[Show abstract][Hide abstract] ABSTRACT: Thirty-five individuals from endemic areas of Central Brazil (age range, 18-64 years; 19 women) in the chronic phase of Chagas disease, with positive serology and presence of circulating parasites detected by one or more recent positive xenodiagnosis, were selected for this study. Allopurinol (900 mg/d) or placebo was administered in a double-blind clinical trial for 60 days. After codes were broken, 23 had been allocated to the intervention group and 12 to the placebo group. Side effects were observed in 11 patients in the intervention group and in 1 in the placebo group. Seventeen patients in the intervention group and 10 in the placebo group completed the trial. Follow-up was performed by monthly xenodiagnosis and serologic tests every 3 months during the first year and at the end of the trial. Xenodiagnosis remained positive in all 17 of the treated group and in all 10 of the placebo group. Serologic tests were persistently positive in both groups after treatment. We concluded that, at the doses used, allopurinol was not effective to clear, in our region, Trypanosoma cruzi from peripheral blood of infected individuals.
The American journal of tropical medicine and hygiene 02/2007; 76(1):58-61. · 2.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chagas' disease is an important health problem in Latin America, and cardiac involvement is associated with substantial morbidity and mortality. We developed a model to predict the risk of death in patients with Chagas' heart disease.
We retrospectively evaluated 424 outpatients from a regional Brazilian cohort. The association of potential risk factors with death was tested by Cox proportional-hazards analysis, and a risk score was created. The model was validated in 153 patients from a separate community hospital.
During a mean follow-up of 7.9 years, 130 patients in the development cohort died. Six independent prognostic factors were identified, and each was assigned a number of points proportional to its regression coefficient: New York Heart Association class III or IV (5 points), evidence of cardiomegaly on radiography (5 points), left ventricular systolic dysfunction on echocardiography (3 points), nonsustained ventricular tachycardia on 24-hour Holter monitoring (3 points), low QRS voltage on electrocardiography (2 points), and male sex (2 points). We calculated risk scores for each patient and defined three risk groups: low risk (0 to 6 points), intermediate risk (7 to 11 points), and high risk (12 to 20 points). In the development cohort, the 10-year mortality rates for these three groups were 10 percent, 44 percent, and 84 percent, respectively. In the validation cohort, the corresponding mortality rates were 9 percent, 37 percent, and 85 percent. The C statistic for the point system was 0.84 in the development cohort and 0.81 in the validation cohort.
A simple risk score was developed to predict death in Chagas' heart disease and was validated in an independent cohort.
New England Journal of Medicine 09/2006; 355(8):799-808. · 51.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Maternal transmission of Trypanosoma cruzi from 278 children of 145 mothers, chronically infected with this protozoan, to their offspring was investigated. This study was based upon serological tests. In only two cases (2/278 = 0.70%), such mode of transmission was demonstrated to have occurred. However, as according to extant records both patients had also been breast-fed, and the contribution of this factor could not be ruled out. In any case, maternal transmission, an alternative mode of acquiring the infection with Trypanosoma cruzi, was demonstrated. The methodology used is a further contribution to the evaluation of the prevalence of this propagating mechanism of T. cruzi; in addition to those aimed at the main objective of the investigation, records were kept about pregnancy, parturition, puerperium, abortion, prematurity, perinatal deaths and breast-feeding, which might contribute to a better interpretation of the subject.
Revista da Sociedade Brasileira de Medicina Tropical 01/2004; 37(6):485-9. · 0.93 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ten patients with chronic Chagas' disease were treated with nifurtimox (8-9 mg/kg/day) associated with betamethasone (9 mg/day initially and then gradually reduced) during 60 days, with one exception. It was intended to combine the respective anti-parasitic and anti-inflammatory actions of these drugs. The expected stimulating effect of betamethasone on the infection could possibly enhance the anti-Trypanosoma cruzi action of nifurtimox. Long term persistence of negative xenodiagnosis, used to control the results, was observed in only one of the cases. Regaridng the other patients, post-treatment positivity of xenodiagnosis and serological testes attested the failure of this therapy. As this study has demonstrated, adequate and long term follow-up of treated cases is necessary to ensure correct conclusions.
