Chagas and American trypanosomiasis

In 1907 malaria was stalling the extension of the Central do Brasil railroad between Corinto and Pirapora in northern Minas Gerais. The institute at Manguinhos in Rio de Janeiro, renamed for its director Oswaldo Cruz in 1908, sent Carlos Chagas, a young physician whose thesis was on malaria, to fight it. He based himself at Lassance, a small town on the São Francisco river.

A railroad engineer told him about the barbeiro, a blood-sucking bug that bred in the walls of the region’s wattle-and-daub huts and bit sleepers on the face. With no laboratory at Lassance, Chagas sent bugs to Manguinhos, where Cruz let them bite laboratory-bred marmosets; one fell ill with trypanosomes in its blood. Chagas, who also found the parasite in the bugs’ hindgut, named the new species Trypanosoma cruzi, after Cruz.

He next found it in a cat, and on 14 April 1909 in the blood of a feverish two-year-old girl, Berenice, who lived in the same hut. A note in Brazil-Medico announced a new human trypanosomiasis the next day, and on 22 April Cruz reported vector, parasite and disease to the National Academy of Medicine. A long paper in the institute’s Memórias followed in August, and a full clinical and epidemiological account in 1911. Rachel Lewinsohn of Cambridge later observed that Chagas had worked backward, from a possible vector to a possible parasite and only then to the disease.

Not all of the early clinical picture held. Chagas at first folded the region’s endemic goiter into the new disease, calling it parasitic goiter; the French historian François Delaporte later argued that this merged two separate conditions. In 1922 and 1923 a dispute in the National Academy of Medicine, led by the hygiene professor Afrânio Peixoto, cast it as a mere illness of Lassance; Peixoto held that stressing tropical disease hurt Brazil’s image abroad. Chagas directed the Oswaldo Cruz Institute from 1917 until his death in 1934, at 55.

Doctors in Belo Horizonte examined Berenice in 1961, at 53, and found her still a carrier and in good health. The World Health Organization estimates that about 8 million people, mostly in Latin America, are infected with T. cruzi, and that the infection causes more than 10,000 deaths a year. Since 2020, 14 April has been World Chagas Disease Day.