TF-Test Modified: New Diagnostic Tool for Human Enteroparasitosis.

Intestinal parasitosis is highly prevalent worldwide, being among the main causes of illness and death in humans. Currently, laboratory diagnosis of the intestinal parasites is accomplished through manual technical procedures, mostly developed decades ago, which justifies the development of more sensitive and practical techniques. Therefore, the main objective of this study was to develop, evaluate, and validate a new parasitological technique referred to as TF-Test Modified, in comparison to three conventional parasitological techniques: TF-Test Conventional; Rugai, Mattos & Brisola; and Helm Test/Kato-Katz. For this realization, we collected stool samples from 457 volunteers located in endemic areas of Campinas, São Paulo, Brazil, and statistically compared the techniques. Intestinal protozoa and helminths were detected qualitatively in 42.23% (193/457) of the volunteers by TF-Test Modified technique, against 36.76% (168/457) by TF-Test Conventional, 5.03% (23/457) by Helm Test/Kato-Katz, and 4.16% (19/457) by Rugai, Mattos & Brisola. Furthermore, the new technique presented "almost perfect kappa" agreement in all evaluated parameters with 95% (P < 0.05) of estimation. The current study showed that the TF-Test Modified technique can be comprehensively used in the diagnosis of intestinal protozoa and helminths, and its greater diagnostic sensitivity should help improving the quality of laboratory diagnosis, population surveys, and control of intestinal parasites.

Automatic segmentation and classification of human intestinal parasites from microscopy images.

Human intestinal parasites constitute a problem in most tropical countries, causing death or physical and mental disorders. Their diagnosis usually relies on the visual analysis of microscopy images, with error rates that may range from moderate to high. The problem has been addressed via computational image analysis, but only for a few species and images free of fecal impurities. In routine, fecal impurities are a real challenge for automatic image analysis. We have circumvented this problem by a method that can segment and classify, from bright field microscopy images with fecal impurities, the 15 most common species of protozoan cysts, helminth eggs, and larvae in Brazil. Our approach exploits ellipse matching and image foresting transform for image segmentation, multiple object descriptors and their optimum combination by genetic programming for object representation, and the optimum-path forest classifier for object recognition. The results indicate that our method is a promising approach toward the fully automation of the enteroparasitosis diagnosis.

Potential immunological markers for diagnosis and therapeutic assessment of toxocariasis.

In human toxocariasis, there are few approaches using immunological markers for diagnosis and therapeutic assessment. An immunoblot (IB) assay using excretory-secretory Toxocara canis antigen was standardized for monitoring IgG, IgE and IgA antibodies in 27 children with toxocariasis (23 visceral, three mixed visceral and ocular, and one ocular form) for 22-116 months after chemotherapy. IB sensitivity was 100% for IgG antibodies to bands of molecular weight 29-38, 48-54, 95-116, 121-162, >205 kDa, 80.8% for IgE to 29-38, 48-54, 95-121, > 205 kDa, and 65.4% for IgA to 29-38, 48-54, 81-93 kDa. Candidates for diagnostic markers should be IgG antibodies to bands of low molecular weight (29-38 and 48-54 kDa). One group of patients presented the same antibody reactivity to all bands throughout the follow-up study; in the other group, antibodies decayed partially or completely to some or all bands, but these changes were not correlated with time after chemotherapy. Candidates for monitoring patients after chemotherapy may be IgG antibodies to > 205 kDa fractions, IgA to 29-38, 48-54, 81-93 kDa and IgE to 95-121 kDa. Further identification of antigen epitopes related to these markers will allow the development of sensitive and specific immunoassays for the diagnosis and therapeutic assessment of toxocariasis.

