Evaluation of dot-blot test for serological diagnosis of bovine brucellosis

Abstract The objective of this study was to standardize and validate the dot-blot test for the serological diagnosis of bovine brucellosis, compare the results with those found in the 2-mercaptoethanol (2-ME) and complement fixation test (CF), and estimate the relative sensitivity and specificity of the dot-blot compared to these tests. Fifty bovine blood serum samples were used for the test standardization, and 1315 samples were used for evaluation and comparison between the tests; the results were compared using the Kappa indicator. At the end of standardization, it was established as optimal for the antigen obtained from Brucella abortus B19 after passing through a microorganism rupture process, the blood serum samples diluted at 1:100, and the conjugate at 1:30,000. The comparison of the dot-blot results with 2-ME showed Kappa index of 0.9939, sensitivity of 99.48%, and specificity 99.91%, with CF, Kappa index of 0.8226, sensitivity 100% and specificity 95.32%. Using the combination of the test results 2-ME and CF to establish the true condition of the animal, the dot-blot showed relative sensitivity of 100%, and relative specificity of 99.91%. The evaluated test proved to be effective and reliable, besides being easy to handle and interpret the results.

Brucella spp. in equines slaughtered in the south region of Brazil / Anticorpos contra Brucella spp. em equídeos da região Sul do Brasil abatidos em matadouro-frigorífico

Bacteria of the genus Brucella are widespread in many countries. These microorganisms can infect humans and many wild and domestic animal species. These bacteria have zoonotic potential, and can cause economic and public health problems since they can be transmitted by direct contact with sick animals, through consumption of contaminated milk, raw meat and its derivatives (Soares et al., 2015). Brucellosis is considered a chronic evolving disease, unusual in horses, predominantly caused by Brucella abortus. However, it is not characterized by reproductive disorders in horses, but primarily by abscess in the cervical region, bursa, tendons, and joints. Transmission is likely to occur via ingestion of contaminated water and pastures, especially in areas endemic for bovine brucellosis (Ribeiro et al., 2008). The slaughterhouse is a strategic point for obtaining information about the animal and animal products, edible or not. This study investigated the presence of anti-Brucella spp. immunoglobulins in the serum samples from horses slaughtered in a slaughterhouse in southern Brazil, to estimate the frequency of Brucella spp. antibodies and determine the spatial distribution of the cases.(AU)

Objetivou-se investigar a presença de imunoglobulinas anti-Brucella spp. em amostras de soros sanguíneos de equídeos abatidos em matadouro-frigorífico, sob Serviço de Inspeção Federal, localizado na região Sul do Brasil. Utilizaram-se 767 amostras de sangue de equídeos adultos abatidos no período de abril a maio de 2013. Os animais foram provenientes de 45 municípios dos estados do Rio Grande do Sul, Santa Catarina e Paraná. Para diagnóstico, foram utilizados os testes do antígeno acidificado tamponado (AAT), sendo os resultados positivos confirmados pelos testes de polarização fluorescente (TPF), reação de fixação de complemento (RFC) e 2-mercaptoetanol (2-ME). Foram sororreagentes no AAT 65 (8,47%) animais. Destes, apenas dois (3,07%) foram positivos também na RFC e três (4,62%) animais foram positivos no TPF. Apesar da baixa frequência de animais positivos para Brucella spp., pode-se afirmar que a infecção em equinos está presente na área estudada, o que é demonstrado pela presença de animais sororreatores. No âmbito da saúde animal, pública e ocupacional, sugere-se a atenção a essa doença, visando diminuir o risco de infecção.(AU)

Outer membrane proteins and lipopolysaccharides mediated antibody response against bovine Pasteurella multocida type B-2

