Carlos Juan Finlay and Yellow Fever

Carlos Juan Finlay was a Cuban doctor who did a lot of work to understand the spread of Yellow Fever. But Walter Reed got most of the credit.

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• 2:08Tracy V. Wilson?

  Welcome to Stuff You Missed in History Class, a production of iHeart Radio.

• 2:19Tracy V. Wilson?

  Hello and welcome to the podcast. I'm Tracy V. Wilson. And I'm Holly Frey. Way back in 2014, we did an episode on Walter Reed, which we reran as a Saturday classic, maybe three-ish years ago. Walter Reed was a US Army physician who was most known for his work on illnesses that were really affecting soldiers in the Caribbean, especially yellow fever. In that episode, we talked about how Reed's work was really based on that of a Cuban doctor named Carlos Juan Finlay. I'm going to take a pronunciation moment here because I think a lot of people in English-speaking countries pronounce that name, which is spelled F-I-N-L-A-Y, as Finlay.

• 3:04Tracy V. Wilson?

  But everything I found from an institute named after him and some things from Spanish speakers in Cuba pronounced it more like Finlay. So that's what we are going with. So Finlay had already figured out a lot of what Reed and his team confirmed and then were pretty much giving credit for. I've always wanted to talk more about Finlay, and now we are, finally. Juan Carlos Finlay was born on December 3, 1833. He was born in Camaguey in central Cuba, which was, at the time, known as Santa Maria del Puerto del Principe. He went by Carlos and later on in his life started using J as his middle initial to differentiate from his son, Carlos Eduardo Finlay,

• 3:48Tracy V. Wilson?

  who became an accomplished doctor and professor of medicine in his own right. Carlos's parents were both immigrants to Cuba. His mother, Elizabeth de Bard, known as Eliza, was a Frenchwoman from Trinidad. His father, Edward Finlay, was from Scotland. In the words of a biographical sketch by Cuban physician and yellow fever specialist, Dr. Juan Guitares, which was published in 1912, quote, "Like to one other great Antillan, Alexander Hamilton, he was born of two great races, the Scotch and the French." A quote I included in this episode because it made me laugh so hard when I read it for the first time.

• 4:31Tracy V. Wilson?

  Gutierrez also had this to say about Finlay's personality and what his parents' nationalities had to do with it. Quote, "From the Scotch, he inherited the intensity and the ardor in the pursuit of an objective, together with the logic, discipline, and the inclination to theorize upon, and insistently to discuss obstruse subjects without losing, however, the golden thread of their practical application. From the French, he received his characteristic amiability and courtesy, together with a lively imagination and the love of glory, which, though not apparent on the surface, must have spurred the Scotchman in his noble ambition." I feel like this is attributing a lot of stuff to his behavior that really, we have

• 5:16Tracy V. Wilson?

  no scientific basis for. But according to Gutierrez, that was tempered by, quote, "the most exquisite modesty, a virtue which, I am pleased to think, was fostered in the Creole atmosphere of the time, together with a great love for the land of his birth." Yeah, I really feel like that quote is a combination of a description of his personality and an example of how much people thought a national origin could affect a person's character. So at first, when Carlos was a child, he was educated at home. And when he was 11, his parents sent him to a school in France.

• 5:59Tracy V. Wilson?

  His father was a doctor and wanted him to have access to a prestigious European education, but that education wound up having a lot of interruptions. First, Carlos got sick. Most accounts describe this as chorea, possibly sydenham chorea, which is a movement disorder that can develop in children after they've had an illness like strep throat or scarlet fever. This affected his speech, and after Carlos got home, his father developed a regimen to try to help him recover, and it did help. For the rest of his life, Carlos spoke slowly, and his speech could sound slurred, which sometimes affected people's perceptions of

• 6:39Tracy V. Wilson?

  his intelligence. Gutierrez also suggested that this speech disorder came from Carlos's brain and might have been connected to his seeming perpetually absent-minded.

• 6:52Tracy V. Wilson?

  Carlos went back to France when he was 15, but before long, he had to leave again due to the Revolution of 1848, which overthrew France's constitutional monarchy. Carlos went to London for a while and then spent a year studying in Germany before going back to France and enrolling in college in Rouen. Then in 1851, he faced yet another interruption when he contracted typhoid fever and had to once again go back home to Cuba to recover. By this point, Finlay was fluent in Spanish, English, German, and French, and he knew enough classical Latin and Greek to translate works in those languages into Spanish for fun.

• 7:35Tracy V. Wilson?

