Combined treatment with a nitrofuranic and a corticoid in experimental Chagas' disease in the dog.

In order to study the effect of combined treatment of Trypanosoma cruzi infection with a nitrofuranic drug and a corticoid, 27 dogs from three different litters infected with T. cruzi (12 SF strain) were randomly litter-paired in three experimental groups: animals infected and not treated; infected and treated with Bay 2502 (2-methyl-4-[5'nitrofurfurylideneamino]-tetrahydro-4H-1,4-thiazine-1,1-dioxine) (nifurtimox); infected and treated with nifurtimox plus betamethasone. While an enhanced myocarditis appeared in the animals treated with a nitrofuranic drug alone, inflammation was almost abolished when corticoid treatment was added. Both groups showed considerable intracellular parasite destruction. These changes were monitored by serial electrocardiograms and a final histopathologic study which included an investigation of the changes in the conducting tissue by serial sectioning. The survival period was prolonged in animals treated with the combination of the nitrofuranic drug and corticoid, and only in this group did some of the animals reach the chronic phase of the infection. Thus, the association of a nitrofuranic drug with a corticoid in the treatment of acute Chagas' disease produced parasite destruction and inhibited the inflammatory responses that are enhanced by such destruction