Potential immunological markers for diagnosis and therapeutic assessment of toxocariasis / Estudo de marcadores imunológicos para o diagnóstico e avaliação terapêutica da toxocaríase

In human toxocariasis, there are few approaches using immunological markers for diagnosis and therapeutic assessment. An immunoblot (IB) assay using excretory-secretory Toxocara canis antigen was standardized for monitoring IgG, IgE and IgA antibodies in 27 children with toxocariasis (23 visceral, three mixed visceral and ocular, and one ocular form) for 22-116 months after chemotherapy. IB sensitivity was 100 percent for IgG antibodies to bands of molecular weight 29-38, 48-54, 95-116, 121-162, >205 kDa, 80.8 percent for IgE to 29-38, 48-54, 95-121, > 205 kDa, and 65.4 percent for IgA to 29-38, 48-54, 81-93 kDa. Candidates for diagnostic markers should be IgG antibodies to bands of low molecular weight (29-38 and 48-54 kDa). One group of patients presented the same antibody reactivity to all bands throughout the follow-up study; in the other group, antibodies decayed partially or completely to some or all bands, but these changes were not correlated with time after chemotherapy. Candidates for monitoring patients after chemotherapy may be IgG antibodies to > 205 kDa fractions, IgA to 29-38, 48-54, 81-93 kDa and IgE to 95-121 kDa. Further identification of antigen epitopes related to these markers will allow the development of sensitive and specific immunoassays for the diagnosis and therapeutic assessment of toxocariasis.

Métodos imunológicos desempenham papel importante no diagnóstico da toxocaríase, entretanto há poucos estudos sobre marcadores diagnósticos e de acompanhamento terapêutico. Foi padronizado ensaio de immunoblot (IB) empregando antígeno de excreção-secreção de Toxocara canis para pesquisa de anticorpos IgG, IgE e IgA em 27 crianças com toxocaríase nas formas visceral (23), mista visceral e ocular (3) e ocular (1), por 22-116 meses após quimioterapia. Foram observados dois perfis de reatividade dos anticorpos: permanência contra todas as frações no decorrer do estudo; diminuição ou negativação contra algumas ou todas as frações, porém, essas mudanças não se correlacionaram com tempo de tratamento. A sensibilidade do IB foi 100,0 por cento para anticorpos IgG específicos para frações de massa molecular de 29-38, 48-54, 95-116, 121-162, > 205 kDa, 80,8 por cento para IgE específicos para 29-38, 48-54, 95-121, > 205 kDa e 65,4 por cento para IgA específicos para 29-38, 48-54, 81-93 kDa. Anticorpos IgG específicos para frações de baixa MM (29-38 e 48-54 kDa) podem ser sugeridos como candidatos a marcadores diagnósticos. Por sua vez, anticorpos IgG para fração > 205 kDa, IgA para 29-38, 48-54, 81-93 kDa e IgE para 95-121 kDa podem ser candidatos a marcadores terapêuticos. A identificação de epítopos antigênicos relacionados a estes marcadores poderá ser importante para o desenvolvimento de ensaios altamente sensíveis e específicos no diagnóstico e avaliação terapêutica da toxocaríase.

Serodiagnosis of neurocysticercosis in patients with epileptic seizure using ELISA and immunoblot assay

Sera from 88 patients from Santa Catarina and São Paulo states of Brazil, with epileptic seizures who underwent cerebral computed tomography (CT) were analyzed for the detection of antibodies to T. solium cysticercus by ELISA and Immunoblot (IB) with the following antigens: Taenia solium cysticercus total saline (Tso), Taenia crassiceps cysticercus vesicular fluid (Tcra-vf) and T. crassiceps cysticercus glycoproteins (Tcra-gp). ELISA carried out with Tso, Tcra-vf and Tcra-gp antigens showed 95 percent, 90 percent and 80 percent sensitivities, respectively, and 68 percent, 85 percent and 93 percent specificities, respectively. In the epileptic patients group, ELISA positivity was 30 percent, 51 percent and 35 percent with Tso, Tcra-vf and Tcra-gp antigens respectively. Considering the IB as the confirmatory test, the positivity was 16 percent (14/88) in the epileptic patients total group and 22 percent (12/54) in the epileptic patients with positive CT and signals of cysticercosis. We found a significant statistical correlation among ELISA or IB results and the phase of the disease when any antigens were used (p < 0.05). We emphasize the need to introduce in the laboratory routine the search for neurocysticercosis (NC) in patients presenting with epileptic seizures because of the high risk of acquiring NC in our region and its potential cause of epilepsy.