  His coursework in Europe was equivalent to a Bachelor of Arts, and he had reached a point in his education that, once he recovered, the next step would be medical school. But the medical school at the University of Havana would not accept these credentials. So Finlay went to Philadelphia to attend Jefferson Medical College, earning his medical degree on March 10, 1855. His professors and mentors encouraged him to go to New York and work with the Spanish-speaking immigrant community there, but he wanted to go back to Cuba. He did, and Spanish authorities validated his medical degree and approved him to practice medicine there in 1857.

• 8:18Tracy V. Wilson?

  Finlay didn't establish a permanent practice in Cuba right away. He went back to France for a while to continue his education in neurology and ophthalmology. He and his father also went to Peru together, and they practiced medicine there. On October 16, 1865, Carlos married a woman named Adela, who was from Trinidad. They would go on to have three children together: Carlos Eduardo in 1868, Jorge Enrique in 1870, and Jose Maria Francisco in 1876. In 1869, the family went to Trinidad to visit Adela's family. According to Gutierrez's biographical sketch, in 1875, Carlos also went to New York,

• 9:02Tracy V. Wilson?

  quote, "in search of professional advice for Mrs. Finlay", which suggests that she was having a medical issue and that he wanted to consult a specialist. But Gutierrez doesn't suggest what that issue may have been. At the beginning of his medical career, including while he was practicing outside of Cuba, Finlay focused on general medicine along with ophthalmology and eye surgery. But by the 1860s, he was focusing more on diseases that were public health issues in Cuba, including yellow fever, which is a viral hemorrhagic fever. Most people who contract yellow fever have symptoms like fever, chills, body aches, nausea, vomiting, and weakness, and they recover within three or four days.

• 9:47Tracy V. Wilson?

  But about 15% of people who contract yellow fever develop a serious illness that has a much higher fever and organ damage, jaundice, hemorrhaging, and black vomit caused by that hemorrhaging and organ destruction. Still today, as many as 50% of people who develop this more serious version of the disease die within seven to 10 days. Today, we know that yellow fever is spread by mosquitoes, especially Aydes aegypti, which thrives in warm climates and is native to Africa. These mosquitoes were introduced to the Caribbean and the Americas through the transatlantic slave trade. And the first reports of yellow fever

• 10:32Tracy V. Wilson?

  in the Americas were in the 17th century. The disease soon became endemic in tropical areas that had a large enough population for sustained transmission. It also caused huge devastating outbreaks in places outside the tropics as mosquitoes and sick passengers arrived aboard ships. In the United States, there were frequent outbreaks in the South, but they could happen in the North as well. For example, about 10% of the people living in Philadelphia died in the yellow fever outbreak in 1793. Yellow fever also became a particular problem for Spanish colonial authorities and the Spanish military in Cuba.

• 11:16Tracy V. Wilson?

  Spain had claimed Cuba as its territory in 1492 and started establishing settlements there in the 1500s. Cuba's indigenous population included multiple Arawakans-speaking peoples, and they faced displacement, introduced diseases, violence, and genocide. Indigenous people and enslaved Africans rose up against the Spanish in Cuba for decades. And in 1868, an anti-colonial uprising began that came to be known as the 10 Years' War. And this war was interconnected with the movement to abolish slavery. Large numbers of Spanish soldiers were sent to Cuba to put down this uprising. And they were vulnerable, not just to yellow fever,

• 12:00Tracy V. Wilson?

  but to a range of other tropical diseases that their immune systems had no experience with. They were also housed in close quarters, making it easy for infected mosquitoes to bite multiple people. This contributed to the spread of other diseases, including malaria, which is also spread by mosquitoes, and typhus, which is spread by fleas and lice. Serious illnesses became an enormous problem for the Spanish military, with death rates that were much, much higher among soldiers than they were among the civilian Cuban population. That continued to be true after the 10 Years' War ended in 1878, including during the Cuban War of Independence that started in 1895.

• 12:46Tracy V. Wilson?

  More than 90% of the deaths among Spanish troops between 1895 and 1898 were due to disease, not combat injuries. And more than a third of those deaths were from yellow fever. Maximo Gomez Ibáñez, leader of the Cuban Liberation Army during the 10 Years' War and the Cuban War of Independence, described June, July, and August as his best generals. Those were the months when many of these diseases peaked and the months when mosquitoes were most active. But at the time, they didn't know that mosquitoes were spreading the illness. The person who figured out the mosquito part was Carlos Juan Finlay.

