Aarati Asundi (00:12) Hi, everyone, and welcome back to the Smart Tea Podcast, where we talk about the lives of scientists and innovators who shape the world. I'm Aarati. Jyoti Asundi (00:21) Her mom Jyoti. Aarati Asundi (00:22) How have you been doing, Mom? Jyoti Asundi (00:24) I'm doing okay. Aarati Asundi (00:26) Yeah, just keeping busy? Jyoti Asundi (00:27) Keeping super busy but being busy is good because I think I would make an utter nuisance of myself to my entire family if I did not have something me busy legitimately. Aarati Asundi (00:40) Keep your brain occupied. Jyoti Asundi (00:41) I'm super grateful to have a lot of things keeping me busy because that allows me to hold my family close to me without annoying them. Aarati Asundi (00:51) Aww you're never annoying. But that's a great segue actually, because we will be talking about something very annoying. The mosquito, probably the most annoying on the planet that I can think of. Jyoti Asundi (01:05) Absolutely. Especially since I grew up in a tropical setting, you know? You tell me mosquito and I have three or four stories to tell right off the bat. So let's not go there because the whole story will come about something else. Aarati Asundi (01:21) Yes, highly irritating insect. But the reason that I decided on this story was I feel like we've been doing a lot of non bio people and I just wanted to go back to the roots. I've been super, super busy also and I was just like, I can't handle another physics story or something. And I know that I don't do them that often, but it takes a lot out of me. So yes. Jyoti Asundi (01:45) Yes, yes, yeah, because you're moving away from your comfort. And that's always a challenge. Aarati Asundi (01:50) And it's super interesting. It's super interesting. And I love like, once I figure it out, I love it. And I'm like, this is so fascinating, but man, it takes a lot of research. So I was like... Jyoti Asundi (02:01) Yeah. Stepping out of your comfort zone is very good for your brain. And it actually- it's very good to keep away diseases like Parkinson's and Alzheimer's and things like that. And also to just keep that cognitive function going. But then at some point you have to give that poor brain a rest also and say, let me just go back to my comfort zone, please. Chicken soup for the soul this time, please. Aarati Asundi (02:25) Exactly. And so that's what this story is. This is me going right back into my little comfort zone... Jyoti Asundi (02:31) Absolutely. Aarati Asundi (02:31) ...of biology and like basic things that we know and take for granted today and how did we figure it out. And so I have a list of scientists that I would like to do for this podcast and as I was going through that list, I came across the name Carlos Finlay, helped discover that the mosquito was the vector for yellow fever. Jyoti Asundi (02:56) Oh interesting, okay got it. It's a vector for malaria we know that. Aarati Asundi (03:01) We didn't know that at the time. So he's the first... Jyoti Asundi (03:03) Not at the time of yellow fever? Aarati Asundi (03:05) Correct. So he's the first one to figure out that mosquitoes could be a vector for disease in general. Jyoti Asundi (03:12) In general, oh I see. Aarati Asundi (03:13) That any insect, yeah, that any insect... Jyoti Asundi (03:15) Oh any insect! He is the first one to come up with that concept absolutely. Aarati Asundi (03:20) I think people were like, in general, probably bugs are dirty and we should stay away from them. But he's the first one to actually connect that this mosquito is a vector for this disease. Jyoti Asundi (03:31) Yeah, I get it. And because my brain is running in different directions, yellow fever is not the same as jaundice, correct? Or is it? Aarati Asundi (03:40) No, it is not the same as jaundice, but jaundice is one of the symptoms of yellow fever. And so that's why one of the reasons it's called yellow fever. Jyoti Asundi (03:50) Got it. Okay. Okay. Thank you. Aarati Asundi (03:52) So we're talking about Carlos Finlay. And actually, his story is very interesting because I hadn't actually heard his name before or it didn't ring a bell. But then other people in his story did ring a bell. And so it's very interesting that I'm like, how come we don't hear his name, but we hear some of the other names? So we're going to get into that a bit. Jyoti Asundi (04:12) I see. Sounds good. Aarati Asundi (04:15) So we'll start with his childhood. Actually, we're going to start a little bit with his parents because his parents have a very backstory as well. So Carlos was born on December 3rd, 1833 as Juan Carlos Finlay y de Barrés in Cuba. His mother, Eliza Barrés, was French and his father, Edward Finlay, was Scottish. So Edward had a surprisingly interesting backstory. Back in the 1820s, Spain was in a weakened and somewhat chaotic state after the Napoleonic Wars And so Spain was trying to rebuild. But England, which had actually been Spain's ally against Napoleon, realized that having Spain in this weakened state was actually very beneficial for them. They were able to trade a little bit more freely, get access to a couple more places. And so although they weren't going to outright declare war on Spain, England would quietly and indirectly try to keep Spain down whenever they could. And so around this time, there is a military general in Venezuela named Simón Bolívar, who was organizing revolutions to win back Venezuela's independence from Spain. Jyoti Asundi (05:37) Okay. Aarati Asundi (05:39) And in 1821, he led the battle of Carabobo against Spain's Royal Forces and England sent so-called volunteers to help Simón Bolívar because again it's not like a military action that's official or anything. Jyoti Asundi (05:57) Correct. Aarati Asundi (05:58) Because they're not declaring war they're not officially taking sides. Jyoti Asundi (06:01) They are being frenemies. Aarati Asundi (06:03) Basically. Jyoti Asundi (06:04) Backstabbing them. Okay. Aarati Asundi (06:06) Yeah. And so England sends help to Simon Bolivar in Venezuela against the Spanish Royal Forces because if Venezuela was freed, then England would be more easily able to trade So Edward Finlay is this young man. He's barely gotten out of college at the University of Edinburgh, and he gets on a ship to sail to Venezuela to help. Jyoti Asundi (06:30) As a volunteer soldier. Aarati Asundi (06:32) Correct. However, during this journey, the ship was caught in a hurricane and capsized and Edward barely survived and he ended up in Trinidad. There he set up a hospital and he got married to Eliza. And then after the marriage, Edward and Eliza moved to Cuba. And so he went to the University of Havana and he got his medical degree in Cuba. And with that, they bought a coffee plantation. They set up their home and yeah. Jyoti Asundi (07:05) From a shipwreck to become a medical student, then