The history of dengue

New article describes the role of virological studies in understanding the disease’s evolution in Brazil

Until the early twentieth century, dengue was confused with other diseases, such as influenza. Not because of its causes, but because of its symptoms. The history of dengue remained unclear until it became widespread in Brazil in the 1980s, making it a greater focus of research in the country.

In an effort to understand the process triggered by the 1986 dengue epidemic in Rio de Janeiro and its contribution to systematic research on the virus at the Oswaldo Cruz Institute (IOC-FIOCRUZ), health historian Jorge Tibilletti de Lara conducted an analysis that was published in an issue of the journal História, Ciências, Saúde – Manguinhos (History, science, health – Manguinhos).

“There is the history of the virus’s identification, with its arrival in Brazil first confirmed in Boa Vista, Roraima, in 1981. Then in Nova Iguaçu, Rio de Janeiro, in 1986. Then there is the clinical history of the disease, which is much less clear,” says Lara, who is studying a PhD in the History of Science and Health at FIOCRUZ’s Casa de Oswaldo Cruz.

“That’s why I’m looking at the role of virological studies that aimed to understand the disease, taking into account the relationship between physicians and virologists.” The work—the result of Lara’s master’s degree—seeks to demonstrate the role played by dengue studies in shedding light on the disease at a time when it was still relatively unknown and was transitioning from a rare disease to a more common one.

The article analyzes the main impacts of the disease on the research center, the career of scientists, the incorporation of new laboratory techniques for studying arboviruses, and the role of virology in new public health problems.

“Arboviruses have a complex cycle that was discovered by virologists, resulting in clarification of the disease and the incorporation of new laboratory tests and methods, leading to a level of expertise in Brazilian virology that continues to this day,” writes Lara in the article.

In the 1980s, dengue was not even on the radar of most doctors and scientists—at least not in Brazil—although serious epidemics of the disease had occurred, such as in Havana, Cuba, in 1981.

“The differentiation, including between dengue and chikungunya, for example, was made in the lab,” explains the historian. “It was through isolation and identification of the viruses, which began in the 1950s, that clearer boundaries were revealed between these diseases. But this wasn’t reflected in clinical settings because they were not diagnosed in patients until at least the 1980s.”

According to Lara, although drawing parallels with other diseases (such as Zika, chikungunya, and COVID-19) is a “risky maneuver,” the perception of correlations between their trajectories over time is inevitable. There is a close relationship between the history of diseases transmitted by the mosquito Aedes aegypti, such as dengue, Zika, chikungunya, and yellow fever, both in identification of the viruses and in the establishment of diagnostic models.

Yellow fever, for example, served as a model for dengue studies when they were started in Brazil, because of its long history of consolidated research and the similarities between the two diseases and viruses. Similarly, when Zika emerged in Brazil, studies on dengue became references for new research.

With regard to COVID-19—which is viral in origin but not transmitted by mosquitoes—the article highlights that the speed of the research carried out by FIOCRUZ virologists and specialists nationwide when the pandemic began can be attributed at least partly to the expertise the country developed while studying the dengue virus.

“FIOCRUZ has historically operated in response to social demand—epidemics, vaccination, serums, etc.—through solid lines of biomedical research. This process was first highlighted in the 1970s by historian Nancy Stepan and is observable at the institution in various periods,” explains Lara.

As dengue established itself as a new urban arbovirus on a continental scale, a cooperative Pan-American effortbegan, with scientists working closely together across Latin America, says Gabriel Lopes, who has a PhD in the History of Science and Health from Casa de Oswaldo Cruz and the Department of the History of Medicine at Johns Hopkins University, USA. “In Brazil, from 1986 onwards, a close dialogue was developed with Cuban scientists who had successfully faced an unprecedented dengue epidemic back in 1981,” Lopes explains.

The history of science

Lara’s work is part of a research field called the history of science, which is closely linked to the history of health. These are “subdivisions” of history that focus on analyzing the historical characteristics that form what we know today as science.

In the history of health, historians seek to understand the interrelated cultural, political, social, and scientific processes behind the history of diseases, doctors, patients, vaccination campaigns, hospitals, and more.

In Brazil, as in the rest of the world, viruses were studied even before the existence of the consolidated discipline known as “virology.” Smallpox and yellow fever were the main diseases of viral origin studied in this context between the end of the nineteenth century and the early twentieth century.

The nation’s expertise on these biological entities was then developed throughout the twentieth century, with a greater focus after the 1950s in response to several epidemics of infectious diseases. And it changed with the emergence of certain scientific techniques and instruments.

Institutional and political factors and milestones, such as the 1964 military coup and the country’s redemocratization in 1985, also played a major role. All these processes directly affected the formation of research groups and the careers of many scientists.

Thus, when dengue appeared in 1986, although virology labs such as the Evandro Chagas Institute in Pará and the Oswaldo Cruz Institute already had extensive experience in studying viruses, dengue’s novelty and the challenge of understanding the mechanisms of a newly circulating virus, especially as a complex arbovirus (transmitted by arthropods), resulted in much new research in virology. This led to the development of new tools for the scientific discipline, including increased funding and visibility and dedicated departments and research groups.

The Brazilian Society of Virology (SBV) was created that same year of 1986, as was the Flavivirus Laboratory at FIOCRUZ’s Virology Department, where the dengue virus was isolated and continues to be systematically studied to this day.

“In this sense, I would say that dengue gave Brazilian virology significant experience, having become one of the main topics studied in the field alongside other arboviruses, as well as providing an excellent model for the study of other viruses,” says Lara, who is currently writing his doctoral thesis on the applications of radioisotopes in Brazilian biology research in the second half of the twentieth century.

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