Investigation on the possibility of spontaneous cure of mice infected with different strains of Trypanosoma cruzi

Abstract

Seventy Swiss mice chronically infected with different strains of Trypanosoma cruzi, with persistentiy negative parasitemia on routine blood examination were parasitologicaily investigated to find out whether spontaneous cure occurred. Duration of infection varied from 90 to 250 days in the initial phase of this investigation. Parasitologicai tests consisted of daily direct blood examination performed during at least 25 days, foliowed by xenodiagnosis and subinocuiation of blood into newborn mice. Mice that persisted negative were treated with Cyciophosphamide with one dose of 250 mg!kg of body weight and then investigated by direct blood examination, xenodiagnosis and subinoculation. A second dose of 250 mgfkg b. w. was given to the persistentiy negative mice. With one single exception, ali mice showed positive parasitoiogicai tests in the different stages ofthe present investigation and we conciude that spontaneous cure did not occur in this group, which is representa- tive of the chronic infection with different strains of T. cruzi.