Aims: The activation of cellular and humoral immunity depends upon nature of antigens. Complex proteins like bacterial outer membrane proteins (OMP) usually successfully activate both humoral and cellular immunity. Whereas antigens like bacterial lipopolysaccharides (LPS) usually elicit T-independent immunity i.e. humoral immunity without the activation of cellular immune wing. The present study was under taken to evaluate the comparative immunologic behavior of both the important molecules (bacterial lipopolysaccharide and outer membrane proteins) of Pasteurella multocida alone and in combination in bovine calves in field conditions. Methodology and results: Pasteurella multocida was isolated, purified and identified from an outbreak by mean of culture and biochemical methods. The pathogenicity of the confirmed isolates was done in rabbits (Oryctolagus cuniculus) on the principles of Koch’s postulates. Alum based vaccine against P. multocida was prepared and antibody titer against Outer membrane protein (OMP) and lipopolysaccharides (LPS) were determined by complement fixation test (CFT). The results showed that the antibody titer against OMP and LPS in whole culture vaccine is significantly higher than the respective tested vaccines. These results concluded that OMP no doubt is an active T-dependent immunogenic molecule but its immunogenicity increases many times when combined with LPS in whole culture vaccine. Conclusion, significance and impact of study: Lipopolysaccharides (LPS) in combination with outer membrane proteins (OMP) synergistically boost the humoral immune response in vaccinated animal.

Human FcRn can mediate the transport across intestinal mucosal barrier and prolong the half-life of rabbit IgG in vivo

FcRn (neonatal Fc receptor) plays an important role in IgG transportation, antigen presentation and signal transmission. In this study, the complement fixation test and flow cytometry test were performed to verify whether the heterologous antibody could be transmitted to the serum or leukocyte with FcγR (Fc gamma receptor) across the intestinal mucosa. The results showed that rabbit anti-bovine IgG could be detected in both the serum and the leukocytes, which indicated that the heterologous antibody could transport across the intestinal mucosa to enter the blood and be effectively delivered to the leukocytes with FcγR. In addition, the results also showed that the rabbit anti-bovine IgG still could be detected in the leukocyte group (P=0.044<0.05) after 21 days. It indicated that the rabbit IgG could exist in the body for a long term (up to 21 days) after being transported to the cells containing FcγR.

Pharmacological Activities of a Mongolian Medicinal Plant, Malva mohileviensis Down.

Aims: To investigate the Mongolian plant M. mohileviensis Down. for the presence of possible bioactive products that could be related to the traditional use of the plant in Mongolia. Methodology: Ethanolic and water extracts of both seeds and herb were tested for antiinflammatory and DPPH scavenging activity. Polysaccharides were isolated from the seeds using sequence of chromatographic methods. The polysaccharide fraction from the cold water extract was then analyzed for the presence of monosaccharides and their type of linkages by GC and GC-MS. The effect of the polysaccharides on the complement system was then determined. Results: The ethanolic and aqueous extracts of seeds and herbs, as well as crude polysaccharides from cold and hot water extracts exhibited a significant anti-inflammatory activity in the model based on histamine-induced paw edema. Anti-inflammatory effects of all samples were high during the 3rd hour of inflammation. Moreover, the ethanolic extracts of seeds and herbs exhibited DPPH scavenging activity. Phytochemical studies of the cold water seed polysaccharide revealed the presence of an uncommon pectic type polysaccharide. Galacturonic acid (38%) and rhamnose (30%) were present as the main monosaccharides, and linkage analyses revealed that galacturonic acid was present as terminal, 14 and 13,4 linked units and rhamnose basically as 13 linked units. The complement fixation activity was appr.15 μg/ml, substantially lower than that of the standard used. The results also indicate strongly that the M. mohileviensis and M. verticillata are two different Malva species.