to a doctor, to a plantation owner, to a founder of a hospital, that's a very strong upward trajectory that he followed. Okay. Aarati Asundi (07:17) Yeah. And Juan Carlos is born there. So given that he had a Scottish father and a French mother, I kind of wondered how he ended up with such a Spanish-sounding name. But apparently, Edward and Eliza also started going by Eduardo and Isabel to assimilate into the Cuban culture. Jyoti Asundi (07:36) Yes that makes sense. They probably loved the place that they were in. Aarati Asundi (07:40) I mean what's not to love? It was probably beautiful tropical, you know? Jyoti Asundi (07:44) Beautiful, a beautiful tropical paradise. Aarati Asundi (07:46) And Cuba at this time was such a hub for European countries and Americans and everything. There's so much trading happening there. There's so many cultures that are all meeting and mingling in Cuba. So a really great place to be. A lot of economic opportunities, a lot of opportunities for doctors. So what's not to love? Jyoti Asundi (08:09) Yeah, so it's their adopted mother. They have embraced Cuba wholeheartedly. Aarati Asundi (08:14) Yeah. So ⁓ it was a great place to grow up. Juan Carlos grew up on the plantation, and he was homeschooled by his aunt Anna, who is Edward's sister, who moved from Edinburgh to come live with them. Growing up on the plantation was a wonderful way for Carlos to be introduced to nature. Again, tropical climate, biodiversity, and any adventurous kid would have loved roaming around the plantation, looking at all the plants and bugs and birds and whatnot are native to that area. Jyoti Asundi (08:46) Yeah. Aarati Asundi (08:48) In 1844, when he was 11, Juan Carlos was sent to France to get a European education. But here's where his problems start. When he was in France, he was stricken with a severe case of chorea, which is involuntary muscle movements. Jyoti Asundi (09:05) Oh, I see. Aarati Asundi (09:07) Have you heard of chorea? Jyoti Asundi (09:09) No, I almost wanted to suggest that it might be cholera, but obviously it's not. Aarati Asundi (09:14) Well, it's interesting you say that because a lot the sources that I was reading, like half of them said he was stricken with cholera and half of said he was stricken with chorea. And it's very similar spelling. It's C-H-O-R-E-A. So I was doing a lot of work to figure out which one it was. Jyoti Asundi (09:33) Which of these is it and are they distinct from each other yeah? Aarati Asundi (09:37) So I'm still not sure, but I think chorea is probably more correct because, like I said, it's involuntary muscle movements and Juan Carlos's speech was deeply affected by this disease. And I was like, think cholera probably doesn't affect your speech. Jyoti Asundi (09:58) Cholera is a water-borne disease and I think it affects the gut system, the digestive system. Aarati Asundi (10:03) Yes, it does. It does. Jyoti Asundi (10:04) Yes. So yeah. Aarati Asundi (10:05) I was like, you know, maybe if you lost enough fluid and your electrolytes got imbalanced enough, it could affect something. But I think chorea is more likely. Jyoti Asundi (10:13) No, that's a very specious argument because at the end of the day, every disease, if you lose enough, then you're all going to be dead. So you can call them all the same. No, no, no, no, Okay. So this is chorea which causes... Aarati Asundi (10:26) I'm pretty sure it was chorea. Jyoti Asundi (10:28) ...muscle problems, speech issues. Aarati Asundi (10:32) Yes. And it can be a symptom of many different things like genetic disorders, autoimmune conditions, endocrine or metabolic conditions. So I'm not really sure what caused it in Juan Carlos, but either way, you know, his speech got affected and he couldn't talk. So he got sent back to Cuba to recover. And his father helped him get better with speech therapy and medicine and everything, because his father's a doctor. he eventually did recover but despite this, he had a slight stutter and was slow when he talked for the rest of his life. So after recovering, he was sent back to Europe to continue his education. But it's now 1848, and yet another revolution is brewing in France. I don't think I realized how turbulent the 1800s were for France. They're just one revolution after the other. So it was determined that it wasn't really safe for Juan Carlos to go back to France. So instead, he bounced around Europe for a few years. He spent some time in London and then one year in Germany, where he completed his high school education. And then by then, France had calmed down a bit. So he went back to France to enroll in college in Rouen. But shortly afterwards, he fell sick again, this time with typhoid fever. Jyoti Asundi (11:50) I lost a grandfather to typhoid. Aarati Asundi (11:53) I didn't know that. Jyoti Asundi (11:54) Yeah, my dad's dad. And it's one of those where the entire family falls sick. And then I think they just kind of try to take care of each other. And then there's a relapse. He recovered from his initial bout, but then he had a relapse and died. Yeah, it's those are those are tough ones, because you need so much care and nutrition rest when you are hit with these kind of extremely debilitating conditions and poor nutrition underlies everything so it's very hard. Aarati Asundi (12:27) Yeah. Luckily, I mean, Carlos was a young man when he got it. But again, it was bad enough that he had to leave his education and go back to Cuba to recover. Around this time, he switches his name around to Carlos Juan Finlay because many Europeans apparently had been writing Carlos as his first name on documents. And the mistake happened so often that I think he just figured it'll make life easier. Jyoti Asundi (12:53) I can't fix everybody, This is an easier fix. Yeah makes sense. Aarati Asundi (12:55) Yeah. So he started by going by Carlos rather than Juan. So back in Cuba, Carlos wanted to pursue his medical degree. And so he tried to enroll in the University of Havana right there in Cuba. But the university required you to have a bachelor's degree before entering medical school. And since he had gotten his education kind of all over Europe and then he had to leave early due to getting typhoid fever, he hadn't officially gotten a bachelor's degree. Jyoti Asundi (13:25) Yeah. Aarati Asundi (13:26) And the University of Havana didn't recognize the European course credits. So instead, he cast a further net and he landed on the Jefferson Medical College in Philadelphia, which apparently didn't require him to have a bachelor's. Jyoti Asundi (13:42) Yes, all right. Aarati Asundi (13:44) Different times. Very different times. Jyoti Asundi (13:45) Yeah, I think maybe in those days the education in Havana was superior to... and their standards were higher? Aarati Asundi (13:53) Yeah, I think it was actually. I was reading about that and they