Amostras de soro de 88 pacientes dos Estados de Santa Catarina e São Paulo, Brasil, com crises epilépticas e que se submeteram a exame de Tomografia Computadorizada (TC), foram examinadas para detecção de anticorpos anti-cisticercos de Taenia solium por meio de ELISA e Immunoblot (IB) utilizando-se os seguintes antígenos: extrato salino total de cisticercos de T. solium (Tso); líquido vesicular de Taenia crassiceps (Tcra-vf) e glicoproteínas purificadas de cisticercos de T. crassiceps (Tcra-gp). Os resultados de ELISA com os antígenos Tso, Tcra-vf e Tcra-gp mostraram 95 por cento, 90 por cento e 80 por cento de sensibilidade, respectivamente, e 68 por cento, 85 por cento e 93 por cento de especificidade, respectivamente. No grupo de pacientes epilépticos, a positividade do ELISA foi 30 por cento, 51 por cento e 35 por cento com os antígenos Tso, Tcra-vf e Tcra-gp, respectivamente. Considerando o IB como teste confirmatório, a positividade foi de 16 por cento (14/88) no grupo total de pacientes epilépticos e 22 por cento (12/54) no grupo de pacientes epilépticos com TC positiva e sinais clínicos compatíveis com neurocisticercose. Foi encontrada correlação estatística significativa entre os resultados de ELISA ou IB e a fase da doença com quaisquer dos antígenos utilizados (p < 0,05). Os resultados indicam a necessidade de introduzir na rotina dos laboratórios o diagnóstico de neurocisticercose nos pacientes com convulsões epilépticas devido ao elevado risco de aquisição da cisticercose em nossa região e sua participação na etiologia da epilepsia.

Serodiagnosis of neurocysticercosis in patients with epileptic seizure using ELISA and immunoblot assay.

Sera from 88 patients from Santa Catarina and São Paulo states of Brazil, with epileptic seizures who underwent cerebral computed tomography (CT) were analyzed for the detection of antibodies to T. solium cysticercus by ELISA and Immunoblot (IB) with the following antigens: Taenia solium cysticercus total saline (Tso), Taenia crassiceps cysticercus vesicular fluid (Tcra-vf) and T. crassiceps cysticercus glycoproteins (Tcra-gp). ELISA carried out with Tso, Tcra-vf and Tcra-gp antigens showed 95%, 90% and 80% sensitivities, respectively, and 68%, 85% and 93% specificities, respectively. In the epileptic patients group, ELISA positivity was 30%, 51% and 35% with Tso, Tcra-vf and Tcra-gp antigens respectively. Considering the IB as the confirmatory test, the positivity was 16% (14/88) in the epileptic patients total group and 22% (12/54) in the epileptic patients with positive CT and signals of cysticercosis. We found a significant statistical correlation among ELISA or IB results and the phase of the disease when any antigens were used (p < 0.05). We emphasize the need to introduce in the laboratory routine the search for neurocysticercosis (NC) in patients presenting with epileptic seizures because of the high risk of acquiring NC in our region and its potential cause of epilepsy.

Effect of cell culture system on the production of human viral antigens

Foi realizado estudo comparativo na produção de diferentes antígenos virais usando sistema de microcarregador e sistema tradicional. Células Vero, BHK e MA-104 foram cultivadas em microcarregadores (2mg/ml) utilizando-se biorreatores com capacidade de 3,7 litros e, em paralelo, no sistema convencional com garrafas Roux. Após quatro dias de cultura para as células BHK e sete dias para as células Vero e MA-104, as células foram infectadas com 0,1 MOI (multiplicidade de infecção) de vírus da raiva, vírus do sarampo, poliovírus e rotavírus. Foi determinado o rendimento das células e dos vírus em microcarregadores e sistema convencional. Foi observado no sistema de microcarregador um aumento médio obtido de vinte vezes mais células/ml em relação à cultura convencional em monocamadas, usando garrafas Roux. Por outro lado, as células que cresceram em garrafas Roux apresentaram 1,6 a 6,7 mais vírus/ml em culturas do que no sistema de microcarregador. Contudo o total das amostras em termos de vírus por grupo foi estatisticamente similar para ambos os sistemas (p > 0,05). O rendimento na produção de antígeno viral pode depender não somente da concentração das células, mas também de outros fatores da cultura, como características do suporte no crescimento. Assim, o estudo deste parâmetro pode proporcionar uma linha de base para um futuro melhoramento e estratégias para se estabelecer um aumento em escala na produção de vírus, já que, dependendo do tipo de vírus, a ótima condição encontrada para uma produção de vírus em pequena escala pode não ser adequada para a produção em grande escala, requerendo novas padronização e avaliação.

