Carlos Chagas

Carlos Chagas - Quick Facts

Profile Overview of Carlos Chagas

Carlos Justiniano Ribeiro Chagas (9 July 1879 – 8 November 1934), was a Brazilian sanitary physician, scientist, and microbiologist who worked as a clinician and researcher. Best known for the discovery of an eponymous protozoal infection called Chagas disease, also called American trypanosomiasis, he also discovered the causative fungi of the pneumocystis pneumonia. He described the two pathogens in 1909, while he was working at the Oswaldo Cruz Institute in Rio de Janeiro, and named the former Trypanosoma cruzi to honour his friend Oswaldo Cruz.

This profile of Carlos Chagas covers Early Life and Family Background, Early Career and Breakthrough, Chagas disease, Trypanosoma minasense and Pneumocystis and Personal Life.

Chagas's work holds a unique place in the history of medicine, Chagas described in detail a previously-unknown infectious disease, its pathogen, vector (Triatominae), host, clinical manifestations, and epidemiology. Chagas was also the first to discover and illustrate the parasitic fungal genus Pneumocystis, which later became infamous for being linked to pneumocystis pneumonia in AIDS patients.

Early Life and Family Background of Carlos Chagas

Chagas was the son of José Justiniano das Chagas, a coffee farmer at Juiz de Fora in Minas Gerais, and Mariana Cândida Chagas (née Ribeiro de Castro), both of Portuguese descent. His birth place is also recorded as Oliveira, his mother's hometown, where the family spent half of their times. He was the eldest of four children, and his father died when he was four years old. At age seven, his mother enrolled him to Jesuit boarding school in São Paulo. In 1888, a political turmoil erupted as Emperor Dom Pedro II declared abolition of slavery. Chagas was compelled to leave the school. His mother then transferred him to a nearer Catholic school called San Antonio, where he completed up to his secondary studies.

Chagas entered the School of Mining Engineering at Ouro Preto, but suffered from beri-beri in 1895 that incapacitated him from continuing those studies. While recovering in Oliveira, his uncle Carlos Ribeiro de Castro, an established physician, persuaded him to take up medicine. In 1896, he joined the Medical School of Rio de Janeiro (now the Federal University of Rio de Janeiro). For his dissertation, his mentor, Francisco Fajardo, suggested that he work on malaria, as the process of its transmission had been discovered by a British medical officer Ronald Ross in India in 1898.

For the dissertation research, Fajardo introduced Chagas to Oswaldo Cruz (1872–1917) founder of the Manguinhos Institute (which was later renamed after Cruz) who would be most suitable to guide him. This led to a lasting friendship between Chagas and Cruz, and Chagas's lifelong association with Cruz's institute. He graduated in 1902 with a dissertation on malaria and earned his doctorate the following year with a thesis on Estudos Hematológicos do Impaludismo (Hematological Studies on Malaria).

Early Career and Breakthrough of Carlos Chagas

After a brief stint as a medical practitioner in the hinterlands, Chagas accepted a position in anti-malarial campaigns. In 1905, he worked under the Docas de Santos company in the port authority of Santos, São Paulo, with the mission of fighting the malaria epidemic, which was affecting its workers. With successful malaria prevention, the company could complete construction on the port. There, he introduced an innovation, which consisted in using pyrethrum, an insecticide, to treat households, with surprising success. His published work on this method served as the basis of prevention of malaria all over the world, and was adopted by a service of the Ministry of Health in Brazil, which was established expressly for this purpose.

In 1906, Chagas returned to Rio de Janeiro and joined the Oswaldo Cruz Institute, where he worked for the rest of his life. In 1907, there was an outbreak of malaria at the Minas Gerais hinterland, largely affecting railroad workers and greatly hampered the construction on new railway from Rio de Janeiro to the city of Belém in the Amazon. The Brazilian government asked Cruz for help. Cruz immediately assigned Chagas, with an assistant, Belisario Penna, to make the investigation. Camping at Lassance, a small town near the São Francisco River, Chagas stayed there for two years and could contain the infection after a year of work.

Chagas disease

During his investigation of malaria in Lassance, Chagas observed the peculiar infestation of the rural houses with a large hematophagous insect of the genus Triatoma, a kind of "assassin bug" or "kissing bug" (barbeiro, "barber" in Portuguese, so-called because it sucked the blood at night by biting the faces of its victims). In his "Historic Restrospect", Chagas described:

He discovered that the intestines of these insects harbored flagellate protozoans, a new species of the genus Trypanosoma, and could prove experimentally that it could be transmitted to marmoset monkeys that were bitten by the infected bug. Chagas named this new parasite Trypanosoma cruzi in honor of Oswaldo Cruz and later that year as Schizotrypanum cruzi, and then once again as Trypanosoma cruzi.

Chagas's initial suspicion that the parasite could infect human and other vertebrates was proven right: he soon found the parasites in the blood of a cat. He then looked for a girl, later identified as Berenice Soares de Moura, a two-year-old girl whom he had seen in the same hut where that cat had been a few weeks before. He took Berenice's blood samples on 14 April 1909, discovering for the first time the same Trypanosoma parasite in the human blood. He also observed parasitic inclusions in the brain and myocardium, which would explain some of the clinical manifestations in diseased people, and closed the proposed lifecycle of the parasite by suggesting that the armadillo could be its natural reservoir. To complete his work on the pathology of the new disease, Chagas described 27 cases of the acute form of the disease and performed more than 100 autopsies on patients who exhibited the chronic form.

Chagas's description of the new disease was to become a classic in medicine, and brought him domestic and international distinction. He also persuaded Argentine physician Salvador Mazza to research the epidemic, leading to the latter's confirmation of the existence of Trypanosoma cruzi in Argentina in 1927, and eventually to government action.

Upon discovering Trypanosoma cruzi as the parasite of humans, Chagas additionally discovered that the parasite was responsible for a deadly heart disease now known as Chagas heart disease or Chagas cardiomyopathy. In 1909, he reported in the Brazilian medical journal, Brazil Médico, a case of human trypanosomiasis and noted the association with severe heart disease. In 1910, he further noticed that the parasitic infection could be classified into at least three different conditions, chronic heart disease, brain disorder, and thyroid problem, especially of goiter. He made an autopsy report of an individual with heart failure whom he found to have heavy trypanosome infection that was associated with blood cell accumulation (interstitial mononuclear cell infiltration) in the heart.

Source: adapted from Wikipedia (https://en.wikipedia.org/wiki/Carlos_Chagas), text available under CC BY-SA 4.0.