were like, those American colleges, they're not as great as ours. Jyoti Asundi (13:59) Yeah, because they are just starting out. They've managed to cast off the yoke of the British dominance. And then they just establishing themselves as an independent country. There's hardly how many states at that time. I don't know. I don't even know if the West was just starting out in California. Philadelphia was one of the older ones. I can see that at very different times. Aarati Asundi (14:22) So he goes to Jefferson Medical College. And he makes good friends with one of his professors, John Kearsly Mitchell and his son Silas. Both of them were distinguished academics and strong proponents of germ theory. Jyoti Asundi (14:38) Hmm. This is coming from Louis Pasteur. Aarati Asundi (14:41) Not yet. This is a few years before Louis Pasteur and Robert Koch actually. So right now we're still in this time where scientists are divided and some people are in the germ theory camp and some people are still in the miasma camp where they that disease is spread through foul odors in the air. And so when someone gets sick and their wounds start festering or something, that enters the air and the bad air is breathed in by somebody who's healthy and then they fall sick. And so this like noxious air theory and germ theory are two different camps right now. Yes. Jyoti Asundi (15:25) Opposing camps. Correct. Okay. Aarati Asundi (15:26) Yes. And so the Mitchells are in the germ theory camp. And so they are believing that they're small microorganisms that exist independently of our bodies and they can come in, contaminate our environment and cause us to become sick. And the reason that they believe this is because they were observing that certain diseases, especially tropical ones, had kind of a weird way of spreading. Malaria and yellow fever, especially, seemed to affect people at random. So one person in the household or on a ship, for example, might fall sick, but then other people around them stayed healthy. And so the Mitchell's were like, in that case, a microorganism would make more sense because if a sick person is sitting in your house and exuding noxious bad air, then everyone in the household should fall sick. Or one sailor on a ship is sick, then every sailor should fall sick, if the miasma theory is correct. Jyoti Asundi (16:29) Correct. Aarati Asundi (16:30) But that's not the case. And so it makes more sense that this one person in the household has either eaten or come into contact with microorganism and they fell sick, but that microorganism is staying within their body. They're not somehow passing it on to the other people in their household in the case of malaria and yellow fever. And so Carlos also starts to think about this idea. So Carlos graduated from medical school in March, 1855. And although the Mitchells wanted him to stay and they were like, you know, there's this really big Spanish population right here in Philadelphia, or you could go to New York, there's, you know, a lot of Spanish speaking people there. You could do a lot to help them. And he knew he could earn a really great living as a physician in the U.S. Carlos's heart was really back in Cuba. So he went back and he took the exam to have his medical degree recognized so he could start practicing medicine in Cuba. But unfortunately, he failed on the partly because his medical training had been in English and not Spanish. And so translating the knowledge... Jyoti Asundi (17:40) Look at the time how times flip around again. Yeah, nowadays there are people the United States who are upset when somebody refuses to speak English or even they hear them speak to each other in Spanish. But at that time, if you spoke only English in Havana, and not Spanish, then you had to work harder to establish yourself. Aarati Asundi (18:04) Yeah, and I think the fact that it's like he's learned all these medical terms in English. You know, because he's fluent in Spanish. He grew up in Cuba so he knows Spanish. But yeah, the fact that his like medical training was in English and he knows all these like medical terms and technical terms in English. And now he has to like translate that into Spanish to take this exam was very hard for him. And again, also, like we were saying, American schools were not highly regarded. And so again, Cuba's, like we don't have an incentive to like... Jyoti Asundi (18:35) This is so funny. This really, the whole setup feels like a social experiment to me, where everything is inverted. American universities are not so great. Coming back with an English education, you're not so great. You need to prove yourself again in this dominant language of choice, which is Spanish. ⁓ So it's funny. I'm just chuckling to myself as I hear the story. Aarati Asundi (18:58) Yeah, no, was when I was researching that too, it was kind of like my mind was bending. It was like, wait a minute, American universities were regarded, people were not impressed that he had learned all this in English and he was failing it in Spanish. And then again, also, he had that speech impediment, so that probably didn't help him at all. Jyoti Asundi (19:19) Yes. Aarati Asundi (19:19) So yeah, he failed the first time around. And so and his father took a break. They went traveling to Peru where he could kind of practice medicine alongside his father and also recover from the disappointment of having failed. Jyoti Asundi (19:36) Yes. Aarati Asundi (19:37) In 1857, he went back to Cuba and tried again, and this time he passed the exam. Jyoti Asundi (19:42) Which is very commendable because if you think about it, he's got a very easy path forward where people are very accepting of him Philadelphia. He knows he's got a good space for himself over there. He can make a good life. He can make a good living. And he has already earned people's respect enough for them to say, stay here with us. There's a good community for you here. But he's like, "No, Cuba has my heart. That's my dream place. I need to go there." Aarati Asundi (20:10) Yes. So I can totally understand. He probably had a wonderful childhood there, and his family's all there, and he sees the opportunity of what a melting pot Cuba is and tropical, wonderful paradise to be. Yeah, I want to live there. Jyoti Asundi (20:26) You are making me want to live there as well. Aarati Asundi (20:28) Right? Jyoti Asundi (20:28) It sounds like a tropical paradise. Absolutely. Aarati Asundi (20:31) So he passed the exam. However, he spent a little bit more time traveling before he really settled down. He went back to France to take some specialized medical courses in ophthalmology. And then finally, in 1864, he settled down in Cuba with his own practice. He also got married to a woman named Adele Shine, who was born in Trinidad. We don't know much about her. We know she loved music and liked to sing and write short