• 13:29Tracy V. Wilson?

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• 15:42Tracy V. Wilson?

  We've all done it, tumble down an internet rabbit hole trying to self diagnose. And sometimes doing our own research can leave us more anxious than informed. Your feed is packed with wellness trends telling you to cold plunge, protein max, detox, track your sleep. But what's actually real? What's exaggerated? What's just wrong? That's exactly what Health vs. Hype from the American Medical Association and iHeartMedia's Ruby Studio is here to find out. Each episode, Emmy nominated science communicator Trace Dominguez, who's racked up billions of views across PBS, Discovery Channel, and YouTube, talks to doctors, influencers, and real people trying these trends.

• 16:25Tracy V. Wilson?

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• 16:46Tracy V. Wilson?

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• 17:31Tracy V. Wilson?

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• 17:51Tracy V. Wilson?

  The focus in today's episode is yellow fever. But in addition to his postgraduate training in ophthalmology, Carlos Juan Finlay also studied and wrote on a range of other illnesses that were affecting people in Cuba. One was cholera. In 1867, he suggested that the source of a cholera outbreak was sewage contamination of a water supply. Over the course of his work, he also published papers on tuberculosis, tetanus, leprosy, nutritional diseases like beriberi, and parasitic diseases like trichinosis and phyloriosis. He was writing about yellow fever by 1865. Finlay developed a thorough knowledge

• 18:32Tracy V. Wilson?

  of the late 19th century's medical understanding of yellow fever. He also studied the air in Havana, measuring its alkalinity and cross-referencing that with the seasons, the climate, and public health. He noticed that the air seemed to be more alkaline in times when yellow fever outbreaks peaked, and he thought there might be some kind of connection there. In 1879, after the end of the Ten Years' War, the United States sent a commission of doctors to Cuba to study yellow fever. In the US, interest in the disease was primarily connected to those unpredictable and horrifying outbreaks that struck American cities. A huge outbreak had struck more than 100 cities and towns

• 19:16Tracy V. Wilson?

  in the southern US the year before. Because of his reputation and his previous work on yellow fever, Finlay was appointed to work with the US Commission. They did not pinpoint the cause of yellow fever or correctly identify how it was spread, but this work did connect Finlay to US Army physician and bacteriologist George Miller Sternberg, the commission's microscopist. Finlay and Sternberg became friends, and Sternberg shared his collection of slides containing blood and tissue samples from yellow fever patients with Finlay. The commission's report concluded that the infectious agent that caused yellow fever had to be replicating somewhere outside of human bodies

• 20:00Tracy V. Wilson?

  before it infected them. I could not get my hands on this actual report, but that is how it was characterized in other writing about it. Finley had also learned about a type of corn rust that had to incubate in barberry bushes before it could infect the corn. That combined with his microscopic study of Sternberg's blood and tissue samples, and what the blood cells and vessels looked like in those samples. He started to wonder if yellow fever could be introduced into the body through the bite of an insect. By 1881, Finley was confident that yellow fever was being spread by mosquitoes, specifically the females of the species known as Aedes aegypti today.

• 20:45Tracy V. Wilson?

  It has had multiple other scientific names at various points in the past. So if you do additional reading, you may see that species named differently. But on February 18th of 1881, he presented at the International Sanitary Conference in Washington DC. And he said that he believed an intermediate agent played a role in yellow fever transmission. He said that he was not yet ready to say what that intermediate agent was, but that he was working on a paper about it. This presentation was not received very well. He had been selected to attend this conference without a lot of notice. So he hadn't had time to really do a lot of experiments

• 21:26Tracy V. Wilson?

  to verify what he had concluded based on his observations so far. Even though he was sure that the mosquito was the vector in question, he did not want to make that announcement without evidence to support it. Nobody from the audience asked him any questions about his presentation. But apparently, somebody did tell him that he needed to follow Robert Koch's postulates, including isolating the organism in question, culturing it, and confirming that it caused disease in a healthy subject.

• 22:01Tracy V. Wilson?

  This would have been impossible at the time. Koch's postulates were developed through study of bacterial illnesses like anthrax and tuberculosis, which could be filtered, cultured, and observed through a microscope. Yellow fever is caused by a virus, and viruses could not be filtered, cultured, or seen using the technologies that were in existence at the time. People did not yet know that viruses existed. On August 14, 1881, Finlay delivered a paper titled "The Mosquito", hypothetically considered as the transmitting agent of yellow fever, before the Havana Academy of Sciences.

