RESUMO
In regions where Chagas disease is endemic, canine Trypanosoma cruzi infection is highly correlated with the risk of transmission of the parasite to humans. Herein we evaluated the novel TcTASV protein family (subfamilies A, B, C), differentially expressed in bloodstream trypomastigotes, for the detection of naturally infected dogs. A gene of each TcTASV subfamily was cloned and expressed. Indirect enzyme-linked immunosorbent assays (ELISA) were developed using recombinant antigens individually or mixed together. Our results showed that dogs with active T. cruzi infection differentially reacted against the TcTASV-C subfamily. The use of both TcTASV-C plus TcTASV-A proteins (Mix A+C-ELISA) enhanced the reactivity of sera from dogs with active infection, detecting 94% of the evaluated samples. These findings agree with our previous observations, where the infected animals exhibited a quick anti-TcTASV-C antibody response, coincident with the beginning of parasitaemia, in a murine model of the disease. Results obtained in the present work prove that the Mix A+C-ELISA is a specific, simple and cheap technique to be applied in endemic areas in screening studies. The Mix A+C-ELISA could help to differentially detect canine hosts with active infection and therefore with high impact in the risk of transmission to humans.
Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/genética , Antígenos de Protozoários/isolamento & purificação , Doença de Chagas/diagnóstico , Doença de Chagas/veterinária , Doenças do Cão/diagnóstico , Trypanosoma cruzi/imunologia , Animais , Antígenos de Protozoários/imunologia , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia , Cães , Ensaio de Imunoadsorção Enzimática/economia , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/veterinária , Camundongos , Sensibilidade e EspecificidadeRESUMO
Dogs are considered the main mammal reservoir of Trypanosoma cruzi in domiciliary environments. Consequently, accurate detection of T. cruzi infection in canine populations is epidemiologically relevant. Here, we analysed the utility of the T. cruzi recombinant antigens FRA, SAPA, CP1, Ag1 and a SAPA/TSSA VI mixture, in an ELISA format. We used a positive control group of sera obtained from 38 dogs from the Chaco region in Argentina with positive homogenate-ELISA reaction, all of them also positive by xenodiagnosis and/or PCR. The negative group included 19 dogs from a nonendemic area. Sensitivity, specificity, area under the curve (AUC) of the receiver operating charactheristic (ROC) curve and Kappa index were obtained to compare the diagnostic efficiency of the tests. The SAPA/TSSA VI had the highest performance, with a sensitivity of 94.7% and an AUC ROC of 0.99 that indicates high accuracy. Among individual antigens, SAPA-ELISA yielded the highest sensitivity (86.8%) and AUC ROC (0.96), whereas FRA-ELISA was the least efficient test (sensitivity = 36.8%; AUC ROC = 0.53). Our results showed that the use of SAPA/TSSA VI in ELISAs could be a useful tool to study dogs naturally infected with T. cruzi in endemic areas.
Assuntos
Antígenos de Protozoários/análise , Antígenos/análise , Doença de Chagas/veterinária , Doenças do Cão/diagnóstico , Animais , Antígenos/genética , Antígenos de Protozoários/genética , Argentina , Doença de Chagas/diagnóstico , Cães , Ensaio de Imunoadsorção Enzimática/veterinária , Proteínas Recombinantes/análise , Proteínas Recombinantes/genética , Sensibilidade e Especificidade , Trypanosoma cruzi/imunologiaRESUMO
A total of 221 children from two rural settlements in Northeast Argentina were examined for T. cruzi infection. Blood samples were taken for serology tests and PCR assays. In addition, T. cruzi Discrete Typing Units (DTUs) were determined by hybridization with specific DNA probes of the minicircle hypervariable regions (mHVR). Serological results indicated that 26% (57/215) were reactive against T. cruzi antigens. PCR analyses were performed on seropositive samples showing presence of parasite DNA in 31 out of 53 samples (58.5%). All seropositive children underwent specific chemotherapy with Benznidazole (5mg/kg/day) for a period of two months and were monitored two and five years after treatment. Overall the treatment was well tolerated and low side effects were observed. Serological conversion was observed at two years post -treatment in one child form Pampa Ávila and at five years in two children from Tres Estacas. However, at the end of the follow-up period, T. cruzi DNA could not be detected by PCR in samples from treated children, except in two cases. In addition, the results of hybridizations with specific DNA probes showed that DTU TcV was detected in 68% (21/31), TcVI in 7% (2/31) and TcV/VI in 3% (1/31) of the samples. Altogether, results of the follow-up of treated children showed a low rate of seroconversion; however trend toward seroconversion was evident at five years post-treatment. On the other hand, detection of T. cruzi DNA by PCR significantly decreased after Benznidazole treatment. The existence of data regarding serological and molecular follow-ups from controlled studies in the Chaco Region will be important for future treatment efforts against T. cruzi infection in this region. The results obtained in the present study represent a contribution in this regard.