stories and poetry. And she would teach music classes to earn a little bit more money for the family. And she and Carlos had three sons, Charles, George, and Frank. And otherwise, I couldn't really find about their marriage or family life. It sounded great. It sounded like yeah things are going well. Jyoti Asundi (21:17) Very calm and common. Regular folk. Aarati Asundi (21:20) Yes. Carlos himself earned a reputation of being a very kind doctor who treated patients regardless if they could pay him or not. And since he was so well traveled, he spoke fluent Spanish, English, French, and German, and knew all about their cultures. So he was very well set up to treat people who were coming into Cuba from all over the world. Jyoti Asundi (21:43) Yeah, I have very high respect for people who are multilingual. Aarati Asundi (21:48) Me too. Jyoti Asundi (21:49) When you grew up in India, it is very common. So I did not have a choice. I had to learn four languages as I grew up. There was no other choice. I had to do it. Three of them, I was graded on English, Hindi and Marathi. And then, of course, I had to speak my mother tongue that is Kannada. And so there were four languages. But then, you know, just to get along in the neighborhood, you kind of have to pick up the language that your friend's grandma knows, because she's the only one who can give you water you're in the middle of playing. Otherwise if you go to your house and ask for water, then your mom will say it's time to come back home. Do you see the time? Come back in. Oh no, I don't want to do that. So you have to go to your friend's grandma who's in that other side and you have to ask her, I please have some water? And she speaks only Tamil. Aarati Asundi (22:38) And she speaks some fifth language. Yeah. Jyoti Asundi (21:40) Yeah, she speaks only Tamil. So you pick up smatterings of other languages here and there. And I find that it was so natural to me. I didn't even think about. Aarati Asundi (22:50) Growing up in Mumbai is also a big melting pot, kind of like a big city where... Jyoti Asundi (21:52) Absolutely. Yeah it was a huge melting pot. And I-- it was so natural to me. I didn't even think twice about it. And in fact, I actually railed against the fact that I had to spend so much time away from science and math, trying to drill these languages into my brain. But now I find them to be a huge, positive part of my life. We all have a dominant language, open your mind by opening yourself up to other cultures and other languages actually. It just opens up other worlds because you start to learn the literature in that language. Aarati Asundi (23:27) Yeah, their culture and their history, just naturally, their food, know, like everything. Jyoti Asundi (23:29) Absolutely. Yeah. Yeah. It's like living in multiple alternate universes. say, they live like that. Oh that's what they do. And that's their culture. And that's so interesting. And that's their history. And this is why they do this. Because of that, now this is their tradition. All those things make a lot of sense socially. Aarati Asundi (23:48) Yeah, and I think for Carlos, it was like a huge gift. He earned this reputation of being like this international doctor because if a French person came sailing from France all the way to Cuba to trade or something and they had gotten sick on the ship, he was like, "Oh hey, you're from France. I speak French. I was there for three years. I did some college training there." And he could start speaking to them in French and understand their culture. Jyoti Asundi (24:13) And so the person feels, yeah, this person really understands what I'm talking about. Aarati Asundi (24:18) Yeah. So he earned this reputation of like, you know, that international doctor. He's like great for anyone coming into Cuba from anywhere. You know, you speak English, French, German. He's your doctor to go to. And of course, these people who are coming in from all over the world, to this very tropical Cuba. And they're getting tropical diseases like malaria, yellow fever, and cholera. And so naturally, he's like face to face with these diseases all the time. And he's starting to wonder, again, what is the cause of this? Where are these diseases coming from? So in 1868, a cholera epidemic struck Havana. And like we were saying, cholera is not a fun disease. have uncontrollable diarrhea, vomiting, and that rapidly dehydrates them, and that can lead to death. Jyoti Asundi (25:10) Yes. Aarati Asundi (25:12) So as Carlos is treating these patients, he notices something strange. In one particular suburb of Havana called Cerro, there was a street where many patients were coming down with cholera. This was already a bit surprising because it was an affluent part of town and cholera was considered a poor person's disease. But even more surprising was that only one side of the street seemed to be affected. So Carlos heads over to the neighborhood, and he notices that on the side of the street where the people are getting sick, there is an open water canal running right by all those houses. And so he realizes that that must be how the cholera is spreading. And so he writes a letter to the local newspaper recommending that they warn people not to use water from the canal. Unfortunately, though, the newspaper does not publish this warning. He's pretty much ignored. But the more he treats cholera patients, the more he's convinced that it's a waterborne disease. And so he starts making sure his own family is protected by boiling the water that they use. And of course, now we know he's absolutely right. Cholera is caused by ingesting food or water that is contaminated with a bacteria called Vibrio cholerae. And so today, we take measures kill that bacteria by sanitizing our drinking water. Jyoti Asundi (26:35) Absolutely. Yeah, I mean, you've been to Mumbai with me often enough to know that we boil all the water which we drink. We don't just drink water, even if it's coming through a filtration system. Aarati Asundi (26:47) And then we also know if we're traveling around to drink only bottled water, don't drink random tap water at restaurants and things like that. Jyoti Asundi (26:54) Correct. All those yummy street foods that people talk about, we don't indulge because we do not know the source of the water being used on very yummy snacks that we can buy off of the street. Aarati Asundi (27:08) Gotta be careful. So even though his observation about cholera was largely ignored, Carlos was sure he was right. And so he next focused on another tropical disease that he was seeing a lot, which was yellow fever. So like we were saying at the beginning, name yellow fever comes from the fact that patients often develop jaundice, which makes their skin yellow. Jyoti Asundi (27:31) Yes. Aarati Asundi (27:32) The disease was also called Yellow Jack because once there was an