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Map of the Madeira-Mamoré Railroad, located in what is now the state of Rondônia, built between 1907 and 1912. It ran for 227 miles (366 km) and linked Porto Velho to Guajará-Mirim. 1904. Coleção de Jorge A. Ferreira Jr. Revista Kosmos

After the cycle of major sanitary campaigns came to an end in Rio de Janeiro, the Oswaldo Cruz Institute was called on to combat epidemic outbreaks and cases of endemic disease across the country. Under contracts with public and private agencies, Cruz organized scientific and prevention expeditions that helped disseminate the campaign model.

Malaria was the first major problem tackled. Two missions, both led by Carlos Chagas, played an outstanding role in this battle. The first took place in Itatinga, in the interior of São Paulo, where the Companhia Docas de Santos was building a hydroelectric power plant. This 1905 campaign was Brazil’s first successful initiative against malaria and served as a model for subsequent efforts. The second mission took place in northern Minas Gerais, where Carlos Chagas headed in mid-1907 in the company of Belisário Penna. It was there in the small town of Lassance, two years later, that Chagas was to discover American trypanosomiasis, the disease that now bears his name.

Much as these expeditions were successful, institute staff took their most important trips from 1910 to 1913. While the targets of the earlier campaigns had been quite specific and limited to small areas, the institute’s new missions covered vast territories from the Northeast to the Amazon and also in the Central-West. These expeditions were motivated not only by the fight against epidemics but above all by the quest to advance science, and they furnished a veritable inventory of the living conditions and state of health of people living in the interior of Brazil.

Cruz himself led two of these expeditions, both in 1910. Along with Belisário Penna, he first visited Porto Velho, Roraima, where the Madeira-Mamoré Railroad was being laid. The enterprise had earned the nickname Devil’s Railway because malaria (among other illnesses) had killed so many of its workers. Since there was really no way to clean up the area, Cruz enacted tough measures: employees had to take massive doses of quinine every day and at nightfall had to confine themselves to their quarters, under the protection of mosquito netting.

The second mission got underway in November 1910, when, at the request of the government of Pará, the fight began against a yellow fever epidemic raging through the city of Belém. Cruz adopted the same prevention measures he had used in the sanitation of Rio de Janeiro: a relentless attack on mosquitoes, isolation of the ill, and fumigation and decontamination. The disease was eradicated in just six months.

Other expeditions traveled the interior of the country from 1911 to 1913 without the presence of Cruz. Astrogildo Machado and Antônio Martins were in the São Francisco and Tocantins river valleys; Arthur Neiva and Belisário Penna traversed Goiás, Pernambuco, Bahia, and Piauí; José Gomes de Faria and João Pedro de Albuquerque visited Piauí and Ceará; Adolfo Lutz and Astrogildo Machado sailed down the São Francisco River from Pirapora, Minas Gerais, to Juazeiro, Bahia; lastly, Carlos Chagas, Pacheco Leão, and João Pedroso journeyed through an immense area of the Amazon Basin.

All of these travels revealed a Brazil unknown to most Brazilians. Some sectors of the country’s political and intellectual elites were deeply moved when they saw the suffering of these people and their atrocious living conditions. The upshot was the formation of a movement for the sanitation of rural Brazil, out of which was born the Pro-Sanitation League of Brazil in 1918. The key objective of the League, led by Belisário Penna, was to bring about the enactment of a nationwide public health policy centralized within the federal government. A number of its ideas came to fruition some years after Cruz’s death.