Assuntos
Antiprotozoários/uso terapêutico , Doença de Chagas/tratamento farmacológico , Nitroimidazóis/uso terapêutico , Trypanosoma cruzi/isolamento & purificação , Adolescente , Anticorpos Antiprotozoários/sangue , Argentina , Criança , Pré-Escolar , Doença Crônica , DNA de Cinetoplasto , DNA de Protozoário/genética , Feminino , Seguimentos , Genótipo , Humanos , Masculino , Hibridização de Ácido Nucleico , População Rural , Resultado do Tratamento , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genéticaRESUMO
The rTSSA-II (recombinant Trypomastigote Small Surface II) antigen was evaluated by ELISA to detect anti-Trypanosoma cruzi antibodies in sera from naturally infected dogs and humans. For this evaluation ELISA-rTSSA-II was standardized and groups were classified according to the results obtained through xenodiagnosis, ELISA and PCR. Sensitivity (Se), Specificity (Sp), Kappa index (KI) and area under curve (AUC) were determined. The Se was determined by using 14 sera from dogs infected with T. cruzi VI (TcVI) whereas Sp was determined by using 95 non-chagasic sera by xenodiagnosis, ELISA-Homogenate and PCR. The performance of ELISA-rTSSA-II in dog sera was high (AUC=0·93 and KI=0·91). The Se was 92·85% (1 false negative) and Sp was 100%. Two sera from dogs infected with TcI and 1 with TcIII were negative. For patients infected with T. cruzi, reactivity was 87·8% (36/41), there was only 1 indeterminate, and Sp was 100%. Fifty-four sera from non-chagasic and 68 sera from patients with cutaneous leishmaniasis did not react with rTSS-II. ELISA-rTSSA-II showed a high performance when studying sera from naturally infected dogs and it also presented 100% Sp. This assay could be an important tool to carry out sero-epidemiological surveys on the prevalence of T. cruzi circulating lineages in the region.
Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários , Doença de Chagas/diagnóstico , Doenças do Cão/diagnóstico , Trypanosoma cruzi/imunologia , Animais , Antígenos de Protozoários/imunologia , Antígenos de Protozoários/isolamento & purificação , Antígenos de Superfície/imunologia , Antígenos de Superfície/isolamento & purificação , Argentina/epidemiologia , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia , Cães , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/veterinária , Humanos , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , Sensibilidade e Especificidade , Estudos SoroepidemiológicosRESUMO
Data on the prevalence of Trypanosoma cruzi infection is presented for the province of Salta, Argentina. Special emphasis is given to the detection of congenital transmission and to the economic benefits of preventing Chagas' disease. Seroepidemiological data obtained from 20 year old army draftees revealed a reduction, from 22.7 to 11.11% between 1964 and 1985. In university students, a rate of 0.96% was found in 1998. Surveys carried out during 1996 showed that more than 15% of the pregnant women analyzed carried T. cruzi infection, particularly in the north of the province. This situation brings about a high risk of appearance of congenital cases and represents an opportunity to test the most adequate strategies for detection. By applying systematically microhematocrit, hemoculture and PCR methods, to umbilical chord blood, an increase in the early detection of congenitally infected babies is being achieved. In 1992-94, very high seroprevalence rates of infection were found among indians of the Chaco region of Salta. The overall rate was 37%, but there were 5 localities where more than 54% of the population was infected. These numbers indicate that, in vast areas of the provincial territory, fight against vector bugs must not merely consist of surveilance activities, but rather of renewed spraying attacks. The fight must include control of pregnant women and blood banks. An economic analysis of the economic return, calculated only for spraying activities and for the Department of Anta (Salta), indicated a net present value of over 7 million dollars and an internal rate of return exceeding 60%.
Assuntos
Doença de Chagas/transmissão , Argentina/epidemiologia , Doença de Chagas/congênito , Doença de Chagas/epidemiologia , Criança , Análise Custo-Benefício , Feminino , Humanos , Incidência , Lactente , Insetos Vetores , Gravidez , Fatores de Risco , Estudos SoroepidemiológicosRESUMO
The authors present the preliminary results of 20 patients selected to be operated on between January 1996 and April 1997. These patients presented one of the present indications for stereotactic posteroventral pallidotomy (PVP), such as: rigidity, akinesia/bradykinesia, gait dysfunction, drug induced dyskinesias and tremor. Every patient of this protocol was evaluated by: UPDRS score, Schwab and England scale, Hoehn and Yahr Staging Scale before and after surgery. The results in 3 months showed a remarkable improvement after PVP (P < 0.01) in all functional assessments, except for facial expression, speech and posture. The morbidity was 5%. 5 patients (25%) who were in Hoehn and Yahr 5 underwent a bilateral simultaneous PVP. In 5 patients (25%), who had tremor, during the PVP, VIM thalamotomy was added. These preliminary results, suggest that PVP is highly effective for PD symptoms.