• 22:41Tracy V. Wilson?

  In it, he referenced Sternberg's tissue samples, quote, "showing what, to me, appeared to be a most striking feature, namely that the red blood globules are discharged unbroken in the hemorrhages of yellow fever. This fact, taken in connection with the circumstance that those hemorrhages are often unattended with any perceptible break in the blood vessels, while, on the other hand, they constitute a most essential clinical symptom of the disease, led me to infer that the principal lesion of yellow fever should be sought for in the vascular endothelium. The disease is transmissible.

• 23:21Tracy V. Wilson?

  It attacks but once the same person, and always presents, in its phenomena, a regular order comparable with that observed in the eruptive fevers, all of which circumstances suggested to my mind the hypothesis that yellow fever should be considered as a sort of eruptive fever, in which the seat of the eruption is the vascular endothelium." He walked through what was needed for yellow fever to be transmitted. Quote, "One, the existence of a yellow fever patient into whose capillaries the mosquito is able to drive its sting and to impregnate it with the virulent particles at an appropriate stage of the disease.

• 24:03Tracy V. Wilson?

  Two, that the life of the mosquito be spared after its bite upon the patient until it has a chance of biting the person in whom the disease is to be reproduced. Three, the coincidence that some of the persons whom the same mosquito happens to bite thereafter shall be susceptible of contracting the disease."

• 24:23Tracy V. Wilson?

  He also explained the mosquito's physiology and behavior and how they facilitated the spread of yellow fever. He described the experiments that he had conducted in which he allowed a mosquito to bite a yellow fever patient and then later bite someone who had never had yellow fever. This seemed to lead to mild cases of yellow fever and several of his test subjects were diagnosed with, quote, "abortive yellow fever." But most of his test subjects didn't develop any kind of symptoms. "Barring my first three inoculated men, no other case of confirmed or abortive yellow fever has occurred among the 20 non-immunes whom I have had under observation."

• 25:06Tracy V. Wilson?

  He also very clearly understood that his conclusions would be controversial. He wrote, "I understand but too well that nothing less than an absolutely incontrovertible demonstration will be required before the generality of my colleagues accept a theory so entirely at variance with the ideas which have until now prevailed about yellow fever." The prevailing idea about yellow fever at this point was that it was spread through fomites, that is inanimate objects or materials that could carry infectious agents. And when it came to yellow fever, especially severe hemorrhagic cases of yellow fever, this idea made so much sense.

• 25:47Tracy V. Wilson?

  Since yellow fever is a hemorrhagic disease, patients bled and they vomited. Their linens, the medical equipment, and the rooms where they were being treated became soiled and the nature of that contamination was just viscerally horrifying. So a big part of attempts to control the spread of yellow fever was relentless, aggressive cleaning and disinfection of those spaces.

• 26:13Tracy V. Wilson?

  So Finlay's hypothesis about mosquitoes wasn't just going against the prevailing medical knowledge about yellow fever. If he was correct, it also meant that the one thing people felt like they could do to control yellow fever was wrong, and all the time and money and effort that had been spent on disinfecting linens and scrubbing hospital walls and floors had been essentially useless. In 1881, there was also only one other disease that had been identified as being spread by insects, a parasitic infection called filariasis, although the transmission of that was not fully understood until 1901. People just did not think of insect-borne diseases as a real possibility.

• 26:59Tracy V. Wilson?

  So Finlay's conclusions were not just dismissed, they were ridiculed. People started calling him "the mosquito man." Other researchers in Cuba excluded him from their work. That included Juan Santos Fernandez, who established and funded a histobacteriological laboratory and institute of rabies vaccination in 1885. In addition to dismissing Finlay's work, Santos Fernandez hired Diego Tamaio, who was another vocal critic of Finlay's, to head up that institute's yellow fever research. This dismissal and derision continued after Finlay did more research and published "Yellow Fever: Its Transmission by Means of

• 27:42Tracy V. Wilson?

  the Culex Mosquito" in the American Journal of the Medical Sciences in 1886. This was obviously both personally and professionally crushing. It shook Finlay's faith in the broader scientific and medical community. It was true that his conclusions had come from his observations and limited experiments on volunteers, not through rigorous controlled studies or following Koch's postulates. But he was also confident that his conclusions were correct and that they were worth examining further. Finlay's wife was a big source of support. Another was Claudio Delgado, a doctor from Spain who was Finlay's friend and colleague and continued to work with him through all

• 28:26Tracy V. Wilson?

  of this. They lobbied for the establishment of another bacteriological research facility dedicated specifically to finding the cause of yellow fever. Again, viruses still had not been discovered yet, which is why their focus was still on bacteria. Their efforts to establish a new research center were unsuccessful, but Finlay continued to gather supporting evidence for his hypothesis through 102 experiments on human volunteers. Most of them were new arrivals to Cuba, including soldiers and Catholic clergy. He had the cooperation of Jesuit and Carmelite fathers working in Cuba, and of Captain General Ramon Blanco, who was a brigadier general and colonial administrator.

