Oswaldo Cruz and the eradication of infectious diseases in Brazil

Robert Perlman
Chicago, Illinois, United States


Photo of buildings on Rue Oswaldo Cruz, a street in Paris
Photo of buildings on Rue Oswaldo-Cruz, a street in Paris named after the physician. Photo from Wikimedia by user CVB. CC BY-SA 4.0

In 1899, an epidemic of bubonic plague caused a crisis in the Brazilian port city of Santos. Ship captains were angry that their boats had to remain in quarantine and so denied that the disease was plague. They and others argued that this new disease was not as deadly as plague (indeed, most cases were bubonic plague, which has a lower mortality rate than the pneumonic form of the disease), and some people dismissed the Brazilian authorities as not competent to diagnose plague. As the epidemic was raging, the government sent Oswaldo Gonçalves Cruz, a young Brazilian physician, to help combat the disease in Santos. Cruz had recently returned to Brazil after studying for three years at the Pasteur Institute in Paris but had no public health experience. His work in Santos was the beginning of an outstanding career.

Oswaldo Cruz was born in 1872 in São Luis do Paraitinga, a small town near São Paolo, but grew up and went to school in Rio de Janeiro. He became interested in infectious diseases while in medical school. In 1896, several years after graduation, he went to the Pasteur Institute; he was the first Brazilian to study there.1 These were exciting times in medicine. Pasteur had recently developed the germ theory, which posited that infectious diseases were caused by microscopic organisms that could be transmitted among people. Together with Robert Koch in Germany, Pasteur developed methods to isolate the disease-causing bacteria. Their work led to an interest in the mechanisms of transmission of infectious agents and in developing vaccines to prevent infectious diseases and antisera to treat infected patients. His studies at the Pasteur Institute familiarized Cruz with these advances in medical thinking and practice.

In 1900, the Brazilian government created the Federal Serotherapy Institute to produce anti-plague antiserum—then the best way of treating plague. Cruz was appointed technical director of the Institute and in 1902 became director. Under his direction, the institute expanded to become a research institute. Cruz oversaw the production of antiserum against plague and instituted interventions to prevent its spread. Effective public health practices often provoke controversy because they are at odds with individual autonomy. Cruz’s work was no exception. In Santos, Cruz organized teams of sanitation workers to kill rats, which included the unwelcome practice of entering homes and tearing up rat-infested flooring. He created a registry of infected patients and quarantined them, another unpopular directive. Although some of Cruz’s methods were controversial, he succeeded in virtually eliminating plague from the city. Unfortunately, plague spread to other port cities, including Rio, but the approach Cruz developed in Santos reduced the prevalence of the disease there as well.

In 1902, Francisco de Paula Rodrigues Alves was elected President of Brazil. He continued an ambitious urban renewal program begun by his predecessors to modernize or “civilize” Rio, as the program came to be known.2 At that time, sugar and coffee plantation owners wanted to attract European workers to replace the African slaves on which they had depended. (Brazil abolished slavery in 1888; it was the last country in the Western Hemisphere to do so.) The Brazilian government was also eager to attract European business and investment. Brazil was in competition with Argentina for European capital and labor; Rio was in competition with Buenos Aires for this commerce. Rio had the advantage of great physical beauty but had a much higher burden of infectious diseases, and suffered from recurrent epidemics of yellow fever, smallpox, malaria, and plague. Rodrigues Alves understood that these diseases prevented Rio from becoming an attractive destination for Brazilian citizens or for foreign workers and capital, and he turned his attention to eradicating communicable diseases in the city. He appointed Cruz as Director General of Public Health over the objections of people who were suspicious of the new ideas about infectious diseases.

Cruz’s first task as Director General of Public Health was to eradicate yellow fever from Rio. Yellow fever had come to Brazil in the seventeenth century, most probably due to the slave trade. It became a prominent disease in the nineteenth century and was first reported in Rio in 1850. Yellow fever was such a feared disease that at least one emperor refused to mention its name but referred only to “an epidemic fever” in the city, and physicians who diagnosed it were criticized as “meddlesome foreigners” or even branded as terrorists.3 After that, there were recurrent epidemics of yellow fever in Rio for the rest of the nineteenth century.