Revista da Sociedade Brasileira de Medicina Tropical 12/2002; 35(6):547-50. · 0.93 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In the present study, we evaluated for the first time the profile of blood parasitism in untreated, chronic Chagas' disease. The study was conducted on 60 patients and a control group of nine serologically negative individuals. Analysis of three blood samples showed 70% cumulative positivity for blood culture and 86.7% positivity for PCR. The comparison of the two tests revealed that 41.1% (74/180) of the samples presented positive results for both PCR and blood culture, 22.2% (40/180) were positive for PCR alone, and 4.4% (8/180) were positive for blood culture and negative for PCR. The addition of the second sample raised positivity significantly for both blood culture ( P=0.0000) and PCR ( P=0.0369). Addition of the third sample was also statistically significant for blood culture ( P=0.0001) but not for PCR ( P=0.1186). These data point to the importance of studying the parasitemia of Trypanosoma cruzi-infected individuals before specific treatment. They also suggest that at least two blood samples should be collected and that two tests should be used, if possible--a procedure that considerably improves the parasitologic diagnosis of Chagas' disease and the evaluation of therapeutic efficacy.
Parasitology Research 11/2002; 88(10):894-900. · 2.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The validation of flow cytometry analysis of anti-live trypomastigote antibodies (FC-ALTA) to monitor cure after treatment of Chagas' disease was evaluated with serum samples from treated and nontreated chagasic patients. After optimization of the original technique, toward better sensitivity and applicability to field surveys, we design a double blind study of 94 coded samples classified into the following categories: patients not treated (NT) and patients treated but not cured (TNC), both presenting positive conventional serology and xenodiagnosis; patients treated and cured (TC), showing negative serology and xenodiagnosis; and patients treated under evaluation (TUE), who presented positive or oscillating conventional serology (CSA) but negative xenodiagnosis. Coded samples, diluted 1:256, were assayed by incubation with live cell culture trypomastigotes, which were subsequently stained with fluorescein isothiocyanate-conjugated anti-human immunoglobulin G, with prior fixation and analysis by flow cytometry. The results were expressed as the percentages of positive fluorescent parasites (PPFP) for each individual sample, establishing 20% PPFP as the cutoff between negative and positive results. Our data demonstrated that all NT and TNC presented positive results while all but one TC had a PPFP lower than 20%. Analysis of TUE demonstrated a wide degree of reactivity, with PPFP values that were negative (PPFP </= 20%), low positive (20% < PPFP </= 50%), and high positive (PPFP > 50%). As TUE with negative PPFP presented negative xenodiagnosis and positive or oscillating CSA, they were classified as dissociated according to the criteria of Krettli and Brener (J. Immunol. 128:2009-2012, 1982) and could indeed be considered cured after chemotherapy. This study demonstrates and validates the use of FC-ALTA to easily identify anti-live trypomastigote membrane-bound antibodies, offering another approach for investigating and monitoring the efficacy of specific chemotherapy in cases of human Chagas' disease.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to verify whether the amount of blood and number of triotomines used could improve the artificial xenodiagnosis performed in 200 chronic phase infected individuals. Ten or 40ml of peripheral blood was collected in heparinized (20.4 IU) vacuum tubes, and fed to 60 and 360 triatomines, respectively. Dipetalogaster maximus (1st instar, about 15 days after eclosion), as well as 3rd instar Triatoma infestans and Triatoma vitticeps and the 4th instar of Rhodnius neglectus were used. The faecal examinations were performed 30 and 60 days after xenodiagnosis procedure. The positivity with 10ml of blood was 19% and with 40ml, 44%, from which it was concluded that a correlation existed between the amount of blood and the number of triatomines used (p < 0.01). The positivity of the xenodiagnosis ranged from 9.7 to 100%, higher in young and adults up to 34 years old, but independent in relation to the sex of the chronic chagasic individuals studied.
Revista da Sociedade Brasileira de Medicina Tropical 01/2002; 35(1):29-33. · 0.93 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: From the emergency of acute cases of Chagas Disease in Montalvânia, Minas Gerais, Brazil, with the implementation of triatomine chemical control, the disappearing of these cases and the immediate reduction of incidence of the infection in the municipality are verified. The evolution of the dispersion and control of Triatoma infestans in Montalvânia and the evolution of the serology in general population during the last thirty years are showed.
Revista da Sociedade Brasileira de Medicina Tropical 36(6):719-27. · 0.93 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In a previous study, ticlopidine decreased the parasitemia and mortality of mice infected by Trypanosoma cruzi. Therefore, this drug was administered to 12 patients with Chagas' disease, in the chronic phase. For 90 days, 150, 200 or 250 mg were utilized according to whether the recipients were children, adolescents or adults, respectively. A fully unsuccessful outcome was documented, both serologically as well as parasitologically.
Revista da Sociedade Brasileira de Medicina Tropical 33(2):225-6. · 0.93 Impact Factor