• 29:11Tracy V. Wilson?

  A lot of writing about this research, including the way we described it in our episode on Walter Reed, misses something really important. Finlay is characterized as not understanding that it takes roughly two weeks for the yellow fever virus to replicate in a mosquito's body before it can cause serious illness, and that's why most of his experiments did not result in patients who had full-blown yellow fever. This is presented as a reason why people were not taking him seriously. He was waiting only long enough for the mosquito to digest the infected blood it had consumed, then to be hungry again. This only took about four days, so his experimental subjects typically did not get

• 29:54Tracy V. Wilson?

  very sick if they showed any symptoms at all. But he was not trying to give people full-blown yellow fever. He was using these mosquito bites as an inoculation, much like intentionally exposing someone to cowpox, which is a mild disease, to make them immune to smallpox. And his test subjects did seem to have resistance to yellow fever after being bitten. In 1891, Finlay published "Inoculations for Yellow Fever by Means of Contaminated Mosquitoes" in the American Journal of the Medical Sciences. In this paper, he rebutted some of the criticism

• 30:34Tracy V. Wilson?

  of his earlier work, and he also presented the results of a study of 67 volunteers who were monitored for three or more years after being bitten by a mosquito that was infected with yellow fever. During that three-year period, they lived in parts of central Havana where there were frequent yellow fever outbreaks. This observation was still ongoing, so 15 of them hadn't gotten to that three-year mark yet, but they also had not had any indication of contracting yellow fever. 12 had developed a fever within 25 days of being bitten by the mosquito, and they either had or had not had albumin in their urine, which is a sign of yellow fever.

• 31:17Tracy V. Wilson?

  12 of them had no symptoms at all after being bitten, and also no other yellow fever symptoms in the three years since then. 24 of them had no symptoms after being bitten, and then had a mild fever sometime in the three years afterward, but no other sign of yellow fever beyond that. Three had no symptoms after being bitten, and then later got yellow fever but recovered. And then one had no symptoms after being bitten, but then later on got yellow fever and died. Outsiders who came to Cuba were described as acclimated once they no longer seemed susceptible to the tropical diseases that were endemic there. Usually, that happened after repeated illnesses,

• 32:02Tracy V. Wilson?

  at least some of them serious. By Finlay's calculations, 92.2% of these test subjects were acclimated to yellow fever by being bitten by a mosquito in this experiment, having at most very mild symptoms. That acclimation was the goal, not a full-blown case of a potentially deadly disease. We'll talk about how Walter Reed wound up being given a lot of the credit for the discovery that mosquitoes spread yellow fever after a sponsor break.

• 32:37Tracy V. Wilson?

  We've all done it, tumble down an internet rabbit hole trying to self-diagnose. And sometimes doing our own research can leave us more anxious than informed. Your feed is packed with wellness trends telling you to cold plunge, protein max, detox, track your sleep. But what's actually real? What's exaggerated? What's just wrong? That's exactly what Health vs. Hype from the American Medical Association and iHeartMedia's Ruby Studio is here to find out. Each episode, Emmy-nominated science communicator Trace Dominguez, who's racked up billions of views across PBS, Discovery Channel, and YouTube, talks to Doc Influencers and real people trying these trends.

• 33:19Tracy V. Wilson?

  Not to cancel them, not to hype them more, but to actually understand them. Because when it comes to your health, who you listen to matters. Start asking better questions and listen to Health Versus Hype on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

• 33:40Tracy V. Wilson?

  Guess who's back in the house? The old gays return for season two of Silver Linings, their hit podcast from iHeart's Ruby Studio in partnership with ViiV Healthcare. Just wait until you hear what hosts Robert McMillan and Jess A. have in store this time around. They strut back down memory lane navigating life, love, loss, and everything that shaped them along the way. And as usual, someone just might break into song. From leather bars to bathhouses, dance floors to drag brunch, nothing stays off limits. These are the kinds of insights that can only come from experience. So listen to your elders, honey, and discover the silver linings you can take with you. All sass, zero filter, and decades of perspective from four friends proving that queer joy

• 34:25Tracy V. Wilson?

  only gets better with age on the podcast that never gets old. Listen to Silver Linings, available on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

• 34:39Speaker 06

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• 36:51Tracy V. Wilson?

