Blood culture and polymerase chain reaction for the diagnosis of the chronic phase of human infection with Trypanosoma cruzi.

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.

[Specific treatment attempt, with ticlopidine, of patients with Chagas disease chronic phase]. / Tentativa de tratamento específico, por meio da ticlopidina, de pacientes com doença de Chagas em fase crônica.

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.