The Impact of Epidemiological Change on Disease Categories
Friday, December 19, 2014 at 9:10AM
Ian Read

Historians of medicine often consider nosology, or the classification and naming of disease, to be culture-bound and ethnocentric.   For example, Charles Rosenberg and Janet Golden write that “in some ways disease does not exist until we have agreed that it does, by perceiving, naming and responding to it” (1992, xii).  In Illness as a Metaphor, Susan Sontag describes the powerful ways that the meanings of particular diseases expand and take mythic proportions far removed from any biological operations on the body.  For many Brazilians living in the middle of the nineteenth century, diseases like cholera and yellow fever were indeed metaphors of filth, bad odors, and pollution.  Until their microbes were discovered in the late 1800s and the idea of germs became popular, medical and ruling elite understood these two diseases as caused by similar filthy conditions: Rotting and noisome organic material that exuded dangerous gasses and were the catalysts of disease.  Physical weaknesses and behavior prone to moralizing, such as intemperance, could predispose infection as well. 

History and culture certainly matter because the environmental etiology of many so-called infectious (i.e., miasmatic) diseases was a European colonial and ideological import into the Americas, conceived of by the ancient Greeks and renewed by writers such as Robert Boyle (1627-1691) and Edwin Chadwick (1800-1890). The neo-Hippocratic emphasis on the environment of disease and “unsanitary” conditions in the eighteenth and nineteenth centuries provided a useful framework for making sense of yellow fever and cholera, but we go too far to say that this dominant paradigm was the reason why Brazilians identified cholera and yellow fever in the first place.  When these two diseases unexpectedly appeared in Brazil in destructive waves of epidemics in the 1850s, they were perceived as new and unique diseases to Brazil regardless of whether they were caused by (generally preventable) accidents of local environmental degradation, the wrath of God for a people’s sins, the multiplicity of factors within diverse etiological understandings by indigenous and Africans, or a combination of these various perspectives. 

Diario de Rio De Janeiro, 23 March 1850, pg. 1

The ways that environment and ecology can “frame” culture, or at least strongly influence beliefs about the operation of the natural world is at the heart of my book project.  Historians of medicine usually emphasize the opposite, or the ways that culture frames diseases.  But when the epidemiological environment changed drastically in Brazil and horrifying epidemics struck and killed hundreds of thousands of people throughout the country in the 1850s, categories of disease altered as much in the face of a new ecological reality as they did by views of infection and contagion that shifted in interconnected ways across the Atlantic World.  In other words, cultural categories matter, but so do the profound changes in the relationship between people and microbes.

One way to explore this idea is to examine how Brazilian newspapers printed particular words across the wide expanse of this continental country and over time.  Using the Brazilian National Library’s online newspaper database, it is possible to compare the frequency of any word or combination of characters.   I use a “frequency score” that places the three most common three-letter words in the Portuguese vocabulary (“que,” “por,” and “dos”) as a baseline.  The usage of these popular words do not appear to have changed greatly and an average of the three reduces fluctuation.  A frequency score of “10” indicates that the average usage of the three short common words was about 100 times greater than the frequency of the word measured.  Likewise, a score of “100” signifies there are about 10 of each of the three commonest words for every single instance of the word measured.  The frequency score, therefore, allows us to find the relative use of a term regardless of the fact that the total number of pages and words printed on each page altered decade to decade.

For example, the words “cholera” and “morbus” went from very rare to common in newspapers across the empire between 1800 to 1879.  Their peaks occurred in the 1850s, precisely when cholera took the most lives in Brazil:


“Cholera” or “cholera morbus” referred to a dangerous physical affliction typified by frequent diarrhea and vomiting, dehydration, “rice-water” dejections, and grayish-bluish skin.  “Colera” – without the “h” – had a different meaning and is synonymous with “anger” or “rage.”  It was often connected to the divine action, such as the “colera de Deus” or “God’s wrath.”  This word also became more common in Brazilian newspapers, but its rise preceded the appearance of “cholera” and its more frequent discussion in Brazilian newspapers.   I'll come back to this interesting pair of homophones.   

We can also see an increase in words relating to the intensity and destruction of disease.  Three words:  “epidemia” (epidemic), “peste” (pestilence or plague), and “flagello” (scourge or plague) demonstrate shifts in usage:


Again Brazilian newspapers increasingly print these words, with a peak during the 1850s.  These words were also used in reference to other epidemics of the day, including yellow fever and smallpox.  In fact, yellow fever was a worse problem in the 1850s and 1870s, and this may explain the dip in these terms’ usage in the 1860s.  “Peste” and “flagello” have more religious connotations, and can infer the actions of a Christian God reacting to a people’s moral behavior.  The fact that “epidemia” surpassed these two words at this time may hint at a secularization of society.  The historians João José Reis and Claudia Rodrigues present strong evidence that burial traditions also demonstrate a steady secularization in the 1800s, especially at the moments of these outbreaks.

In all cases, the increasing use of these words corresponds with sharp rises in the mortality and destruction of several unfamiliar diseases (cholera and yellow fever) or familiar but worsening diseases (smallpox).  Some may argue that use of language, and the cultural categories it expresses, was driving the perception of these diseases.  This might be partially true.  For instance, when cholera’s homophone “colera” became more commonly printed in Brazilian newspapers, did it make the arrival of “cholera” a more fearsome event because a conscious or unconscious association with God’s wrath?  From the movement of these charts, however, it appears that language was largely reactionary.  To put it another way, when these diseases arrived, people talked more about them, but in ways that shifted gradually over time.  

Article originally appeared on Era of Epidemics: A Spatial Approach to Disease and History in Imperial Brazil (
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