Paul-Louis Simond, world traveler working on multiple diseases

Paul-Louis Simond in his laboratory in Constantinople 1911-1913 © Institut Pasteur/Musée Pasteur

A French naval medical officer, Paul-Louis Simond traveled the world and studied many diseases. After heading up a leprosarium in French Guiana from the age of 24, he spent several years in Indochina where he battled smallpox, and then in China.

Plague, yellow fever and cholera

Joining the Institut Pasteur at 37, he worked alongside the first group of Institut Pasteur scientists. Two years later, he was sent to the frontline of the plague in India, where he made his major discovery: the role of fleas in disease transmission. He then headed up the Institut Pasteur in Saigon, Vietnam. Two years later, he took part in a lengthy assignment to Brazil to study yellow fever and come up with preventive measures. On his return to France, he taught at the École d’application du service de santé des troupes coloniales in Marseille, and then went to Martinique on another yellow fever assignment. He then tackled cholera in Constantinople where he was seconded to direct the Imperial Institute of Bacteriology, before being appointed to head up medical services for troops in Indochina. This would be his last overseas assignment: in conflict with the military authorities, he left the colonial troops at the age of 56 and withdrew to his native Drôme region, where he devoted his time to public health work in the region.

A renowned botanist

While Paul-Louis Simond is known for his many scientific accomplishments, he was also an enthusiastic botanist. The Museum of Paris, to which this botany enthusiast donated 226 watercolors of orchids from Indochina accompanied by his own handwritten descriptions, named a dozen orchids after him. This flower also features on his ex-libris alongside a salamander (for his early research at the Institut Pasteur), a rat, a flea and a yellow fever mosquito.

Discovery in Karachi: the flea, vector of the plague

In 1897, at the request of the Institut Pasteur, Paul-Louis Simond took over from Alexandre Yersin, conducting a serotherapy campaign against the bubonic plague around Bombay, India, which was suffering a severe outbreak. He traveled extensively throughout the country and patients flocked to see him, he wore himself out… and he recorded his observations. Having noticed that some patients had small blisters suggestive of insect bites, he came to believe that rats were not transmitting the disease directly to humans. In Karachi, where he was later sent during a plague outbreak, he decisively proved that fleas transmitted the plague, from rat to rat and by deduction from rat to humans. He wrote: “That day, June 2, 1898, I felt an inexpressible emotion at the thought that I had just uncovered a secret that had troubled humanity since the plague first appeared in the world.” Associating rat extermination with insect control, his discovery considerably reduced the incidence of the disease in many countries.

Timeline of the life of Paul-Louis Simond

> July 30, 1858
Born in Beaufort-sur-Gervanne (Drôme).

> 1882-1886
Director of the Acarouany leprosarium in French Guiana.

> 1886-1887
M.D. on leprosy in Bordeaux.

> 1890-1894
Naval Medical Officer, 2nd class. Transferred to the Far East, takes part in smallpox vaccination campaigns, conducting oceanographic research in the Gulf of Tonkin. Writes Notes d’histoire naturelle et médicales in Longzhou, China.

> 1895-1897
Takes the microbiology course at the Institut Pasteur and then conducts research into coccidia.

> 1897-1898
Sent to the British Indies to fight plague by the Institut Pasteur. The Annales de l’Institut Pasteur publish his work on the transmission of the disease.

> 1898-1901
Director of the Institut Pasteur of Saigon. Chevalier of the Legion of Honor.

> 1901-1905
Works on yellow fever in Brazil for the Institut Pasteur.

> 1906-1910
Teaches at the École d’application du service de santé des troupes coloniales (Marseille).

> 1908-1909
Works on yellow fever in Martinique.

> 1911-1913
Director of the Constantinople Imperial Institute of Bacteriology.

> 1914-1917
Director of medical services for troops in Indochina. Leaves the colonial troops.

> 1919-1947
Deputy mayor of Valence, helps set up a day nursery and a tuberculosis dispensary in the town.

> March 18, 1947
Dies in Valence (Drôme).