outbreak, people would fly a yellow flag or jack on the ship or house as a quarantine sign. And fun fact, by the way, there's a movie that was made in 1938 by MGM, which is a dramatized version of the story that I'm about to tell you called Yellow Jack. It's dramatic, but it's fun. We have people falling in love and all the life on the line. Yeah, everything you need. Jyoti Asundi (28:02) Yes, everything, all the components of a nice little masala movie. Aarati Asundi (28:07) Yes, exactly. Jyoti Asundi (28:08) We call it a masala movie. All the spices to make it a box office success. A bit of romance, a bit of action, a bit of thrill, a bit horror or whatever. Yeah, and a little bit of everything and that will make it a box office success. Aarati Asundi (28:21) Yeah, so it's a fun watch, Yellow Jack, if you're interested in watching a movie about this story, about Carlos Finlay and yellow fever. Fun watch. So yellow fever was a common disease in Cuba. Most of the natives were exposed to it during childhood, but 95% of them recovered. And after that, they were immune. However, starting in the mid 1700s, Cuba, like we said began to become this major international port. And so people from all over the world are sailing into Cuba and were exposed to yellow fever for the first time as adults. Jyoti Asundi (28:57) Yes. Aarati Asundi (28:57) And oftentimes, the disease was a lot more severe in adults. The disease causes fever, headaches, nausea, and muscle pain. It attacks the liver and kidneys causing jaundice and abdominal pain, and ultimately could kill up to half the people who were infected. So Carlos had been treating patients with yellow fever pretty much since he had gotten back to Cuba, but the medical community at large had no idea what caused yellow fever. Carlos himself initially thought that it was something to do with atmospheric alkalinity, so he proposed that basically it was noxious vapors from nearby swamps Jyoti Asundi (29:38) Back to the miasma theory. Aarati Asundi (29:39) Yeah, exactly. And he even wrote two papers putting forward this idea. But then in 1878, there was a severe outbreak of yellow fever in the United States, which killed thousands of people. So big cities like Memphis and New Orleans were hit very hard. And in response, the US government created a special six-person commission which included a bacteriologist, epidemiologist, pathologist, medical student, civil engineer, and a support member to go to Cuba stay there for a year and work with their Cuban counterparts to try and figure out what was the cause of the disease. And Carlos, who by now has become a member of the Royal Academy of Medical, Physical, and Natural Sciences in Havana, was one of those people chosen by the Cuban government to work with the Americans. Jyoti Asundi (30:32) He is of international stature, he knows all languages, he can communicate effectively in spite of his stutter, and he has a very deep knowledge and skill base, yes. Aarati Asundi (30:41) Yes, natural choice. After a year, they still hadn't figured out the cause. But by working with the Americans, Carlos did a 180 on his original hypothesis. And he realized that it couldn't possibly be atmospheric conditions that were causing the disease. And so he went back to germ theory, that it must be some sort of infectious agent. In 1879, he received the report Americans' one-year stay in Cuba. And through reading this and through all of his knowledge, he put together three basic facts. First, that yellow fever must be a germ disease. Second, it's not caused by contact with other patients, their secretions, or contaminated air, food, or water. And third, it was common to see lesions in the capillary walls of patients, suggesting that the disease came in through the blood vessels somehow. Jyoti Asundi (31:38) Ah! Aarati Asundi (31:39) So how is possible? That's a weird one. So one account that I was reading, could be completely fabricated. It could be, it's a myth or a tall tale, Jyoti Asundi (31:49) For the movie probably. Aarati Asundi (31:51) No, it wasn't for the movie. It's not in the movie. But I think it's just like science storytelling, gone rogue a little bit. Jyoti Asundi (31:57) Taking a few liberties, let us say. Aarati Asundi (31:59) Yes. It could be true. But the story goes that Carlos was saying his prayers before bed one night, and a mosquito kept buzzing around him. And that gave him the idea that it could be a mosquito that is causing yellow fever. Jyoti Asundi (32:17) Actually, you know what? I do believe this can be true. Aarati Asundi (32:20) It might be. Jyoti Asundi (32:21) I don't think is scientific storytelling liberty, because if you hark back to our periodic table and how he got it in a dream, then that point I had brought up the other one about the organic carbon ring... Aarati Asundi (32:36) Yeah, Kekule. Yep. Jyoti Asundi (32:36) ...by Kekele. And the third one I want to point out is Archimedes who says "Eureka!" in the bathtub. So in all three cases at that moment of discovery of all the dots connecting you are in a very relaxed state. Either you are in a dream state or you are in a bath finally releasing the exhaustions of the day. Or in case of Carlos, he is in prayer, letting things go, surrendering, calming his mind. Finally, all the pieces that are already present in your brain click together to give you the answer. So I believe this story. Aarati Asundi (33:14) Yes. It could be I think it's just more of like, you know, Mendeleev and the periodic table, we have his account where he actually wrote down, "I saw this in a dream." With Carlos, we don't have his account of how he came up... Jyoti Asundi (33:29) His written accounting. OK. Aarati Asundi (33:30) Yeah, how he came up with the idea of a mosquito, but yeah. Jyoti Asundi (33:32) But I believe it. OK, I believe it. It makes very good sense to me. Aarati Asundi (33:37) But he did say, "I was thus led to conclude that the transmission was affected through the agency of some blood sucking insect, which was peculiar to yellow fever countries. In searching for such an insect, I came across the day mosquito of Havana." And what was remarkable about that is that he even identified the specific species of mosquito whose Latin name is Aedes aegypti as the transmitter. Jyoti Asundi (34:10) Nice. Okay. Aarati Asundi (34:11) I was trying to look up like how many mosquitoes species are there. And in the world, it's like thousands. There's thousands of mosquito species. In Cuba itself, I'm not 100% sure. But I think this was still a very big accomplishment that he was able to identify the actual species out of all the mosquito species. Jyoti Asundi (34:31) Absolutely. Aarati Asundi (34:31) This is the one that transmits yellow fever. Jyoti Asundi (34:34) Yeah. Malaria also is transmitted via mosquitoes, but it is through the Anopheles, I think. Is