Characterization of Trypanosoma cruzi populations by zymodemes: correlation with clinical picture.

Trypanosoma cruzi isolated from 55 chronic chagasic patients were grouped into isozymic strains on the basis of electrophoretic patterns for a set of six enzymes. The total sample showed a distribution of asymptomatic (63.6%) and clinically ill (36.4%) patients similar to that generally reported for Chagas' disease. Six of the 12 zymodemes known to exist in Argentina have been isolated from humans. Only two (Z1 and Z12) are frequent and widely distributed in the endemic area. These two zymodemes differ significantly in their pathogenicity. The proportion of asymptomatic patients was higher with the Z1 zymodeme (81.1%) than with the Z12 zymodeme (27.3%). The incidence of heart alterations was lower in Z1 than in Z12 zymodeme patients (18.9% versus 72.7%). Clinically evident acute disease was seen in 36.3% of cases with zymodeme Z12 and in 8.1% of cases with zymodeme Z1. The differences between the two prevalent zymodemes in Argentina are statistically significant. These observations indicate that the Z1 T. cruzi is a more benign strain than Z12. Patients infected with Z1 would be more likely to be asymptomatic for a longer time than those infected with Z12. The risk of cardiac lesion would be greater for patients harboring Z12 T. cruzi than for those with Z1. The results suggest that strain identification could be a useful prognostic tool.

Therapeutic efficacy of allopurinol in patients with chronic Chagas' disease.

Laboratory and animal studies have demonstrated that pyrazolopyrimidines have significant activity against Trypanosoma cruzi. This clinical investigation was to ascertain the efficacy of allopurinol in the treatment of chronic Chagas' disease. Of 307 patients studied, 91 were untreated; the remaining 216 were divided into 4 treatment groups. These corresponded to 600 or 900 mg/day of allopurinol for 60 days and benznidazole or nifurtimox at conventional dosage regimens. Patients were evaluated clinically, serologically, and parasitologically. Allopurinol was found to be as efficacious as the conventional therapeutic modalities in eliminating the parasitemia and rendering patients seronegative. Adverse reactions occurred in 11% of patients who received allopurinol and in 30% of those receiving nitrofurans. Reactions with the conventional therapy were more frequent and of a more serious nature. Oral allopurinol is as effective as the nitrofurans, but has none of the side effects.

Allopurinol Vs. testigo en la parasitemia de la enfermedad de chagas cronica asintomatica valorada por xenodiagnosticos seriados / Allopurinol and placebo in the evaluation by serial xenodiagnosis of the parasitemia of asimptomatic chronic Chagas disease

Se estudiaron 58 pacientes en total, siendo 26 mujeres y 32 varones. El promedio de edad fue semejante a los tres grupos (29+/-5,13 anos)La parasitemia fue evaluada mediante xenodiagnosticos seriados (Xd). Cada estudio se realizo con 4 cajas de 10 ninfas del 3er estadio del T. Infestans cada una de acuerdo a la tecnica de Cerisola y Col.> El personal que realizo la lectura en todos los casos ignoraba a que grupo pertenecia el paciente estudiado e igualmente si habia recibido tratamiento o no