A comparison of two agar gel immunodiffusion methods and a complement fixation test for serologic diagnosis of Brucella ovis infection in experimentally infected rams / Comparação entre dois métodos de imunodifusão em gel de Agar e um método de fixação de complemento para o diagnóstico sorológico da infecção por Brucella ovis em carneiros experimentalmente infectados

A infecção por Brucella ovis é considerada uma das principais causas de epididimite e infertilidade em carneiros, resultando em falhas reprodutivas e perdas econômicas significativas em rebanhos ovinos ao redor do mundo. O estudo teve o objetivo de avaliar três testes sorológicos disponíveis para o diagnóstico da brucelose ovina por B. ovis, utilizando 181 soros ovinos. Amostras de soro provenientes de carneiros experimentalmente infectados foram coletadas ao longo de 192 dias pós-infecção (n=117) e durante o período pré-infecção (n=9). Adicionalmente, amostras de soro foram obtidas de ovinos provenientes de um rebanho livre para B. ovis (n=55). As técnicas de imunodifusão em gel de agar (IDGA), utilizando dois antígenos disponíveis comercialmente, e de fixação de complemento foram comparadas (FC). Foram obtidos resultados de sensibilidade especificidade semelhantes para ambos os métodos de IDGA e ainda, a técnica de IDGA foi mais eficiente do que a da FC para o diagnóstico sorológico da infecção por B. ovis.

Pesquisa de anticorpos anti-Brucella abortus e anti-Brucella ovis em ovinos no município de Uberlândia, MG / Research of Brucella abortus and Brucella ovis antibodies in sheep of Uberlândia county, MG, Brazil

The first epidemiologic inquiry to Brucella abortus (B. abortus) and Brucella ovis (B. ovis) was carried out in sheep from Uberlândia county, MG. A total of 334 blood serum samples of sheep from both sexes and different ages and breeds were collected in 12 farms. An epidemiologic questionnaire was applied for each farm. Tests for B. abortus and B. ovis antibodies were Buffered Acidified Antigen and Complement Fixation, respectively. None of the sheep was reactive to B. abortus and B. ovis; however, the adoption of sanitary measures is important to avoid the introduction of infections caused by these bacteria.

Prevalência e fatores de risco associados à infecção por Chlamydophila abortus em granjas suinícolas tecnificadas no estado de Alagoas, Brasil / Prevalence and risk factors associated with infection by Chlamydophila abortus in commercial pig farms in the state of Alagoas, Brazil

Objetivou-se com este estudo calcular a prevalência e identificar os fatores de risco associados à infecção por Chlamydophila abortus em suínos criados em granjas tecnificadas no Estado de Alagoas, Brasil. Para compor a amostra do estudo foram utilizados 342 suínos, sendo 312 matrizes e 30 varrões oriundos de sete granjas de ciclo completo e distribuídas em cinco municípios do Estado de Alagoas. O diagnóstico sorológico da infecção por C. abortus foi realizado através da microtécnica de Fixação do Complemento (RFC). A análise dos fatores de risco foi realizada por meio da aplicação de questionários investigativos, constituídos por perguntas objetivas referentes ao criador, às características gerais da propriedade, ao manejo produtivo, reprodutivo e sanitário. Observou-se prevalência de 10,5% (36/342) de suínos soropositivos para a infecção por C. abortus, com 85,8% das granjas analisadas com animais positivos. As variáveis que demonstraram associação significativa foram: utilização de bebedouros comuns para jovens e adultos (p=0,024;OR=10,83; IC=1,36–86,03) e método de cobertura de monta natural associada à inseminação artificial (p=0,05; OR=7,62; IC=1,00-58,31). Relata-se a primeira ocorrência de anticorpos anti-C. abortus em suínos no Brasil. Fatores como a introdução de reprodutores nos plantéis e a forma de fornecimento de água foram evidenciados como facilitadores da infecção das matrizes neste estudo. Dessa forma, medidas de controle da infecção devem ser enfocadas nesse aspecto para evitar a disseminação do agente nas granjas suinícolas e em outros plantéis da região.

