Effects of betamethasone on the course of experimental infection with Trypanosoma cruzi.

In this experiment, the effect o f betamethasone administered in the early postacute infection o f mice by Trypanosoma cruzi was studied. This drug was administered during 30 days after the 42nd day o f infection in a dose o f 0.15 mg/day. The betame­ thasone treatment did not cause fresh outbreaks o f parasitemia and the histopathological findings in the chronic phase were not different from those in the control group. The higher cumulative mortality after treatment in the experimental group was due to superimposed bacterial infections. Outbred albino mice infected with low numbers o f Y strain Trypanosoma cruzi trypomastigotes were not suitable models fo r Chagas' disease, since after 7 months o f observation only mild histological lesions developed in ali the animais. Prolonged betamethasone treatment o f mice infected with low num­ bers o/Trypanosoma cruzi o f the Y strain, during the post-acute phase did not aggravate the course o f infection.