Evaluation of a novel kit (TF-Test) for the diagnosis of intestinal parasitic infections.

Intestinal parasitic infections are currently a source of concern for Public Health agencies in developing and developed countries. Since three ovum-and-parasite stool examinations have been demonstrated to provide sensitive results, we designed a practical and economical kit (TF-Test) that is now commercially available (Immunoassay Com. Ind. Ltda., São Paulo, Brazil). This kit allows the separate collection of three fecal specimens into a preservative solution. The specimens are then pooled, double-filtered, and concentrated by a single rapid centrifugation process. The TF-Test was evaluated in four different laboratories in a study using 1,102 outpatients and individuals living in an endemic area for enteroparasitosis. The overall sensitivity found using the TF-Test (86.2-97.8%) was significantly higher (P<0.01) than the sensitivity of conventional techniques such as the Coprotest (NL Comércio Exterior Ltda, São Paulo, Brazil) and the combination of Lutz/Hoffman, Faust, and Rugai techniques (De Carli, Diagnóstico Laboratorial das Parasitoses Humanas. Métodos e Técnicas, 1994), which ranged from 48.3% to 75.9%. When the above combined three specimen technique was repeated with three specimens collected on different days, its sensitivity became similar (P>0.01) to that of the TF-Test. The kappa index values of agreement for the TF-Test were consistent (P<0.01), being higher and ranking in a better position than conventional techniques. The high sensitivity, cost/benefit ratio, and practical aspects demonstrate that the TF-Test is suitable for individual diagnosis, epidemiological inquiries, or evaluation of chemotherapy in treated communities.

Implications of Haemophilus influenzae biogroup aegyptius hemagglutinins in the pathogenesis of Brazilian purpuric fever.

Brazilian purpuric fever (BPF) is an acute disease caused by Haemophilus influenzae biogroup aegyptius; it is characterized by fever, purpura, and hypotensive shock and is usually fatal. The factors responsible for bacterial virulence and pathogenesis are poorly known. Hemagglutinins have been frequently associated with bacterial virulence, and, in the present study, hemagglutinating activity was detected in extracellular products from H. influenzae biogroup aegyptius strains isolated from patients with BPF. A 60-kilodalton (kDa) molecule absorbable by human O-type erythrocytes was identified by an immunoblot assay; a corresponding fraction was chromatographically purified, and its pathogenic effect was evaluated. Rabbits injected intravenously with either the whole bacterial extracellular product or the 60-kDa fraction showed reactions similar to those seen in patients with BPF: purpura, congestion, and fibrin thrombi in the inner organs. We suggest that this hemagglutinating factor is one of the major pathogenic components of BPF.

New prevalence estimate of TT virus (TTV) infection in low- and high-risk population from São Paulo, Brazil.

The prevalence of TT virus (TTV) infection was investigated by Polymerase Chain Reaction (PCR) in low- (blood donors and healthy children/adolescents) and high-risk (hemophiliacs) groups from São Paulo, Brazil. Primers based on the untranslated region (UTR) of the viral genome proved to be much more ubiquitous, leading to much higher frequencies for both groups (>or= 81%) than the earlier N22-PCR directed to the open reading frame 1 (blood donors, 5.5%, and hemophiliacs, 42.3%). The UTR-PCR also revealed an interesting profile for healthy children/adolescents: very high prevalence at the early years and significant decrease in male teenagers. The N22-PCR, in turn, demonstrated higher frequency in hemophiliacs treated with fresh blood products (58%), than in those treated with virus-inactivated clotting factors (9.4%) and blood donors (5.5%).

