Genetic polymorphism in Taenia solium metacestodes from different Brazilian geographic areas

The aim of the present study is to investigate genetic polymorphisms in Taenia solium metacestodes from different Brazilian geographical areas and to relate them to antibody recognition in serum samples of neurocysticercosis (NC) patients. Metacestodes were obtained from the Distrito Federal (DF), Bahia, Minas Gerais (MG) and São Paulo (SP) regions of Brazil. Samples of human sera from 49 individuals with NC, 68 individuals with other helminthiasis and 40 healthy volunteers were analysed (157 individuals in total). Antigens were prepared and used in enzyme-linked immunosorbent assay and western blotting assays to detect specific immunoglobulin G antibodies. Genetic distances between metacestode populations were analysed using random amplified polymorphic DNA (RAPD) analysis. Our results show that there was a higher frequency of reactivity in the DF region in the sera from NC patients (p < 0.05), while discrimination between active and inactive NC was seen only in extracts from the MG and SP regions (p < 0.05). Using RAPD, the sample from the DF region presented a greater increase compared to the other regions. A relationship between genetic polymorphisms among T. solium metacestodes from different areas in Brazil and the differences in antibody detection in patients with NC were established

The São Vicente earthquake of 2008 April and seismicity in the continental shelf off SE Brazil: further evidence for flexural stresses

The continental margin and shelf of most stable intraplate regions tend to be relatively more seismically active than the continental interior. In the southeast continental margin of Brazil, a seismic zone extends from Rio Grande do Sul to Espirito Santo, with seismic activity occurring mainly along the continental slope and suggesting a close relationship with flexural stresses caused by the weight of the sediments. In this region, earthquakes with magnitudes larger than 5 m(b) occur every 20-25 yr, on average. The focal mechanism solutions of previous earthquakes in this zone indicated reverse faulting on planes dipping approximately 45 degrees. with horizontal P-axes. The recent 5.2 m(b) earthquake of 2008 April 23 occurred 125 km south of Sao Vicente and was well recorded by many stations in SE Brazil, as well as at teleseismic distances in North America and Africa. Its focal depth was 17 km, locating the hypocentre in the lower crust. A well-determined focal mechanism solution shows one vertical nodal plane and one subhorizontal nodal plane. The P- and T-axes exhibit large dips, which were confirmed by a regional moment tensor inversion. This unusual orientation of the fault mechanism can be attributed to a rotation of the principal stress directions in the lower crust caused by flexural effects due to the load of recent sedimentation.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ São Paulo, IAG, BR-05508090 São Paulo, BrazilState Univ São Paulo, IGCE UNESP, BR-13506900 Rio Claro, SP, BrazilTechnol Res Inst, IPT, BR-05508901 São Paulo, BrazilPetrobras SA, Rio de Janeiro, BrazilState Univ São Paulo, IGCE UNESP, BR-13506900 Rio Claro, SP, BrazilCNPq: 309724/2009-0CNPq: 30.0460/2010-

Evaluation of an enzyme immunoassay for clinical diagnosis of neurocysticercosis in symptomatic patients Avaliação de um teste imunoenzimático para o diagnóstico clínico de neurocisticercose em pacientes sintomáticos

INTRODUCTION: Neurocysticercosis is an infection of the human central nervous system caused by the metacestode larvae of Taenia solium. Neurocysticercosis is the most common parasitic disease in developing countries. Epilepsy is the most common clinical manifestation. Difficulties in confirming the diagnosis motivated the evaluation of the enzyme-linked immunosorbent assay on cerebral spinal fluid (CSF). METHODS: Twenty-two patients with NCC and 44 control patients were studied. CSF was analyzed using a commercial ELISA kit developed for NCC. Sensitivity and specificity were measured and a multivariate logistic regression was performed. RESULTS: Sensitivity and specificity of ELISA were 31.8% and 100%, respectively, with accuracy of 77.3%. Only the size of the lesions proved to be important for performance of the test. CONCLUSIONS: The results showed that ELISA contributes to the diagnosis of neurocysticercosis if the result is negative or if the patient has a lesion of 2 cm or more.<br>INTRODUÇÃO: Neurocisticercose é a infecção do sistema nervoso central causada pela larva metacestódea da Taenia solium. Neurocisticercose é a parasitose mais comum nos países em desenvolvimento. Epilepsia é a sua manifestação clínica mais comum. A dificuldade para confirmar o diagnóstico motivou a avaliação do ensaio imunoenzimático ligado à enzima no líquido cérebro-espinhal. MÉTODOS: Vinte e dois pacientes com NCC e 44 pacientes controles foram estudados. Líquido cérebro-espinhal foi analisado por um kit ELISA comercial desenvolvido para NCC. A sensibilidade e especificidade foram medidas e uma análise multivariada de regressão logística foi realizada. RESULTADOS: A sensibilidade e a especificidade de ELISA foram, respectivamente, 31,8% e 100%, com acurácia de 77,3%. Apenas o tamanho das lesões mostrou-se importante para o desempenho do teste. CONCLUSÕES: Este estudo concluiu que ELISA contribui para o diagnóstico de NCC, caso o teste seja negativo ou caso o paciente seja portador de lesão cuja dimensão seja igual ou maior que dois centímetros

Immunodiagnosis of human neurocysticercosis by using semi-purified scolex antigens from Taenia solium cysticerci Imunodiagnóstico da neurocisticercose humana usando antígenos semipurificados de escolex de cisticercos de Taenia solium

Crude antigen and semi-purified proteins from scolices of Taenia solium cysticerci were evaluated for the immunodiagnosis of human neurocysticercosis neurocysticercosis. Semi-purified proteins obtained by electrophoresis on polyacrylamide gel and by electroelution were tested by means of the immunoenzymatic reaction against sera from normal individuals and from patients with neurocysticercosis or other parasitic diseases. The 100kDa protein provided 100% sensitivity and specificity in the immunodiagnosis. When 95 or 26kDa proteins were used, 95 and 100% sensitivity and specificity were obtained, respectively. The assays involving crude antigen and sera from normal individuals or from patients with neurocysticercosis, diluted to 1:256, gave excellent agreement with those in which 100, 95 or 26kDa proteins were tested against the same serum samples diluted to 1:64. (Kappa: 0.95 to 1.00). Crude scolex antigen may be useful for serological screening, while 100, 95 or 26kDa protein can be used in confirmatory tests on neurocysticercosis-positive cases.<br>Antígeno bruto e proteínas semipurificadas de escóleces de cisticercos de Taenia solium foram avaliados para o imunodiagnóstico da neurocisticercose humana neurocisticercose. As proteínas semipurificadas, obtidas por eletroforese em gel de poliacrilamida e eletroeluição, foram testadas na reação imunoenzimática contra soros de indivíduos normais e de pacientes com neurocisticercose ou outras parasitoses. A proteína de 100kDa proporcionou 100% de sensibilidade e especificidade no imunodiagnóstico. Quando a proteína de 95 ou 26kDa foi empregada, foram obtidos 95 e 100% de sensibilidade e especificidade, respectivamente. Os ensaios envolvendo antígeno bruto e soros de indivíduos normais ou de pacientes com neurocisticercose, diluídos a 1:256, tiveram ótima concordância com aqueles onde a proteína de 100, 95 ou 25kDa foi testada contra os mesmas amostras de soro diluídas a 1:64 (Kappa: 0,95 a 1,00). O antígeno bruto de escolex poderá ser empregado na triagem sorológica enquanto a proteína de 100, 95 ou 26kDa nos testes confirmatórios dos casos positivos de NC