The objective of this study was to determine the prevalence and identify risk factors associated with Chlamydophila abortus infection in commercial swine farms on the state of Alagoas, Brazil. To compose the study sample 342 pigs were used, with 312 sows and 30 boars from seven swine farms and distributed in five districts of the Alagoas. The serological diagnosis of infection by C. abortus was performed by fixation of complement microtechnique (RFC). The analysis of risk factors were performed by the application of research questionnaires, consisting of objective questions relating to the designer, the general characteristics of the property, the production, reproductive and health management. I was observed a prevalence of 10.5% (36/342) of pigs seropositive for infection by C. abortus with 85.8% of farms with positive animals analyzed. The variables that showed significant association were use of common drinker for young and adults pigs (p=0.024, OR=10.83, CI=1.36-86.03) and associated the natural mount with artificial insemination (p=0.05, OR=7.62, CI=1.00-58.31). This work reports the first occurrence of anti-C. abortusin pigs in Brazil. Factors as the introduction of boars in herds and the form of water supply were seen as facilitators of infection on sows in this study. Thus measures of infection control should be focused on this aspect to prevent the spread of the agent in pig farms and other herds in the region.

Prevalência de anticorpos contra os agentes da maedi-visna e clamidofilose em ovinos no município de Uberlândia, MG / Prevalence of antibodies against the agents of maedi-visna and chlamydophilosis in sheep from Uberlândia county, MG, Brazil

Objetivou-se com este estudo realizar o primeiro inquérito soro-epidemiológico para o vírus da maedi-visna e Chlamydophila spp. em 12 rebanhos de ovinos do Município de Uberlândia, MG. Foram utilizadas 334 amostras de soro sanguíneo de ovinos e aplicou-se um inquérito epidemiológico a cada propriedade. Os testes realizados para a pesquisa de anticorpos contra o vírus da maedi-visna e Chlamydophila spp. foram imunodifusão em gel de ágar (IDGA) e reação de fixação do complemento (RFC), respectivamente. Não foram detectados ovinos reagentes para maedi-visna. Verificou-se uma prevalência de 3,3% para Chlamydophila spp., com títulos variando de 32 a 64. Não houve diferença estatística significativa (p > 0,05) para os fatores de risco analisados. Ressalta-se a importância dos sistemas de vigilância epidemiológica para atuar no controle dessas infecções, evitando a introdução do vírus da maedi-visna e uma maior propagação da Chlamydophila spp. neste município.

The aim of this study was to carry out the first investigation into the serological prevalence of maedi-visna virus and Chlamydophila spp. on 12 sheep breeding farms in Uberlândia County, MG, Brazil. A total of 334 blood serum samples were used and an epidemiological survey was completed by each farm. The tests to detect maedi-visna and Chlamydophila spp. antibodies were an agar gel immunodiffusion (AGID) and a complement fixation test (CFT), respectively. None of the sheep were reactive to maedi-visna. The detection of antibodies against Chlamydophila spp. was 3.3%, with titers varying from 32 to 64. There was no statistically significant difference (p > 0.05) in regard to the risk factors analyzed. The importance of epidemiological surveillance systems to aid in the control of these infections is emphasized, in order to avoid the introduction of maedi-visna virus and a wider spread of Chlamydophila spp. in this county.

Ocorrência e fatores de risco para Chlamydophilaabortus em ovinos e caprinos no estado de Pernambuco: [revisão] / Occurrence and risk factors for Chlamydophilaabortus infection in sheep and goats in Pernambuco: [revision]

Objetivou-se com este estudo identificar os fatores de risco associados à infecção por Chlamydophila abortus em caprinos e ovinos nas regiões do Litoral/ Zonada Mata e Agreste do Estado de Pernambuco. Foram colhidas 290 amostras de soros para pesquisa de anticorpos contra clamídia em 12 propriedades. Para identificar os fatores de risco foram aplicados questionários junto aos proprietários. A freqüência de animais soro-reagentes nos rebanhos estudados foi de 10,3%, sendo 12,0% para caprinos e 8,1% para ovinos, identificando-se 11/12 (91,6%) focos da infecção. Registra-se a primeira ocorrência de anticorpos anti-C. abortus em caprinos no estado de Pernambuco e em ovinos no Brasil. Os fatores derisco associados à infecção em caprinos foram a raça (OR=9,10) e o manejo intensivo (OR=6,41) e para ovinosnão foram encontradas associações significativas para nenhum fator analisado. Concluiu-se que a infecção porChlamydophila sp. encontra-se disseminada em criações de caprinos e ovinos da Zona da Mata e Agreste do Estado de Pernambuco. Medidas de controle devem ser implantadas nos criatórios estudados, enfocando principalmente os fatores de risco identificados neste estudo para reduzir a possibilidade de infecção por este agente.