New prevalence estimate of TT virus (TTV) infection in low- and high-risk population from Säo Paulo, Brazil

The prevalence of TT virus (TTV) infection was investigated by Polymerase Chain Reaction (PCR) in low- (blood donors and healthy children/adolescents) and high-risk (hemophiliacs) groups from Säo Paulo, Brazil. Primers based on the untranslated region (UTR) of the viral genome proved to be much more ubiquitous, leading to much higher frequencies for both groups ( > or = 81 percent) than the earlier N22-PCR directed to the open reading frame 1 (blood donors, 5.5 percent, and hemophiliacs, 42.3 percent). The UTR-PCR also revealed an interesting profile for healthy children/adolescents: very high prevalence at the early years and significant decrease in male teenagers. The N22-PCR, in turn, demonstrated higher frequency in hemophiliacs treated with fresh blood products (58 percent), than in those treated with virus-inactivated clotting factors (9.4 percent) and blood donors (5.5 percent)

Measles serodiagnosis: production and evaluation of the IgM-measles ELISA(IAL) reagent

Recent measles outbreaks in different countries led to an increase of laboratory measles diagnosis. Thus, we developed the IgM-Measles ELISAIAL, using measles virus antigens obtained from cell cultured in microcarriers in order to supply reagent kits to Brazilian public health laboratories. A batch of antigenic reagent was produced and evaluated in the enzyme immunoassay in comparison with clinical diagnosis and with as reference assay (IgM Capture ELISA(CDC)) data. This study was performed in a positive panel with 70 serum samples from patients with measles, and a negative panel with 132 samples from patients with unrelated diseases and without recent measles or vaccination history. In relation to other diagnostic methods, the IgM ELISAIAL presented sensitivity higher than 97.1 per cente, specificity and precision of 97 per cente, and agreement kappa (k) index higher than 0.94 (P < 0.05). Moreover, the IgM antibody profile from measles acute phase revealed by the assay was similar to the reference assay. A practical analysis system for checking the quality of new reagent batches was proposed based on the diagnostic features and agreement kappa index. Our findings suggest that measles antigenic reagents can be produced with reliable quality control system, and supplied to public health laboratories for routine serodiagnosis or population surveys.

Measles serodiagnosis: production and evaluation of the IgM-measles ELISA IAL reagent

Recent measles outbreaks in different countries led to an increase of laboratory measles diagnosis. Thus, we developed the IgM-Measles ELISA IAL, using measles virus antigens obtained from cell cultured in microcarriers in order to supply reagent kits to Brazilian public health laboratories. A batch of antigenic reagent was produced and evaluated in the enzyme immunoassay in comparison with clinical diagnosis and with as reference assay (IgM Capture ELISA CDC) data. This study was performed in a positive panel with 70 serum samples from patients with measles, and a negative panel with 132 samples from patients with unrelated diseases and without recent measles or vaccination history. In relation to other diagnostic methods, the IgM ELISA IAL presented sensitivity higher than 97.1%, specificity and precision of 97%, and agreement kappa (k) index higher than 0.94 (P 0.05). Moreover, the IgM antibody profile from measles acute phase revealed by the assay was similar to the reference assay. A practical analysis system for checking the quality of new reagent batches was proposed based on the diagnostic features and agreement kappa index. Our findings suggest that measles antigenic reagents can be produced with reliable quality control system, and supplied to public health laboratories for routine serodiagnosis or population surveys.