it the... Aarati Asundi (34:25) Oh we'll get there. Jyoti Asundi (34:41) Oh okay. Aarati Asundi (34:42) But the problem is Carlos didn't have concrete proof. And he knew that this was a controversial idea because, again, this is the first time that anyone's actually suggesting that this insect causes this disease. And he knew how controversial it was going to be. And so for a while, he kept quiet. And even when there were conferences that were literally held about yellow fever and how it spreads, he would attend and he would hint very strongly, but he never came out and actually said, I think it's a mosquito. But he would hint, like, it must be transmitted through the blood, possibly through some sort of small vector. He would dance around the topic. Yeah. Jyoti Asundi (35:28) Yes, I can see why because even now you're saying that they were arguing whether it was a miasma versus the germ theory. Now you're introducing yet another component to the whole thing. It's like I haven't even proven what is the microorganism involved? And now I want to jump over and say that microorganism in addition requires the vector of the mosquito. I can see the challenge in trying to convince people. Aarati Asundi (35:58) It's a tough one. Yeah. And so he's not coming out and saying this, but meanwhile, he's gathering the equipment and authorization to run a preliminary experiment. _______________________________________________________________________________________ Aarati Asundi (36:17) Hi everyone, Aarati here. I hope you're enjoying the podcast. If so, and you wish someone would tell your science story, I founded a science communications company called Sykom, that's S-Y-K-O-M, that can help. Sykom blends creativity with scientific accuracy to create all types of science, communications, content, including explainer videos, slide presentations, science, writing, and more. We work with academic researchers, tech companies, nonprofits, or really any scientists. To help simplify your science, check us out at sykommer.com. That's S-Y-K-O-M-M-E-R.com. Back to the story. _______________________________________________________________________________________ Aarati Asundi (37:04) In the fall of 1881, he took 20 healthy people and he made them stay under the same living conditions. So they got the same food, same water, et cetera. And then he exposed five of them to some mosquitoes that had recently bitten yellow fever patients. very shortly after, four out of the five people developed yellow fever symptoms. Meanwhile, the 15 people that had not been exposed to the mosquitoes at all stayed healthy. Jyoti Asundi (37:31) Yes. Aarati Asundi (37:32) So armed with these results, he goes to the Royal Academy on August 14th, 1881, and he presents what is now his most famous work, "The Mosquito Hypothetically Considered as the Agent of Transmission of Yellow Fever." This work, when he presented it, was met with absolute silence. Everyone ignored it. In an article by Jonathan Leonard for the Bulletin of the Pan-American Health Organization, he writes, "as if the largest tree in the forest had fallen, but no one heard the crash". Jyoti Asundi (38:06) Wow that's very apt. Aarati Asundi (38:09) But even Carlos understood why. It wasn't, like I said, a novel idea that insects could be disease vectors, but it hadn't been proved before. And people had already accepted the idea that diseases were caused by contaminated food or water or could spread from person to person. So Carlos's small experiment of 20 people wasn't convincing enough. Carlos said, "these experiments are certainly favorable to my theory, but I do not wish to exaggerate their value considering them final. I understand but too well that nothing less than absolute incontrovertible demonstration will be required before the generality of my colleagues accept the theory so entirely at variance with ideas which until now have prevailed about yellow fever. My only desire is that my observations be recorded and that the correctness of my ideas be tested through direct experiments." Jyoti Asundi (39:10) Wow. Spoken like a true scientist. Aarati Asundi (39:13) Very much so. Jyoti Asundi (39:14) Very is pragmatic, very calm. He thinks he's right but he knows he doesn't have sufficient proof. Aarati Asundi (39:21) He's got n of 1. Jyoti Asundi (39:22) Yeah and he's like let time be the test of this truth. Aarati Asundi (39:28) Mm-hmm. So he's like, yeah, I understand. I have a very small sample size. I've done the experiment one time. It worked in the way that proved my hypothesis. But now we have to do it with bigger populations, more people under different conditions, and show that it's really, really true. I It was a tough one to prove though, because although he tried to repeat his experiments, he didn't have some key facts. So he didn't know that there were certain time windows that were associated with the transmission. Yellow fever is caused by a virus. And so that means that there needs to be enough time for the virus to replicate inside the patient's body first, and then in the mosquito's body. Jyoti Asundi (40:11) That's correct. Aarati Asundi (40:13) So the first patient with yellow fever has to be bitten within the first three to five days of being sick. Then the virus would enter the mosquito's gut, replicate, and travel to its salivary glands. And that took about eight to 12 days. And only after that could it pass on the virus. And so Carlos didn't know this. And he was also very reluctant to test his theory very rigorously because he knew that that meant giving people yellow fever and putting their life at risk. Jyoti Asundi (40:47) Absolutely. This is the problem. This is like you're trying to conduct a clinical trial, but you're trying to make healthy people sick in order to prove it. Aarati Asundi (40:55) And it wasn't easy to give animals yellow fever either. So he couldn't just do this experiment on mice or rats or something that is what we would automatically do today. Today, we can actually take a needle and inject a mouse with the virus and give the rat yellow fever. But to make a mosquito bite a rat and for the rat to develop yellow fever, it just didn't happen very easily. So because he had to work on humans, he kept trying to do the experiment in ways that he thought would only result in a mild fever, like exposing healthy volunteers to mosquitoes that had very recently bitten yellow fever patients, thinking that the longer it sat in the mosquito's body, the more potent it would get. And so if the mosquito bit the new patient earlier, the patient would develop a mild fever. But of course, it didn't work because it was too soon. It needed eight to 12 days to replicate. Jyoti Asundi (41:50) Yes, got it. Aarati Asundi (41:51) So he wasn't able to get very consistent strong results because he didn't know these key facts. Jyoti Asundi (41:58) He didn't have key pieces of data. Aarati Asundi (42:01) Yes. So he works at this for the next 20 years from 1881 to 1901. Jyoti Asundi (42:09) Very patient person. Aarati Asundi (42:10) So patient. This is why I gave up lab research and working in a lab because I'm not a patient person. I don't have this kind of patience. Jyoti Asundi (42:19) Yes. Aarati Asundi (42:20) It's very, very difficult. Jyoti Asundi (42:23) Yes. Aarati Asundi (42:24) So Carlos published over 40 papers on his studies in yellow fever, including ways to prevent transmission. For example, one very obvious thing he pointed out was that houses in Cuba should have insect screens on the windows like they did in the US. Another was locating still water pools and swamps where mosquitoes laid their eggs and destroying them. Another idea was keeping yellow fever patients on high levels of hospitals where mosquitoes were not as likely to be able to fly and get access to them. Jyoti Asundi (42:57) Very good ideas. Aarati Asundi (42:58) Yeah, but again, all largely ignored. Jyoti Asundi (43:02) Humanity suffers in the meanwhile. ⁓ Aarati Asundi (43:04) Yeah. That is until around 1898 when politics and war actually helped science for once in.... Jyoti Asundi (43:13) No way! Aarati Asundi (43:15) I know! Jyoti Asundi (43:15) What is this? How did that ever happen? Aarati Asundi (43:18) Yeah, so Cubans during this time had gotten very tired of Spanish colonial rule and they started to rebel. The US was highly sympathetic to the rebels and took sides with them against the Spanish. So on February 15th, 1898, US Navy battleship called the Maine that was docked at Havana Harbor blew up with Spain taking credit for the attack. Jyoti Asundi (43:44) I see. Aarati Asundi (43:44) It didn't immediately spark a war, but it did result in the very catchy rallying cry, "Remember the Maine, to hell with Spain. Jyoti Asundi (43:52) This is the TikTok culture of the past, where you know, you have very short attention span, you catch it with these catchy phrases. And that's what you see even politicians doing today. Give them a little, little rallying cry, like, "Make America great again", for example, is this itty bitty rallying cry. That's all the attention span you have. And then immediately your mind programmed to follow that person. Aarati Asundi (44:18) Yeah, so these marketing people, you know, working hard. Jyoti Asundi (44:23) Incredible. Aarati Asundi (44:24) Anyway, shortly after this, the Spanish-American war started and Carlos is in the midst of all of this helping care for the US troops who were entering Cuba and falling sick with yellow fever, malaria, and typhoid fever. So once again, these infectious tropical disease have become the US's problem. All their are falling sick. So they put together a Typhoid Fever Board, which was led by military surgeon Dr. Walter Reed, who systematically cleaned up and sanitized all the military encampments. Jyoti Asundi (45:00) Okay. That name seems familiar to me, yeah. Aarati Asundi (45:03) Right? Yes, it was to me too. And this is why I was like, I feel like I've heard of Walter Reed and I haven't heard of Carlos Finlay. Interesting. But you know Walter Reed was American and you know how our history books get written. We don't hear about Carlos because he was Cuban. Jyoti Asundi (45:18) Yes, absolutely. I was going to say that, but that is really, that's exactly how life works. Yeah. Aarati Asundi (45:25) Yeah, But we'll get there. We're going to talk about this more. So Walter Reed systematically cleans up and sanitizes all the military encampments. And this effectively got rid of typhoid fever. However, yellow fever didn't seem to be affected. So again, we're back to the US team trying to figure out the cause of yellow fever. And they're chasing down every theory that they can think of. Any scientist who said, I think it could be this bacteria, or I think it could be this plant, they would go after it. And ultimately, they would disprove it. In doing this, they had heard about Carlos Finlay and his mosquito idea. But only one member on the board, Jesse Lazear, thought it had any merit. Jyoti Asundi (46:10) Okay. Aarati Asundi (46:11) But soon they got to the point where they were practically out of options. And so they decided, what the heck, let's pay Carlos a visit. Carlos welcomed them and gave them everything they needed to set up their own experiments. They started exposing volunteer soldiers and members of the Typhoid Fever Board to infected mosquitoes. Ultimately, three people developed yellow fever, Jesse Lazear and James Carroll, who were surgeons on the Typhoid Fever Board and a volunteer soldier named William Dean. James Carroll and William Dean developed mild cases and recovered, but sadly, Jesse Lazear died. Jyoti Asundi (46:49) Isn't that sad? Aarati Asundi (46:50) Yes. Jyoti Asundi (46:50) You said he was the only one who was in favor of Carlos' theory to begin with and he's the one who takes the hardest hit on this one. That is ironic in a very sad way. Aarati Asundi (47:02) Yes. Walter Reed had been in Washington at the time that these experiments were conducted, but when he heard the news that the experiment may have actually worked, he rushed back to Havana. These results were not at all conclusive, but there was finally enough evidence to give Walter Reed and the rest of the board hope that maybe they had found the cause. From November to December of 1900, Walter Reed and his team carried out very carefully thought out experiments to rule out all other causes of yellow fever and to prove this mosquito theory. Some of these experiments, I was just like cringing and shuddering. And again, beautifully portrayed in that 1938 movie. Jyoti Asundi (47:45) Okay, okay. Aarati Asundi (47:46) So they made volunteers sleep for 20 days in dirty beds made with clothes and sheets that were soaked in the bodily fluids of patients that had yellow fever. Jyoti Asundi (47:59) But luckily that does not give them the fever so that does not transmit. Aarati Asundi (48:03) Yeah, so none of them got yellow fever. They had some volunteer sleep in a room filled with yellow fever infected mosquitoes, but with nets around the bed to protect them from getting bitten. And none of them got yellow fever. Then one person from this group was exposed to the infected mosquitoes for three days and he developed yellow fever. Jyoti Asundi (48:26) Okay. Aarati Asundi (48:26) This finally convinced them and they immediately started taking steps to properly quarantine patients with yellow fever away from mosquitoes, get people who are still susceptible to yellow fever out of Havana and go after the mosquito population by killing all their eggs so they couldn't reproduce. Jyoti Asundi (48:44) Okay, yes. Aarati Asundi (48:45) So basically everything that Carlos had said to do 20 years ago. Jyoti