The study aimed to identify risk factors associated with Chlamydophila abortus infection in sheep and goats from the Litoral/Zona da Mata and Agreste region of Pernambuco state, Brazil. Serum samples (n=290) were analyzed to detect Chlamydophila spp. antibodies in 12 farms. Questionnaires were applied to identify risk factors. Frequency ofserum-reactive animals were 10.3% (12.0% in ewes and 8.1% in goats) and 1/12 (91.6%) infection focuses were identified. This is the first report on anti-Chlamydophhila abortus antibodies in goats and sheep in Pernambuco and Brazil, respectively. Risk factorsassociated with goat infection were breed (OR=9.10) and management (OR=6.41). No significant associations in any of the analyzed factors were found for sheep. In summary, Chlamydophila sp. infection is disseminated in sheep and goat herds in the region. Control measures should be established, focusing primarily risk factor identified in this study, to reduce the possibility of infection by the agent.

Recurrent Coccidioidomycosis Manifesting as Osteomyelitis in Korea / 감염과화학요법

Coccidioidomycosis is a fungal infection that results from inhaling the airborne arthroconidia of the Coccidioides species. It is an endemic disease in the southwest part of North America and rarely diagnosed in Korea. As tourism to endemic areas and the number of immunocompromised patients have been increasing, the incidence of this infection has increased in non-endemic areas. Treatment is usually successful with antifungal agents; however, recurrence is common. It is difficult to decide when to discontinue the antifungal treatment especially in non-endemic areas where doctors are not familiar with the disease. We report a case of recurrent coccidioidomycosis manifesting as osteomyelitis after the treatment of the patient for disseminated coccidioidal infection. The complement fixation test was a useful tool for the assessment of patient response and to evaluate suspected recurrence.

Recurrent Coccidioidomycosis Manifesting as Osteomyelitis in Korea / 감염과화학요법

Coccidioidomycosis is a fungal infection that results from inhaling the airborne arthroconidia of the Coccidioides species. It is an endemic disease in the southwest part of North America and rarely diagnosed in Korea. As tourism to endemic areas and the number of immunocompromised patients have been increasing, the incidence of this infection has increased in non-endemic areas. Treatment is usually successful with antifungal agents; however, recurrence is common. It is difficult to decide when to discontinue the antifungal treatment especially in non-endemic areas where doctors are not familiar with the disease. We report a case of recurrent coccidioidomycosis manifesting as osteomyelitis after the treatment of the patient for disseminated coccidioidal infection. The complement fixation test was a useful tool for the assessment of patient response and to evaluate suspected recurrence.

Prevalencia de brucelosis bovina, equina y humana en Caldas-Colombia-Sur America / Prevalence of bovine, equine and human brucellosis in Caldas-Colombia- South America