Recentes epidemias de sarampo em diferentes países induziram aumento de sorodiagnóstico do sarampo, inclusive em laboratórios de saúde pública brasileiros. Desta forma, desenvolvemos uma técnica de ELISA IgM IAL, utilizando antígenos de vírus do sarampo obtidos de células cultivadas em microcarregadores, com o objetivo de fornecer "kits" de reagentes para diferentes laboratórios. Foi produzida uma partida de reagente para esta técnica imunoenzimática, e os parâmetros diagnósticos foram avaliados em comparação com dados clínicos e de ensaio de referência (ELISA de captura IgM). O reagente foi estudado em um painel positivo tendo 70 soros de pacientes com sarampo e painel negativo com 132 soros de pacientes com doenças não relacionadas e sem história de sarampo recente ou vacinação. A técnica de ELISA IgM IAL demonstrou sensibilidade de 97,1% e 98,6%, especificidades de 97%, e índices kapa de concordância de 0,94 e 0,95 (p 0,05). O perfil de anticorpo IgM de sarampo da fase aguda foi também semelhante ao do ensaio de referência. Foi proposto ainda um sistema prático de análise para o controle de qualidade de reagentes com bases nos achados de validadação do reagente. Nossos achados sugerem que partidas de reagentes do vírus do sarampo podem ser produzidas sucessivamente e utilizadas em laboratórios de saúde pública para sorodiagnóstico de rotina ou inquérito soroepidemiológico de população.

Urinary tract infection: detection of Escherichia coli antigens in human urine with an ELIEDA immunoenzymatic assay / Las infecciones urinarias: detección de antígenos de Escherichia coli en orina humana con un ensayo inmunoenzimático por electrodifusión (ELIEDA)

Escherichia coli is the most common causative agent of urinary tract infection (UTI), and diagnosing this infection usually relies on bacteriologic methods. Nevertheless, screening methods can be useful for a rapid presumptive diagnosis even though some of these screening methods have low sensitivity or are expensive. To investigate a possible new alternativa approach, an antigen-based immunoassay-enzyme-linked immunoelectrodiffusion assay (ELIEDA)- was standardized for screening for this bacterial infection. Combining counter-immunoelectrophoresis with an immunoenzymatic assay, the ELIEDA requires concentrated urine specimens, a cellulose acetate membrane, polyclonal antibodies to E. coli raised in rabbits, and peroxidase-labeled sheep antibodies to rabbit immunoglobulin G (IgG). This ELIEDA technique was evaluated using 244 urine specimens, 76 of them with E.coli, 47 with heterologous bacteria, and 121 without bacteria. In comparison to bacteriologic methods, the sensitivity, specificity, and positive and negative predictive values for the ELIEDA were 93.4 por ciento, 98.2 por ciento, 95.9 por ciento, and 97.1, respectively. The data obtained suggest that this assay is useful for routine diagnostic screening for UTI caused by E.coli. In addition, since the ELIEDA stained membranes can be stored, this assay makes retrospective studies possible

Escherichia coli es el agente causal más frecuente de las infecciones urinarias (IU), cuyo diagnóstico suele basarse en métodos bacteriológicos. No obstante, los métodos de tamizaje pueden ser útiles para hacer un diagnóstico preliminar con rapidez, pese a que algunos de ellos tienen poca sensibilidad y son caros. Con el fin de investigar la posibilidad de usar otra técnica de diagnóstico, se estandarizó un inmunoensayo de tipo antigénico­ensayo inmunoenzimático por electrodifusión (ELIEDA, por e n z y m e -linked immunoelectrodiffusion assay)­para hacer el tamizaje de este tipo de infección. El ELIEDA, que consiste en el uso combinado de contrainmunoelectroforesis y un ensayo inmunoenzimático, requiere muestras de orina concentrada, una membrana celulosa con acetato, anticuerpos policlonales contra E. coli formados en conejos, y anticuerpos de cordero marcados con peroxidasa contra inmunoglobulinas G (IgG) de conejo. Esta técnica de ELIEDA se evaluó con 244 especímenes urinarios: 76 tenían E. coli; 47 tenían bacterias heterólogas y 121 carecían de bacterias. Al compararlo con los métodos bacteriológicos, el ELIEDA mostró una sensibilidad, especificidad y valores predictivos positivo y negativo de 93,4%, 95,9% y 97,1%, respectivamente. Los resultados obtenidos indican que este ensayo es útil para el tamizaje diagnóstico de rutina de las IU causadas por E. coli. Además, el ensayo facilita la realización de estudios retrospectivos, ya que las membranas teñidas usadas para el ELIEDA son almacenables