Assuntos
Globo Pálido/cirurgia , Doença de Parkinson/cirurgia , Tálamo/cirurgia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas Estereotáxicas , Resultado do TratamentoRESUMO
In a series of 44 image guided stereotactic biopsy from August 1995 until March 1997, findings were as follows (frequency order). Tumors, glioblastoma was the most frequent. Primary lymphoma and other conditions associated to AIDS. Metastasis, three cases, Vasculites, two cases, Arachnoid cyst, Creutzfeldt-Jakob, cortical degeneration, inespecific calcification (one case each). The age varied from 1 to 83 years. Forty one lesions were supratentorial, two infratentorial, and one was outside the brain (dura and skull) and we used stereotaxy to localize it. There was no mortality and morbidity was 2.3%. The literature is reviewed. We conclude that this procedure is safe and highly diagnostic.
Assuntos
Sistema Nervoso Central/patologia , Técnicas Estereotáxicas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios XRESUMO
Prospective series showing the importance of computerized stereotactic brain biopsy in the management of AIDS patients neurologically symptomatic and confirmed by images. Patients undergone an algorithm step by step done by their own doctors and referred to us for stereotactic biopsy. Our protocol was opened in August 1995 and closed in December 1996. Twenty patients were biopsied. This protocol is similar to the Levy's one (Chicago IL, USA). We have got diagnosis in all cases. Lymphoma was predominant and followed by toxoplasmosis, progressive multifocal leukoencephalopathy and HIV encephalopathy. We included one patient with diploic giant cells lymphoma. Our mortality and morbidity was zero. By these results we conclude that stereotactic biopsy in AIDS patients is safe and effective.
Assuntos
Complexo AIDS Demência/patologia , Síndrome da Imunodeficiência Adquirida/patologia , Leucoencefalopatia Multifocal Progressiva/patologia , Linfoma/patologia , Técnicas Estereotáxicas , Toxoplasmose Cerebral/patologia , Adulto , Biópsia , Humanos , Linfoma Relacionado a AIDS/patologia , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Estudos Prospectivos , Tomografia Computadorizada por Raios XRESUMO
The protective effect of experimental immunization was studied in guinea pigs exposed to vectorial infection by Trypanosoma cruzi. Immunized animals received an inoculum of live-attenuated T. cruzi epimastigotes into a granuloma previously induced by Freund's complete adjuvant in the hind footpad. Seven days later, a delayed-type hypersensitivity reaction was triggered by reinjection of the parasites in the front footpad. The animals were then placed in Triatoma infestans-colonized corrals and exposed to vectorial T. cruzi transmission of the parasite for up to 200 days. The effectiveness of this immunizing protocol was controlled in terms of the number of bites necessary for infection (NBNI) in immunized as compared with control animals. Periodic entomological census allowed for the determination of vector biting and infection rates and the calculation of NBNI. Although this measurement was quite variable between yards, an overall average of 4,973 bites was enough to infect a control guinea pig in 4 separate experiments. The corresponding figure for the experimental group was 21,307 bites, implying that immunized animals could resist a 4.28-fold increase (range: 1.99-8.32) in the number of vector bites before becoming infected.
Assuntos
Doença de Chagas/prevenção & controle , Insetos Vetores/imunologia , Vacinas Protozoárias/imunologia , Triatoma/imunologia , Trypanosoma cruzi/imunologia , Animais , Doença de Chagas/imunologia , Doença de Chagas/parasitologia , Cobaias , Imunidade Inata , Distribuição Aleatória , Fatores de Risco , Vacinas Atenuadas/imunologiaRESUMO
The humoral and cellular immune responses induced by the recombinant SAPA (shed acute phase antigen) of Trypanosoma cruzi were studied in mice and correlated with the immunologic control of parasitemia. The immunizing schedule used consisted of 2 weekly injections of 50 micrograms glutathione-S-transferase (GST)-SAPA in Freund's adjuvant. Specific alpha GST-SAPA antibodies were detected by enzyme-linked immunosorbent assay 1 wk after each antigen dose, the concentration of antibodies after the second injection being 30-fold higher than after the first. Immediate- (ITH) and delayed-type hypersensitivity (DTH) reactions were observed as footpad swelling after injecting 50 micrograms GST-SAPA in preimmunized mice as compared to naive controls. Adoptive transfer experiments indicated that these cutaneous reactions were mediated by lymphoid cells and not by serum. Both humoral and cellular responses were specific for the GST-SAPA antigen and did not cross-react with either the GST or the recombinant GST-1 T. cruzi antigen. Immunized mice that had developed high levels of antibody and DTH reaction to GST-SAPA were able to control the level of parasitemia after challenge with 10(3) blood trypomastigotes. The levels of parasitemia obtained were lowered to about 1/3 (P < 0.05) and mortality at day 60 was reduced from 67 to 25% (P = 0.085). Comparison of this immunizing method with other schedules involving more injections or higher antigen doses indicates that control of parasitemia can be obtained with low amounts of antigen and seems to be associated with the development of DTH.
