A new disease entity in man: a report on etiologic and clinical observations.

First, a quick review of the background: while working in a malaria-control campaign in the northern section of the state of Minas Gerais, we came across a large bug locally called “barbeiro,” which, like the bedbug, infests homes and attacks man at night, when the lights are out. Since this was a blood-sucking insect and such insects are of importance in human and animal pathology as vectors of disease, we examined “barbeiro” specimens and found in their hindguts a flagellate of crithidial morphology. The next step was to ascertain whether this flagellate was just a parasite of the insect or a stage in the life cycle of a parasite of vertebrates. In almost all marmoset (Callithrix penicillata) specimens from the same region, we had found a parasitic trypanosome. We suspected that the “barbeiro” was the intermediate host, and the flagellate forms in its gut were stages in the life cycle of this parasite, Trypanosoma minusense Chagas. Because of this, we sent specimens of the bug to our director and teacher Dr. Oswaldo Cruz, who had them feed on a marmoset. Dr. Cruz succeeded in infecting this marmoset with a hemoflagellate which, being quite different in morphology from Trypanosoma minasense, we named Trypanosoma cruzi. I studied the new parasite and found, through repeated experiments, that the insect was indeed the intermediate host, and that it took at least eight days after a bite for transmission to take place. I then made another trip to Minas Gerais for the purpose of establishing the definitive habitual host of the flagellate. The habits of the “barbeiro” suggested a situation of intradomiciliary infection; we were most impressed by the poor state of health of those who lived in infested houses. After conducting physical examinations, we found that the affected persons, especially the children, showed symp-