Decay of antibody isotypes against early developmental stages of Schistosoma mansoni after treatment of schistosomiasis patients

Em pacientes com esquistossomose, säo encontrados anticorpos contra grande número de antigenos parasitários, e aqueles contra formas evolutivas jovens do parasita demonstraram que eram eficientes marcadores imunológicos para o diagnóstico da esquistossomose. Padröes de queda de anticorpos IgM e IgG contra cercaria e esquistossomulo foram aqui estudados, comparativamente aos dos anticorpos contra verme e ovo, em pacientes esquistossomoticos após quimioterapia, abordando aspectos soroepidemiologicos. Dados obtidos no estudo de 359 amostras de soros, pertencentes a pacientes infectados por Schistosoma mansoni, individuos näo infectados e pacientes acompanhados pos-tratamento por um periodo de 12 a 15 meses...

Sorodiagnóstico da Doença de Chagas: novo reagente para o teste de hemaglutinaçäo indireta (THAIIAL) / Chagas' disease serological diagnosis: a new reagent to the indirect hemagglutination test (IHATIAL)

A new reagent was designed to the indirect hemagglutination test (IHATIAL), utilizing goose red blood cells as inert matrix and standardized for the field diagnosis of American trypanosomiasis. The objective was to substitute the lyophilized or frozen reagent of IHAT produced routinely using human erythrocytes in the Adolfo Lutz Institute (Säo Paulo/Brazil). The standardized reagent presented a long stability in liquid suspension, and was evaluated in 137 serum samples from patient with and without Chagas' disease, by IHATIAL. The diagnostic performance of this test was similar to the IHAT utilizing human erythrocytes and to that of a commercial IHAT kit. The sensitivity was 1.00, specificity 0.98, predictive value of positive 0.96 and of negative 1.00. Different batches of reagent successively produced proved to be reproducible in a quality control method. The new reagent is more economic than the former reagent, it can be produced easily and may be applicable to the seroepidemiologic studies.

Imunodiagnóstico da esquistossomose mansônica com baixa carga parasitária / Immunodiagnosis of schistosomiasis mansonsi with light worm burden

Presently, the schistosomiasis mansoni with low worm burden is frequent, thus immunologic assays of interest for the field diagnosis of Schistosoma mansoni light infections were evaluated here. Assays not assessed before (group I) and those requiring better validation (group II) for the screening of light infections were included in this study. In the group I, the immunofluorescence assays for the detection of IgM antibodies to worm antigens (IgM IFAw) and IgG antibodies to egg antigens (IgG IFAe) gave high levels of sensitivity, specificity, efficiency and predictive value of positive. However, the immunoenzymatic assays for the detection of IgM antibodies to worm antigens (IgM ELISAw) and to egg antigens (IgM ELISAe) had lower levels than the former assays. The assays from the group II designed mostly for the detection of IgG antibodies to same parasite antigens showed good diagnostic performance. The data obtained here contributed to evidenciate at least three category of immunoassays, and we concluded that those from the category I are suitable for seroepidemiologic purposes by keeping their diagnostic features unchanged even varying significantly the intensity of S. mansoni infection.

Schistosoma mansoni circulating polysaccharide and protein antigens recognized by sheep antisera in patients with different clinical forms of schistosomiasis before and after treatment

Dois antissoros produzidos em carneiros, um dos quais contra a fracao polissacaridica (Po) e outro contra componentes proteicos (Pt) de vermes adultos de Schistosoma mansoni, foram avaliados quanto ao seu desempenho na deteccao de antigenos parasitarios circulantes em pacientes com diferentes formas ciclicas da esquistossomose mansonica, atraves de um ensaio imunoenzimatico, (ELISA). O primeiro antissoro revelava antigenos parasitarios no granuloma hepatico e o segundo, nos glomerulos renais de pacientes com esquistossomose mansonica, bem como em camundongos experimentalmente infectados pelo S. mansoni....