La brucelosis es considerada como una de las enfermedades infecciosas más importantes enColombia y el mundo por sus implicaciones en la salud pública, y sus repercusiones productivas en el ámbito pecuario, dejando grandes pérdidas a la economía nacional. Considerando que existe poca información sobre su prevalencia en el ámbito regional, en el transcurso de los años 2001-2002 se realizó un estudio sobre la prevalencia de la brucelosis bovina, equina y humana (personal con alto riesgo de infección) en el departamento de Caldas. Para el desarrollo del trabajo se utilizaron como pruebas diagnósticas, las técnicas rosa de Bengala y ELISA Indirecta; además se realizaron pruebas confirmatorias como ELISA competitiva y fijación de complemento para los equinos. Los resultados obtenidos en 2.434 muestras de bovinos mostraron una baja incidencia para brucelosis (0,6%), que correspondió a 15 animales hembras, distribuida en las cuatro zonas del departamento de la siguiente manera: oriente 0,24% (6 bovinos: 3 de La Dorada y 3 de la Victoria); centro-sur 0,16% (4 bovinos: 2 de Manizales, 1 de Belacázar y 1 de Villamaría); norte 0,12% (3 bovinos: 1 de Neira, 1 de Aranzazu y 1 de Salamina) y occidente 0,08% (2 bovinos, ambos en Risaralda), encontrándose animales positivos en rangos de edad de 18 a 90 meses. No se hallaron equinos reactores positivos utilizando las pruebas confirmatorias. Los resultados obtenidos en 676 muestras de humanos, arrojaron una baja prevalencia (0,14%), correspondiente a un matarife, con síntomas compatibles para brucelosis. La técnica rosa de Bengala aumentó la sensibilidad al agregar el doble de la cantidad de suero con respecto al antígeno Rosa de Bengala.

Brucellosis is considered one of the most important infectious diseases in Colombia and the world due to its implications in public health, and its productive consequences in the livestock field that is producing big losses in the economy of the country. Since there is limited information on Brucellosis in Caldas, in 2001-2002 a prevalence study on bovine, equine and human (high risk personnel) Brucellosis was carried out in the department of Caldas. For the development of the research the following diagnostic tests were used: Bengal Rose Test, indirect ELISA, as well as confirmatory tests, such as competitive ELISA and Complement Fixation, for the horses. The results obtained in 2,434 bovine samples shown a low incidence of Brucellosis (0.6%), corresponding to 15 females, distributed in the four zones of the department as follows: east zone with 0.24% (3 in La Dorada and 3 in La Victoria); central-south zone with 0.16% (2 in Manizales, 1 in Belalcazar and 1 in Villamaría); north zone with 0.12% (1 in Neira, 1 in Aranzazu and 1 in Salamina); and west zone with 0.08% (2 in Risaralda). The animals that tested positive were between 18 to 90 months of age. No equine reactors tested positive with the confirmatory test. The results obtained in 676 human samples showed a low prevalence (0.14%), corresponding to a slaugtherman with symptoms associated with Brucellosis. The Bengal Rose Test increased the sensibility when adding twice as much serum, regarding the Bengal Rose antigen.

Evaluación de la reacción en cadena de la polimerasa para el diagnóstico de la brucelosis en un rebaño lechero infectado con Brucellaspp / Assessment of polymerase chain reaction (PCR) to diagnose brucellosis in a Brucella infected herd

Para el diagnóstico de la brucelosis bovina en muestras de sangre y/o leche, se comparó la reacción en cadena de la polimerasa (PCR) con el aislamiento in vitro de Brucella abortus, las pruebas serológicas defijación del complemento (FC) e inmunoenzimáticas de competición (ELISA-C) en suero e indirecto (ELISA-I) en leche. Se analizaron muestras de vacas lecheras de un rebaño infectado “A”, vacunadas con B. abortus cepa 19 antes de los 8 meses de edad y revacunadas con B. abortus cepa RB51 como adultas (n= 99) y de otro “B”, libre de brucelosis (n=100), como control. En A, la PCR identificó 14 vacas infectadas con B. abortus: nueve con cepa silvestre y cinco con cepa silvestre y RB51. No se identificó B. abortus cepa 19. El biotipo 1 se aisló en un caso. Las 14 vacas infectadas con la cepa silvestre resultaron positivas en las tres pruebas serológicas. En B, por PCR no se identificó Brucella. Las pruebas serológicas mostraron una sensibilidad del 100% respecto de PCR. La especificidad para FC, ELISA-C y ELISA-I fue del 100%, 99% y 95%, respectivamente. Se concluye que la PCR sería útil como complemento de las pruebas serológicas o cuando no hay un resultado concluyente.