  In 1893, Carlos Juan Finlay and Claudio Delgado started collaborating with some of the researchers from Juan Santos Fernandez's institute. At that point, Diego Tamaio had resigned, and while Santos Fernandez was not a believer in Finlay's ideas, there were less objections to working with him. That continued until 1895 with the start of the Cuban War of Independence. Medical and scientific research really struggled during the war. In addition to the typical risks and hardships of war, a lot of Cuban doctors and researchers started leaving for the United States.

• 37:34Tracy V. Wilson?

  The US became directly involved in this war between Cuba and Spain in 1898, after Congress issued resolutions supporting Cuban independence and demanded a withdrawal of Spanish troops. Spain declared war on the US, which then declared war on Spain, and from the US point of view, this part of it is known as the Spanish-American War. Finlay was in Tampa, Florida, when the US declared war on Spain, and he traveled to Washington DC to volunteer his service as a surgeon. He was sent back to Cuba aboard a hospital ship. He was 64 at this point. The Spanish-American War ended with a treaty signed in Paris on December 10, 1898.

• 38:18Tracy V. Wilson?

  Under this treaty, Spain ceded the islands of Guam and Puerto Rico to the United States, and the US purchased the Philippines from Spain for $20 million. This treaty also guaranteed Cuba's independence, with the United States temporarily occupying Cuba and establishing a military government. The US occupation lasted from the end of the war until Cuba became formally independent in 1902. George Miller Sternberg, the microscopist who had become Finlay's friend and colleague back in 1879, was now the Surgeon General of the Army, and the US Army faced the exact same issues with yellow fever and other tropical diseases as the Spanish Army had.

• 39:03Tracy V. Wilson?

  US soldiers arrived in Cuba and quickly got sick with one disease after another, with diseases becoming a much bigger issue for soldiers than combat. The same was true on the other islands that the US had acquired from Spain and was now occupying, so there was a big focus on finding out how to prevent and treat yellow fever and other tropical diseases.

• 39:27Tracy V. Wilson?

  By this point, there was a little less resistance to the idea that a disease could be spread through these kinds of bites. Ticks, which are arachnids, were identified as the vector in Texas cattle fever in 1890. Mosquitoes were identified as transmitting malaria in 1897. So when the US Army Yellow Fever Board visited Cuba in 1900, mosquitoes did not seem quite as far-fetched as a vector of the disease. This was not the first commission the United States sent to Cuba for this kind of research. We talked about the one in 1879, and then there had been other ones in between.

• 40:08Tracy V. Wilson?

  But this is the one that Army physician Walter Reed was part of, and it's so associated with him that sometimes it is called the Reed Commission. Reed and his team eventually visited Finlay. They used mosquito eggs that he had collected and did experiments that were very similar to his own, putting a mosquito in a test tube and then putting the mouth of that tube against the skin of someone who had yellow fever. Once the mosquito fed on that person, they would wait until it had digested its meal and then have it bite someone else. I will confess that this all puts a cartoon in my head, the idea of waiting for a mosquito to digest things, like, "Did you enjoy your soup, sir?"

• 40:51Tracy V. Wilson?

  A member of this commission named James Carroll participated in one of these experiments, contracted yellow fever and recovered. Another, Jesse Lazir, was apparently bitten by a mosquito in the lab, not part of this controlled experiment, just a mosquito that was flying around in a building that also housed yellow fever patients. He contracted yellow fever and unfortunately died. Based on the commission's research in Cuba, Reed announced that mosquitoes had been conclusively determined to be the vector for yellow fever on October 23, 1900.

• 41:27Tracy V. Wilson?

  Reed's commission is sometimes also credited with figuring out the amount of time required for a mosquito to be able to infect someone with a serious case of yellow fever called the extrinsic incubation period. That, however, was discovered by Henry Rose Carter in experiments carried out in Mississippi in 1898. Carter did not publish this work until 1900, though. And one of the sources used in this episode also said that Finlay already understood this part of it as well. When Reed announced and wrote about this work, he made some references to Finlay, including at one point saying, quote, "It was Finlay's theory and he deserves much for having suggested it."

• 42:13Tracy V. Wilson?

