Throughout human history, diseases have always been perceived as originating from nature and interpersonal relationships. However, for many centuries this perception was linked to mystical interpretations that managed to explain the then inexplicable. At the same time that possible sins were pointed out as the cause of an illness, it was suggested that the solution to combating it would be the purification of souls, thoughts and bodies.
From the mid-18th century onwards, other justifications for the outbreak of diseases were sought, through a greater understanding of the environment and its relationships with living beings. Until then, the notion of climate was astrological; but with the progress of the sciences, this notion extended to minute observations that could be objectively measured, analyzed and compared.
In the era of European empires, the hot and humid tropics they colonized served as an explanation for how some diseases were distributed to certain regions, with different impacts and endemic patterns for different populations. An individual outside their original environment could suffer serious consequences and lose their health. A notable example of these studies is James Lind (1707-1782), who in 1768 wrote “Essay on diseases incidental to Europeans in hot climates”, a product of his experience in the West Indies. The author noted that some diseases common among the native population were particularly fatal to Europeans.
During the 1840th century, the concept remained that the tropics led the white man to an early grave and to yellow fever, among other diseases. However, yellow fever at times seemed to be the exception to the rule, as its behavior deviated from the concept of “tropical”. The disease not only reached high mortality rates in West Africa, the Caribbean and Central America, but also in the southern United States, where it caused terror in the port areas of Memphis, Mobile and New Orleans. Likewise, outbreaks that broke out in Lisbon, Barcelona, Cádiz and Málaga during the 1870th century and in British and French ports in the XNUMXs and XNUMXs, distorted any pre-conceived etiological ideas. But there were major military defeats, particularly in Colombia (Cartagena), India and Haiti, where soldiers were decimated by yellow fever, which aroused special interest in European nations in its etiology and combat.
Two medical schools fought over its origins. Contagionists argued that the disease was transmitted through direct physical contact, through objects handled by patients, or even through the air they had breathed. On the other hand, for followers of the infection theory (non-contagionists), yellow fever arose through the action of putrefactive products and their influence on the environment, represented by elements as tenuous as they were enigmatic – miasmas.
The term “miasma” was derived from Greek and meant stain or pollution, but it was implied that miasmatic diseases spread through the air. Despite the conceptual difference, these two lines of thought were not exclusive and, often, they were combined in medical and lay explanations about the most diverse epidemics.
Both theories accepted that the hot and humid climate seemed to worsen yellow fever outbreaks, and coastal areas met these conditions that were believed to be ideal. Equally divided between contagionists and non-contagionists, Brazilian doctors supported these ideas. Dr. Antenor Guimarães, collaborator of the Journal of Medical and Surgical Sciences, in an article published in July 1874, defended the non-contagiousness of yellow fever and understood it as typical of our country due to its intense heat, in addition to being linked to mysterious thermoelectric immigration causes. The author believed that the disease could attack Campinas even though, in his opinion, the city did not have sufficient conditions for its further development, and argued that it would never have an epidemic character if hygienic conditions were taken care of.
History would disprove Dr. Guimarães after the great epidemic of 1889 in Campinas. A problem for medicine at the time was explaining the presence of this outbreak in an economically relevant city, which caused a large influx of workers for its coffee farms, incipient industry and commerce, but which was strangely located very far from the coast. This was a mystery that would only be solved in the following century when Reed, a member of the American committee to investigate yellow fever, confirmed the ideas of Finlay (1881) and before him of Daniel Beauperthuy (1854) about transmission through the bite of a mosquito. .
In fact, the elucidation of diseases, including epidemic ones, gained momentum at the moment when its main focus shifted from smell and touch to the sense of sight. The bad smell had been identified for millennia as the cause of various illnesses, as well as the tactile sensation promoted by wind, heat or humidity. But it was the medical gaze focused on anatomical, structural and, finally, functional anomalies that helped drive the discovery of the true causes of illnesses, although it was complemented through a primordial multisensory structure.
From 1880 onwards, there was a significant increase in investments in medical education and, in particular, in experimental laboratories, driven by the first bacterial discoveries; and it was only then that epidemics were accepted as the result of the presence of specific microorganisms, transmitted in different ways and acting under certain determinants.
Prof. Dr. Cristina Brandt Friedrich Martin Gurgel
History of Health Sciences Study Group (GEHCS), FCM, Unicamp
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