、埃尔布罗卡尔、拉曼萨纳、拉斯普拉亚斯、洛斯卡纳莱斯、圣伊莎贝尔、圣罗莎和圣特雷莎等社区的2434人（1335名男性和1099名女性）中采集了滤纸血样。通过ELISA和间接免疫荧光法（IIF）进行检测，样本中有260份经ELISA检测为血清阳性（10.7%），其中207份经IIF检测为阳性（8.5%）。两种技术检测结果显示，大多数血清阳性者为女性，但男女之间的差异无统计学意义。两种技术获得的结果之间具有高度一致性。随着年龄增长呈上升趋势，ELISA检测为血清阳性者中10岁及以下的占5.4%，50岁以上的占42.7%。绝大多数接受分析的个体无症状。
