A simple risk score was developed to predict death in Chagas' heart disease and was validated in an independent cohort.

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.

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.

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.

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