- A dictionary of medical eponyms

Alexandre-Émile-John Yersin

Born 1863
Died 1943

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Swiss-French bacteriologist, born September 23, 1863, Morges; died March 1, 1943, Nha Trang, Annam, Indochina [now in Vietnam]. His name has also been given as Alexandre-John-Émile Yersin.

Biography of Alexandre-Émile-John Yersin

Alexandre-Émile-John Yersin was one of the discoverers of the plague bacillus, now named Yersinia pestis. In 1884, with Émile Roux, he demonstrated the existence of diphteria exotoxin.

Yersin's father, also named Alexandre Yersin (1825-1863), was a teacher of natural sciences in Aubonne and Morges. He died two weeks before the birth of his son Alexandre-Émile-John.

As a child Alexandre Yersin had a keen interest in nature, collecting insect that he studied carefully. He grew up Morges, where he knew Victor Morax (1866-1935). He received his secondary education in Lausanne before he entered the university there. He subsequently attended the University of Marburg and the Paris Faculty of Medicine, where he worked in professor André Victor Cornil's (1837-1908) laboratory at the Hôtel-Dieu.

An accident brought him in contact with Pierre-Paul-Émile Roux (1853-1933). Yersin had cut himself while performing an autopsy on a patient who had died of rabies, and was saved by an injection of a new therapeutic serum given to him by Roux. In 1888 Roux hired him as his assistant in his research work on rabies. From Paris, Yersin moved on to Berlin to continue his bacteriological studies under Heinrich Hermann Robert Koch (1843-1910), conducting studies on the tubercle bacillus. In 1889 he was engaged by Roux to prepare and teach a course in microbiology at the Pasteur Institute in Paris, and began his own research, with Roux, on the toxic properties of the diphteria bacillus.

Upon his return to Paris, Yersin began his own research with Roux, at the Institut Pasteur, In 1889, however, he suddenly embarked as a ship’s doctor on a steamer bound for Saigon and Manila. He returned to Paris and left again for Indochina; and during three dangerous expeditions into the interior, he discovered the high plateau of Langbiang, where he founded a small colonial village. The area soon became a vacation centre for Europeans, and the city of Dalat was developed there. In 1935 the municipal authorities established the Lycée Yersin at Dalat.

A sailor in Hong Kong
In 1890 Yersin suddenly left Europe to serve as a physician for the Messageries maritimes aboard a steamer bound for Saigon and Manila, and soon began his four-year exploration of the central region of Indochina. He discovered the sources of the Dong Nai River and explored the Lang Bian Plateau, where he recommended that a town, the future Da Lat, be built. In 1894 he joined the colonial health service – Corps de santé des colonies – and was sent to Hong Kong to conduct research on bubonic plague epidemic that was sweeping through China.

However, Yersin was not the only bacteriologist to rush to the scene. The Japanese bacteriologist Shibasaburo Kitasato (1852-1931) arrived a few days before Yersin. Kitasato was championed by Dr James A. Lowson, a naval surgeon who was Superintendent of the Government Civil Hospital. Within a few days of his arrival, Kitasato found a bacillus and announced it to the world via telegraph. His discovery was published in The Lancet of August 13 that year.

Yersin arrived in Hong Kong on June 15th, 1894 and seven days later, working in a small bacteriological research laboratory set up for him, he isolated the plague bacillus.

Kitasato published his findings in Japanese and English; Alexandre Yersin published in French. People in different parts of the world credited one or the other with the discovery, depending which journals they had read. Yersin named the organism Pasteurella pestis after his teacher, but since 1970 the bacillus has been known as Yersinia pestis.

Nha Trang – his new home
The next year, 1895, Yersin established a laboratory at Nha Trang. There he prepared serums against plague in human beings and cattle and studied cattle diseases, tetanus, cholera, and smallpox. To finance the laboratory, designated the Pasteur Institute of Nha Trang in 1903, he undertook the cultivation of corn (maize), rice, and coffee and introduced the rubber tree (Hevea brasiliensis) to Indochina.

In 1904 he was recalled to Paris and continued his research at the Institut Pasteur, of which Roux had become director. With Léon Charles Albert Calmette (1863-1933) and Amédée Borrel (1867-1936) he made the important observation that certain animals can be immunized against the plague through the injection of dead plague bacteria.

He then returned to Nha Trang, where a branch of the Institut Pasteur had been established under his direction. There, in modest laboratories, Yersin perfected an antiplague serum that made it possible to reduce the death rate from 90 percent to about 7 percent.

With the assistance of Paul Doumer (1857-1932), then government general of Indochina, a medical school was founded at Hanoi; Yersin directed this centre of study and research for many years. Through Yersin’s work Indochina was able to control the epidemics that beset the country, especially malaria. In recognition of his medical achievements, the French government appointed Yersin honorary director of the Institut Pasteur in 1933.

The landowner
Besides his activity in science and medicine in Indochina, Yersin conducted research in agronomy. He had a ranch in Nha Tranf where he raised horses. He also contributed to the Vietnamese rubber industry, as he is responsible for introducing the Brazilian rubber tree to Vietnam. During the years 1920-1923 Yersin was also responsible for the first quinquina plantations in Vietnam, where quinine (Cinchona ledgeriana) are produced.

His interest in the cultivation of grains and in soil conditions led him to initiate a series of ecological studies. He also reflected on the natural history of Indochina, having become fascinated by the flora and Fauna of his adopted country. Yersin became deeply concerned over the needs of the sick and the poor and fought hard against the exploitation of the lower classes. At Nha Trang he lived a simple life and was beloved by the people in the region for his humility and care he gives to the people. The locals lovingly calls his home Lau Ong Nam (Home of Fifth Uncle) or Thap Nga (Ivory tower).

In 1940, Alexandre Yersin in poor health, returned to France for the last time. In 1941, he returned to his beloved home in Nha Trang where he remained and passed away in January 3, 1943 at Suô'i Giao southwest of Da Lat, at the age of 80. In his will, he requested to be buried in Nha Trang, close to his beloved people. Every year, on March 1st, out of respect and gratitude to his contribution to this region, many of the inhabitants still come to his grave, bringing joss-stick and fruits as offerings.

The Alexandre Yersin French International School Ha Noi is named in his honour. This school is a not-for-profit organization under the guardianship of the Embassy of France in the Socialist Republic of Viet Nam.

We thank Patrick Jucker-Kupper, Switzerland, for information submitted.

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