EVALUATION OF THE RABBIT AS A MODEL FOR CHAGAS-DISEASE .2. HISTOPATHOLOGIC STUDIES OF THE HEART, DIGESTIVE-TRACT AND SKELETAL-MUSCLE

In order to investigate the value of the rabbit as an experimental mod el for Chagas' disease, seventy one animals were inoculated with diffe rent Trypanosoma cruzi strains and routes. The rabbits were submitted to necropsy in acute (earlier than three months of infection), recent chronic (three to six months) and late chronic (later than six months) phases. Myocarditis, generally focal and endomysial, occurred in 94.1 %, 66.7% and 70.8% of the infected rabbits respectively in the acute, recent chronic and late chronic phases. The myocardial inflammatory ex udate was composed by mononuclear cells, and also polymorphonuclear ce lls in the acute phase. In most cases of the late chronic phase, the m yocarditis was similar to that described in the indeterminate form of human chagasic patients. Initial fibrosis occurred in the three phases but was more severe and frequent in the early chronic. Advanced fibro sis occurred only in the late chronic phase. Tissue parasites occurred only in the acute phase. The digestive tract and skeletal muscles sho wed mild and occasional lesions. Our data indicate that experimentally infected chagasic rabbits repeat some lesions similar to that of huma ns chagasic patients, specially that of the indeterminate form. So, it may be a useful, however not an ideal, model.