Biography of Carlos J. Finlay

The Conquest of Yellow Fever. Author: Robert Thom. Source: Collection of the University of Michigan Health System, Gift of Pfizer Inc. UMHS.37

Born on 3 December 1833 in Puerto Príncipe (today's city of Camagüey) in a French-Scottish family, Carlos J. Finlay studied at some of the most prestigious schools and institutes in the world.

After receiving his primary education at home, his parents sent him to France, where he could profit from high quality learning opportunities. His studies persuaded him to follow the professional path of his father, who was a well renowned doctor and physician in Cuba.

However, diseases that indisposed him few times and political troubles affecting Europe at that time obliged him to go back home repeatedly, then to leave France in order to continue his studies in Germany, in United Kingdom, and ultimately in the United States. It is at the Jefferson Medical College of Philadelphia that he finally graduated in medicine, on 10 March 1855.

In Philadelphia, he befriended his professors and mentors John Kearsly Mitchell and his son Silas Weir Mitchell. These two were both high distinguished academicians and partisans of the germ theory of disease. This theory constitutes nowadays one of the founding principles of the modern medicine as well as of clinical microbiology, but at that time it was still at the experimental stage. It postulates that several diseases result from the contamination of the body by external microorganisms.

The Mitchells strongly aimed to see their brilliant disciple embarking on his medical career in the United States, but Finlay desired to go back to his natal island and work beside his father. After eight years of travels and specialization courses abroad, in 1864 he finally began practicing as a doctor in La Havana.

Here, his profession brought him face to face with epidemics periodically ravaging his country: malaria, yellow fever, cholera and others. These plagues were all the more merciless so as the medical science still hadn't any answer about their origins and their ways of propagating. Thus, Finlay resolved to inquiry into these diseases, in order to fill the scientific void on them.

He first developed a new theory on cholera, as his research had persuaded him that this disease is transmitted by water. However, this thesis remained disregarded by the scientific community. Then, he started focusing on yellow fever, which was causing huge human and economic losses in the Americas and especially in Cuba.

On 14 August 1881, Finlay presented at the Royal Academy of Medical, Physical and Natural Sciences of Havana a work titled “The Mosquito Hypothetically Considered as the Transmitting Agent of Yellow Fever”. In this paper, he first asserted the hypothesis that the mosquito Culex fasciatus, currently named Aedes aegypti, is the agent transmitting yellow fever. Yet, this thesis as well was rejected/disdained by academicians. The peers of Finlay considered it fanciful, but actually it was just too revolutionary for the scientists. At that time in fact, the idea of insect vectors of diseases in itself was still ahead of its times.

Since 1881, Finlay carried out several hundreds of experiments on people who voluntarily exposed themselves to the bite of infected mosquitos Aedes aegypti. Unfortunately, very few trials succeeded, because, even if the intuition of Finlay was correct, his methodology for the experiments was not. Thus, the inconstancy of his empirical results was more and more reinforcing the opinions rejecting, and even ridiculing him.

Finally, it is a medical team of the U.S. Army leaded by the doctor Walter Reed that succeeded in proving the validity his theory. The yellow fever was a plague not only for Cubans, but also, and even more, for foreigners. During the Spanish-American war this disease killed more people than the conflict in itself. Hence, the US Army sent the team of Reed to Cuba in order to find a remedy.

At first, Americans doctors as well greeted with scepticism the mosquito theory of Finlay, but soon they resolved to appeal for his aid. Finlay demonstrated to have a great spirit of scientific solidarity in furnishing them his infected samples of Aedes aegypti along with his assistance. This collaboration enabled them to make a great leap forward in scientific research and save millions of lives.

Reed was wrongly considered as the discoverer of the yellow fever way of transmission. Yet, the American doctor has always given this credit to Finlay. When he died, Finlay was highly esteemed amongst the scientific community as well as by the public administration of Cuba. Pioneer of the struggle against yellow fever and precursor of the theory of biological vectors of diseases, he deeply innovated the medical science through several findings on different issues. Furthermore, he held few positions of high responsibility within the public health system of his country.

Throughout his career, he was awarded of several prizes and honours by scientific institutions all around the world. He has been several times nominated for the Nobel Prize, but unfortunately in vain.

Nevertheless, many institutes, streets and places in the world were named after him and, after his death, the Pan American Health Organization declared the 3 December, birth day of Carlos J. Finlay, as the Medicine Day in the Americas.

Back to top