The diagnosis of bovine brucellosis using PCR in blood and milk samples from two dairy herds were compared to in vitro isolation, complement fixation test (CF), competitive ELISA (C-ELISA) in serum, and indirect ELISA (I-ELISA) in milk. Samples were obtained from 99 cows vaccinated with Brucella abortus strain 19, from a naturally infected herd (A), whose cows were also vaccinated with B. abortus strain RB51 as adults, and 100 from brucellosis free herd (B). In herd A, PCR identified 14 B. abortus infected cows: nine infected with wild type, and five with wild type and RB51, B. abortus S 19 was not identified. B. abortus biotype 1 was isolated from one cow. All cows infected with a wild strain of B. abortus were positive in serologic tests. Brucella was not found in herd B using PCR. Serological test showed 100% sensitivity related to PCR. The specificity for CF, C-ELISA and I-ELISA was 100%, 99% and 95% respectively. PCR could be useful to identify Brucella biotypes and to complement serologic tests.

Avaliação de uma nova microtécnica de fixação de complemento (Garcia & Sotelo, 1991) para o diagnóstico da doença de Chagas crônica com diferentes preparaçoes antigênicas / The evaluation of a new complement fixation microtechnic (Garcia & Sotelo, 1991) for the diagnosis of chronic Chagas disease with different antigenic preparations

No presente trabalho, avalia-se a nova fixação de complemento, comparativamente à imunofluorescência indireta, para o diagnóstico da doença de Chagas crônica, utilizando um extrato aquoso de formas epimastigotas do Trypanosoma cruzi e três extratos etanólicos: um de epimastigotas, um de tripomastigotas e outro de amastigotas obtidas de cultura. Empregaram-se 236 amostras testadas por imunofluorescência indireta: 109 positivas (20 com diagnóstico parasitológico) e 127 amostras negativas (96 de doadores de sangue e 31 de portadores de outras patologias). Os resultados mostraram que é possível obter reação positiva em amostras diluídas até 1:16. Os melhores limiares de reatividade encontrados foram a diluição 1:4 para o extrato etanólico de amastigotas e 1:2 para os demais antígenos. Os índices de correlação entre a nova fixação de complemento e imunofluorescência indireta indicaram o extrato etanólico de epimastigotas como o antígeno mais adequado para fins de diagnóstico entre as preparações testadas, tendo apresentado índice de co-positividade com a imunofluorescência indireta de 0,92207 e índice de co-negatividade de 0,90000. Conclui-se que a nova fixação de complemento mostrou-se ser uma microtécnica semi-quantitativa rápida, sensível, barata e de fácil execução, aplicável ao diagnóstico da doença de Chagas crônica.

From this present data it has been evaluated a new complement fixation test, comparatively to indirect immunofluorescence to diagnose chronic Chagas' disease, utilizing one watery extract of epimastigotes of Trypanosoma cruzi and three other ethanolic extracts: one from epimastigotes, one from tripomastigotes and a third one of amastigotes obtained from cultures. Utilizing 236 serum samples indirect immunofluorescence test was performed: 109 positives (20 of them with positive parasitologic diagnostic) and 127 negatives (96 of healthy blood donors and 31 with other diseases). The results have showed that is possible a positive reaction in diluted samples up to 1:16. The best limits of reactivity found were the dilutions 1:4 for the ethanolic extract of amastigotes and 1:2 for the others antigens. The correlation index among the new complement fixation test and indirect immunofluorescence test showed that the ethanolic extract from epimastigotes was the best antigen to be utilized to diagnosis purposes. Its co-positivity index with indirect immunofluorescence was 0.92207 and the co-negative index was 0.90000. Concluding, the new complement fixation test showed itself as a fast, sensible, easily applicable semiquantitative microtechnique to the diagnosis of chronic Chagas' disease.