At this time, the cause of yellow fever was not known. Many physicians believed that it was due to miasmas, or bad air, and advised people to live outside of cities, where the air was cleaner. Others thought that yellow fever was spread by the secretions of infected people and recommended disinfecting their clothing. The Cuban physician Carlos Finlay and the American physician Walter Reed had recently demonstrated that yellow fever was spread by mosquitoes, and they had used this knowledge to kill mosquitoes, poison their breeding grounds, and isolate or quarantine infected patients to rid Havana of yellow fever.4 Cruz used the same strategy in Rio. This was controversial within the medical profession. Some physicians still clung to the miasma theory and others were skeptical of the infectious origin of yellow fever because its virus had not yet been isolated.

As in Santos, people were angry that sanitation workers could enter their homes, spray a foul-smelling disinfectant (probably phenol, or carbolic acid) on their walls, and if the house was too dilapidated recommend it be torn down. Quarantining infected patients was seen as an infringement of individual liberty and was also bad for business. But Cruz persisted and with the support of Rodrigues Alves was successful: yellow fever was eliminated from Rio by 1907 and its incidence in the rest of Brazil was greatly reduced.

Cruz then turned his attention to smallpox and persuaded the government to mandate vaccination. This angered people who felt that the government’s urban renewal programs benefited the wealthy at the expense of the workers as well as those who resented yet another infringement on their autonomy, and led to the Vaccine Revolt of 1904.5 This went on for a week and almost led to the fall of the government, but order was restored when the government rescinded the compulsory vaccine law. Although there was much anger against the government, it was not directed at Cruz himself or at the Department of Public Health. In 1908, there was an epidemic of smallpox in Rio. By that time, objections to vaccination had waned and many people came voluntarily to be vaccinated. Progress in eliminating smallpox slowed because of changing government priorities but the disease was finally eradicated by 1973.6

Cruz was honored in Brazil and internationally for his work. In 1907, he received a gold medal from the XIV International Congress on Hygiene and Demography. In 1908 the Federal Serotherapy Institute was renamed the Oswaldo Cruz Institute. Perhaps the most memorable tribute to Cruz came from the Chicago surgeon Nicholas Senn. In 1907, Senn toured medical institutions in South America and sent back travel notes that were published in the Journal of the American Medical Association. One of his articles was devoted to Oswaldo Cruz and the National Board of Public Health in Brazil.7 After praising Cruz’s work against yellow fever and bubonic plague, Senn concluded:

“A life-sized statue in pure solid gold to his memory would be but a feeble acknowledgement of the invaluable services he has rendered to his country.”

Cruz suffered from Bright’s Disease and in 1915 he retired from his professional work; he died in 1917, at age forty-four. He is still honored for his many contributions, and the Oswaldo Cruz Institute remains the premier public health research institute in Brazil and one of the foremost in South America.



  1. Stepan, N. Beginnings of Brazilian Science: Oswaldo Cruz, medical research and policy, 1890–1920. New York: Science History Publications, 1981.
  2. Meade T. “Civilizing” Rio: reform and resistance in a Brazilian city. Penn State Univ. Press, 1996.
  3. Cooper DB. Brazil’s long fight against epidemic disease, 1849–1917, with special emphasis on yellow fever. Bull NY Acad Med 51, 672–696, 1975.
  4. Chaves-Carballo E. Carlos J. Finlay: the mosquito man. Hektoen Int’l 13, No 1, 2021.
  5. Perlman R. Lessons from the Vaccine Revolt of 1904. The Bulwark, November 14, 2020 < https://thebulwark.com/author/robert-perlman/>.
  6. Hochman G. Priority, invisibility and eradication: the history of smallpox and the Brazilian public health agenda. Med Hist 53, 229–252, 2009.
  7. Senn N. Travel notes from South America IV. Work of the National Board of Public Health of the Republic of Brazil. J Amer Med Assoc 49, 1356–1361, 1907.



ROBERT L. PERLMAN received M.D. and Ph.D. (Biochemistry) degrees from the University of Chicago and is now a Professor Emeritus from the university. Interested in the field of evolutionary medicine, he is the author of Evolution and Medicine, Oxford University Press, 2013. Robert’s fascination with Oswaldo Cruz and his work grew out of his interests in host-parasite coevolution and more broadly in infectious diseases and public health. He recently published a short online essay, Lessons from the Vaccine Revolt of 1904, The Bulwark, November 14, 2020, which discusses the response to the compulsory vaccination law mentioned here.


Spring 2021  |  Sections  |  Infectious Diseases