  William Crawford Gorgas, who would later become Surgeon General of the US Army and was in charge of sanitation during the building of the Panama Canal, called Finlay's reasoning behind identifying the mosquito as the, quote, "best piece of logical reasoning that can be found in medicine anywhere," and also described the US as owing a great debt to Finlay. But Finlay really didn't get much formal recognition in the US. There was a much bigger focus on Walter Reed. There was also a big focus on how this discovery was connected to the military and military readiness. In 1900, US Army General Leonard Wood, who was a physician and military governor of Cuba, said, quote, "The confirmation of the doctrine of Dr.

• 42:57Tracy V. Wilson?

  Finlay is the biggest step that has been given in medical science after the discovery of Jenner's vaccine, and this single fact is enough to justify the war against Spain." That recognition of Finlay did not carry throughout the Army. At the Pan American Medical Congress in February of 1901, the American Army Board gave a presentation that made this discovery sound like it was Walter Reed's work that happened at a session Finlay was presiding over. Cuban delegates to this Congress were absolutely furious. But Finlay got more recognition in Europe, and in Cuba, he became a national hero.

• 43:40Tracy V. Wilson?

  He was appointed Chief Sanitary Officer of Cuba after Cuba became formally independent in 1902.

• 43:48Tracy V. Wilson?

  This work included mosquito control and eradication programs, something that had started all across areas that were affected by yellow fever as soon as Reed made this announcement. These efforts led to yellow fever being eradicated in the southern United States and in a number of tropical cities and towns. Although these mosquito control efforts involved the use of insecticides that did not target only mosquitoes, they killed other insects as well. And the insecticides also had other health effects of their own. Finley continued to work on matters of public health in Cuba, including an anti-infantile tetanus campaign. This included research carried out in 1903,

• 44:31Tracy V. Wilson?

  which showed that wicks that were being used to tie off the umbilical cords of newborns provided a favorable medium for tetanus to grow. Finley developed a program for distributing aseptic packages for treating the umbilical cord to poor parts of Cuba, and that led to a steep drop in infantile tetanus rates. Finley retired in 1909. In 1911, The New York Times published a piece titled, "Dr. Finley Gets Full Credit Now: Havana Physician Who Solved the Yellow Fever Problem Is Extolled Here and Abroad." Using the name Charles, which Finley did use himself in work that was published in English,

• 45:13Tracy V. Wilson?

  it described his research prior to the arrival of the Reed Commission. And it summarized a paper written by a doctor from Edinburgh, who wrote in part, quote, "Considering the times, it will eventually be considered one of the most wonderful pieces of constructive work in the history of medicine. But like every other advance, it was rejected by contemporaries. Unlike nearly all other great medical discoverers, however, he has lived to see the acceptance of his facts and has not had to die of a broken heart. But it has been enough to break anyone's heart to see himself so utterly ignored while the world has been singing the praises of the men upon whom he forced his ideas."

• 45:56Tracy V. Wilson?

  Carlos Juan Finlay died on August 20th, 1915, at the age of 82. He had written 40 articles on yellow fever over the course of his career, and many, many other articles on other diseases and conditions. Over the course of his life, he was nominated for the Nobel Prize in Physiology or Medicine seven times, but he was never awarded it. He was briefly acknowledged when Max Styler was awarded the Nobel Prize in 1951 for his discoveries concerning yellow fever and how to combat it. Those discoveries included an attenuated form of the virus that could be used as a vaccine.

• 46:38Tracy V. Wilson?

  Part of the presentation speech said, quote, "As early as the 18th century, the abundance of mosquitoes in places where the disease occurred has been observed." And in 1881, Dr. Carlos Finlay, a Cuban physician in Havana, had written a treatise in which he asserted that the disease was transmitted by mosquitoes, but his assertion drew little attention. As we said earlier, Finlay became a national hero in Cuba. He was honored with postage stamps and street names. The Finlay Institute for Investigations in Tropical Medicine was established in his honor after his death. In 2013, he was also honored with a googledoodle for his 180th birthday.

• 47:23Tracy V. Wilson?

  Yellow fever, of course, still exists today. Researchers started discovering viruses and differentiating them from bacteria and toxins at the very end of the 19th and early 20th centuries. The yellow fever virus was isolated for the first time during a massive outbreak in Africa in 1927. Today, the World Health Organization lists 27 countries in Africa and 13 in Latin America as at high risk for yellow fever outbreaks. Protection from mosquito bites, eliminating stagnant water, and mosquito eradication programs can all reduce the risk of yellow fever outbreaks and outbreaks of other mosquito-borne diseases.

