Abstract

Infection of mice with Trypanosoma cruzi of the Perú strain was associated with the appearance in the circulation of a viral inhibitor that fulfilled most requirements for classification as an interferon. The inhibitor reached its highest titer several days after infection and persisted, although in diminishing amounts, in the circulation until the termination of the experiment. The peak response preceded by several days the marked parasitic multiplication as evidenced by the number of nests of amastigotes in the heart.