Carlos Justiniano Ribeiro Chagas, or Carlos Chagas (Portuguese: [ˈkaʁluʒːuʃtʃĩniˈɐ̃nu ʁiˈbejɾu ˈʃaɡɐʃ], [ˈkaʁluˈʃːaɡɐʃ]; 1879–1934), was a Brazilian sanitary physician, scientist and bacteriologist who worked as a clinician and researcher. He discovered Chagas disease, also called American trypanosomiasis in 1909, while working at the Oswaldo Cruz Institute in Rio de Janeiro.