Assuntos
Antígenos de Protozoários/imunologia , Doença de Chagas/prevenção & controle , Glicoproteínas/imunologia , Neuraminidase/imunologia , Trypanosoma cruzi/imunologia , Vacinação , Animais , Anticorpos Antiprotozoários/sangue , Feminino , Hipersensibilidade Tardia , Hipersensibilidade Imediata , Masculino , Camundongos , Parasitemia/prevenção & controle , Proteínas Recombinantes/imunologia , Reprodutibilidade dos Testes , Vacinação/métodosRESUMO
Experimental systems to assay immunity against Trypanosoma cruzi usually demonstrate partial resistance without excluding the establishment of sub-patent infections in protected animals. To test whether Swiss mice immunized with attenuated parasites might develop complete resistance against virulent T. cruzi, experiments were performed involving challenge with low numbers of parasites, enhancement of local inflammation and the combination of natural and acquired resistance. Absence of infection was established after repeated negative parasitological tests (including xenodiagnosis and hemoculture), and lack of lytic antibody was tested by complement mediated lysis. Immunization with 10(7) attenuated epimastigotes conferred protection against the development of high levels of parasitemia after challenge with Tulahuen strain, but was unable to reduce the number of infected animals. However, when a strong, delayed-type hypersensitivity reaction was triggered at the site of infection by injecting a mixture of virulent and attenuated T. cruzi, a significant proportion of immunized animals remained totally free of virulent infection. The same result was obtained when the immunization experiment was performed in four month old Swiss mice, displaying a relatively high natural resistance and challenged with wild, vector-borne parasites. These experiments demonstrate that complete resistance against T. cruzi can be obtained in a significant proportion of animals, under conditions which replicate natural, vector delivered infection by the parasite.
Assuntos
Doença de Chagas/imunologia , Imunização/métodos , Trypanosoma cruzi/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Doença de Chagas/parasitologia , Doença de Chagas/prevenção & controle , Proteínas do Sistema Complemento/imunologia , Feminino , Hipersensibilidade Tardia , Masculino , CamundongosRESUMO
Cerebrospinal fluid (CSF) changes in brain cysticercosis have long been known. Its characteristic features are a mild or moderate pleocytosis with eosinophils, a slight or moderate protein increase with an elevated gammaglobulin concentration, and a positive complement fixation test. Unfortunately all these abnormalities are not always present together and difficulties may be encountered in the diagnosis. This paper presents a study based on the experience acquired in the CSF Laboratory of the Neurological Department of Escola Paulista de Medicina (São Paulo, Brasil) after 35 years' work, and 120.000 CSF specimens examined. The material consists of 147 cases of brain cysticercosis confirmed by necropsy, surgery, subcutaneous or intraocular cysticercus, x ray of the skull, and of 509 clinical observation with suggestive CSF changes. It is the purpose of this paper to appreciate the importance of each of the CSF tests and to observe the CSF abnormalities during the course of this disease. The results of the study of the 79 cases varified by necropsy or surgery showed that the characteristic CSF changes that make the diagnosis of brain cysticercosis were observed in 54 percent of the cases. The eosinophils were present in 82 percent, protein changes in 78 percent, complement fixation test in 70 per cent, hypertension in 55 per cent, and decreased sugar content in 27 per cent of the cases. In two cases the CSF was normal. As the eosinophils and the protein abnormalities may be seen in several other diseases, the complement fixation test for cysticercus should be regarded as the most important CSF test in the diagnosis of brain cysticercosis. The successive CSF specimens withdrawn of 40 patients during the course of this disease have shown that the abnormalities went on for 4 to 18 years observation, suggesting that the parasites were alive. On the contrary, in 11 other cases it was varified the final CSF normalization after 5 to 14 years, suggesting that the parasites were dead. The CSF was normal in 31 out of 42 patients with opaque nodules visible in skull films (calcified cysticercus). In the remaining 11 cases, the characteristic CSF findings were observed in 3, but in 8 cases the only abnormalities were positive complement fixation test or eosinophils. In 14 out of 26 patients with subcutaneous or introacular cysticercus there were the usual CSF changes but in the other remaining cases the CSF was normal. The absence of treatment for brain cysticercosis is consistent with the persistence of CSF abnormalities in the specimens examined during the course of this disease. This calls for an integrated prophylactic to all Latin-American countries in order to exterminate this serious disease for the well-being of the next generation.