• 48:06Tracy V. Wilson?

  But the disease cannot be eliminated entirely. In addition to Aedes aegypti, which lives in urban areas, it can also be carried by other mosquitoes that live in the jungle and feed primarily on monkeys. So there's ongoing circulation of the disease in jungle environments, which can then be carried back to human settlements when people get bitten in the jungle and then return home. Yellow fever is vaccine-preventable today. And while there are some antiviral treatments that are used on occasion, there's no specific yellow fever antiviral. Most people who contract it receive supportive care. So that's Carlos Juan Finlay. Finally, after many years of wanting to do this episode.

• 48:51Tracy V. Wilson?

  Do you have listener mail? I wanted to say listener mail that you've been waiting to read for several years, but I know that's not true. No, I mean, I could try to look for some from way, way in the past, but I won't. Rather than reading a specific mail, I wanted to talk generally about the theme of some email because when we did our episode on Bhagat Singh Thin, we talked about how to pronounce the religion Sikh and how there are people who pronounce it Sikh. And we have gotten some feedback from folks whose relatives who immigrated from India do pronounce it Sikh. So I wanted to talk a little bit more about that.

• 49:31Tracy V. Wilson?

  The people that I listened to on how to pronounce this name are themselves Sikh. Some of them are Sikh from India or somewhere else in the Indian subcontinent or immigrants to the United States who are Sikh. And they were pretty specifically adamant that Sikh is the correct pronunciation. Although, as we said, there like, there's some nuance in how to pronounce it with that vowel sound that I cannot hear the difference in how it's being said. That said, the pronunciation of Sikh was incredibly widespread here in the US,

• 50:11Tracy V. Wilson?

  incredibly widespread in former British territory and what's now like India and Pakistan and Bangladesh and all of that. And so the way it's really been characterized is the pronunciation of Sikh being a pronunciation that evolved because of British colonization of that part of the world. And that the pronunciation of Sikh is like reclaiming the correct pronunciation from one that had been Anglicized many years ago. Absolutely unsurprising that people's maybe older relatives, maybe people who came to the United States a long time ago, might be using the pronunciation Sikh and that might sound correct to them

• 50:53Tracy V. Wilson?

  because that's the one that they grew up with and have always used. But a lot of people have talked about trying to reclaim the pronunciation of Sikh as the correct pronunciation now today. So yeah, I think Holly and I, when you and I were talking about it, we both had always heard the pronunciation Sikh from earlier in our lives. Yeah. And all of that. So I just wanted to give a little more context to that after getting some email about it. If you would like to send us an email about anything, we're at [email protected]. And if you want to find the show notes to this episode with all of our research that we used, it is at our website, which is at

• 51:38Tracy V. Wilson?

  missedinhistory.com. And you can subscribe to the show on the iHeartRadio app and anywhere else you'd like to get your podcasts.

• 51:51Tracy V. Wilson?

  Stuff You Missed in History Class is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.

• 52:06Tracy V. Wilson?

  Whether you're calling the wise women in your life, video calling your girlfriends across the country, or checking in on someone who always knows how to make you smile, staying connected matters. Those small conversations, shared laughs and quick hellos are what keep relationships strong even when life gets busy. Some of the most life-giving conversations start with just a phone call. That's why AT&T guarantees the network you can rely on so you can focus on the moments and people that matter most. That's the AT&T Guarantee. AT&T: Connecting Changes Everything. Terms and conditions apply. Visit att.com/guarantee for details. A rare disease diagnosis can change your life, but it doesn't have to define your future. In season seven of Untold Stories: Life with a Severe Autoimmune Condition,

• 52:50Tracy V. Wilson?

  host Martine Hackett continues the conversation with people living with MG, CIDP, and the broader rare disease community, exploring what comes after diagnosis through stories of hope, progress, and connection. Produced by Ruby Studio in partnership with Argenx. Listen on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

• 53:14Tracy V. Wilson?

  Livrite, publishers of John U. Bacon's New York Times bestseller, The Gales of November: A Chronicle of the S.S. Edmund Fitzgerald's 1975 Shipwreck. "Never has it been told better than by Mr. Bacon in this colorful book," writes John J. Miller of The Wall Street Journal, while author Hampton Sides proclaims that it's destined to be a classic. The Gales of November, now in paperback.

• 53:42Tracy V. Wilson?

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• 54:12Speaker 00

  This is an iHeart Podcast. Guaranteed Human.