Asundi (48:49) Now they are finally getting on the program. Aarati Asundi (48:52) Mm-hmm. The result was very obvious. In 1900, there were at least 300 deaths in Havana from yellow fever. One year later, after these measures were in place, that number dropped to 18 deaths. Jyoti Asundi (49:08) Dramatic. Aarati Asundi (49:09) Huge. Jyoti Asundi (49:09) Dramatically positive results. Aarati Asundi (49:13) So like we were saying before, Walter Reed ended up getting a lot of the credit for this work, to the point that Carlos was pretty much overshadowed. Jyoti Asundi (49:23) Yery, very sad. Aarati Asundi (49:26) Walter kept on telling people this was all Carlos Finlay's theory. He's the one who came up with the idea. Jyoti Asundi (49:31) Oh, oh wow. Aarati Asundi (49:33) Yeah. But it was really the media and the storytelling who ignored Carlos. And it became Walter Reed, the savior of the US Army, who figured out how yellow fever was spread through mosquitoes. And Carlos Finlay was at the most a footnote. But it sounded like Walter Reed really did his best to be like, "It was not us. It was all Carlos and his ideas and his theories. Everything was him." So which makes it even more disappointing. Jyoti Asundi (49:57) Wow. It gives it... yeah. Yes, because it's the storytellers who purposely got it wrong in order to maximize the dramatic effects of it. Aarati Asundi (50:11) Yeah Jyoti Asundi (50:11) It's like, "But our audience is in the US. Our paycheck comes from the US or the US, the people who read it in the US. And Carlos is not this heroic figure or sympathetic figure or any sort of figure. He's not even a blip on the radar in the US psyche." Aarati Asundi (50:30) Yeah, they can say Walter Reed is from our side. He's an American. And he saved our troops. Jyoti Asundi (50:35) We did it, we did it, uh-huh. Aarati Asundi (50:36) Yeah, we did it. Yeah, yeah. Reed's success is what finally proved Carlos's theory and Carlos did receive of it. Jyoti Asundi (50:45) Okay, but maybe more in Havana and Cuba. Aarati Asundi (50:48) Exactly. So in 1902, after the war was over and the US pulled out of Cuba, Carlos was made Chief Health Officer of Cuba and president of the Board of Health. worked on eradicating multiple infectious diseases, including smallpox, neonatal tetanus, and creating sanitization codes. And his work paved the way for other scientists like Ronald Ross in 1897 to show that malaria was transmitted through another species of mosquito, the Anopheles mosquito. Jyoti Asundi (51:21) Yes, yes. So we are going so far away. We were like, "Is it the miasma or is it the germ theory?" And from there now we have moved over the no miasma, going to the germ theory. But then in addition, we need a vector. And then who is the specific vector? Like you said, a very specific type. It's not just, "Oh a mosquito". No, no, this type of mosquito for the yellow fever this type of for the malaria. And I think that the tsetse fly, think is also the carrier, specific carrier for sleeping sickness. And we can't just take these, you know, little vermin in basically to be innocuous creatures also inhabiting our species. No, they get into dirty places. They get into infected areas and bring that infection back. So be careful. That's so vital to human health. Aarati Asundi (52:18) Yeah. And he's the one who laid that foundation so Ronald Ross wasn't laughed out of the room when he proposed that a mosquito could be causing malaria. Jyoti Asundi (52:26) Yes, yes. Aarati Asundi (52:28) Walter Reed also said that Finlay's work is what made the Panama Canal finally possible because thousands of workers had been dying due to malaria and fever. In 1884, the death rate reached as high as 200 workers a month. Jyoti Asundi (52:47) A month! If 200 people were dying per month, how many more were just laying there sick and not working? Aarati Asundi (52:53) Yeah, and the US is also like why are we sending healthy young men over to die? You know? Jyoti Asundi (52:59) Absolutely. Aarati Asundi (52:59) Like just to languish and die. Yeah. So huge. Carlos was also nominated for the Nobel Prize seven times, although he actually never ended up winning it Jyoti Asundi (53:11) Very sad. Aarati Asundi (53:13) He totally deserved it. In 1908, Carlos retired at the age of 75, and seven years later, he died from a stroke on August 20th, 1915. He has received many posthumous honors. The Finlay Medical History Museum in Havana was founded in 1962. In 1981, Carlos Finlay was also commemorated on a stamp. And he has a statue on the bayfront in Panama City right next to the canal that he made possible. Jyoti Asundi (53:44) Beautiful. At least he got some recognition. And he lived a very good life in the place that he loved. So you have to think about it as a successful life. Aarati Asundi (53:54) But as is the theme with all of these scientists, I feel like all of them are just like, as long as we helped somebody in our time here, we're happy enough with that. Jyoti Asundi (54:00) Yes, yes. I think if you look at it from Carlos's point of view, he would be happy enough that he was able to prove it one way or the other. And even not even as a self gratification thing, more like, okay, that helps humanity. Let's move it forward now. This was a great story. And for a person who grew up in tropical with mosquitoes buzzing all over the place, this really brought back a lot of memories. Very annoying buzzing. Like you said, if you hear the buzz, you do have this little slither of fear in you. It's like, Oh goodness, I don't know what that buzzer is carrying around. Where has it been? Which swamp, which dirty creek did it land on before it's going to come and suck my blood? Aarati Asundi (54:51) You don't want to be under a blanket either because it's so hot there. Jyoti Asundi (54:55) Yes, yes. Aarati Asundi (54:55) So I remember getting one of your very thin saris, covering with that and trying to create this mosquito net around me while I was sleeping. Jyoti Asundi (55:05) Yes, exactly. Creating a faux mosquito net wherever we go because we are not always in the comfort of our home when we travel in India. So you are stuck with the mosquito of that area and who knows what it carried. Thank you for a beautiful story. Aarati Asundi (55:24) Yes, hopefully it gave your brain a little bit of a break. Yes. Jyoti Asundi (55:28) Yes. And nostalgia for a beautiful warm tropical area. Aarati Asundi (55:35) Thanks for listening. If you have a suggestion for a story we should cover or thoughts you want to share about an episode, reach out to us at smartteapodcast.com. You can follow us on Instagram, TikTok, and BlueSky @smartteapodcast and listen to us on Spotify, Apple Podcasts, YouTube, or wherever you get your podcasts. And leave us a rating or comment. It helps us grow! New episodes are released every other Wednesday. See you next time!