Émile Alexandre Alexandre Yersin, often known as John Yersin, was a Franco-Swiss bacteriologist. He is well known for identifying the bacillus that causes bubonic plague, ‘Pasteurellapestis,’ which is today known as ‘Yersinia pestis.’ He contributed to the eradication of an epidemic sickness like the plague, which took the lives of millions of people over the course of a century. He spent most of his life investigating the bubonic plague in France and French Indochina, a nature lover and good student since infancy. He developed the first anti-plague serum with the help of fellow bacteriologists Émile Roux, Albert Calmette, and Amédée Borrel. Later, based on his studies in this arena, more research was directed toward antiserum treatment, antibiotic use, and infection prevention through the development of better vaccinations. These actions eventually resulted in the abolition of the disease. The method he used to make the discovery is still applicable today, and scientists employ it frequently when confronted with a new contagious disease. A similar strategy has lately been used to research the treatment and cure of diseases such as AIDS, SARS, Chikungunya, and, most recently, the Ebola virus.
Childhood and Adolescence
Yersin was born in Aubonne, Canton of Vaud, Switzerland, on September 22, 1863. His ancestors were originally from France. His father, Alexandre Yersin, was a natural sciences teacher in Aubonne and Morges. Unfortunately, he died just two weeks before his kid was born.
Yersin was fascinated by nature as a child and collected a variety of little organisms such as insects to study. He was born in Morges and attended high school in Lausanne before attending university there.
In the late 1980s, he attended the University of Marburg and the Paris Faculty of Medicine. At the Hôtel-Dieu, he worked in Professor André Victor Cornil’s laboratory.
Alexandre Yersin’s Career
By chance, he met fellow bacteriologist Pierre-Paul-Émile Roux. He injured himself accidentally while performing an autopsy on a dead rabies case. Roux, by infusing a new medicinal serum, saved his life.
Roux invited him to join the École Normale Supérieure’s Louis Pasteur research laboratory in 1886. He joined Roux in the development of the anti-rabies serum not long after.
He got his Ph.D. in 1888 after presenting a thesis titled ‘Étudesur la Développement du Tubercule Experimental,’ after which he spent a few months in Berlin with Heinrich Hermann Robert Koch and continued his tubercle bacillus research. In the same year, he became a French citizen.
He and Roux identified a toxin released by the diphtheria bacillus (bacteria) in 1889, demonstrating that the toxin, not the germ, was the primary cause of the disease.
He worked as a surgeon aboard steamships off the coast of French Indochina in 1890. This was the start of his four-year journey through Southeast Asia’s center area.
He went to Hong Kong in 1894 to look into the Manchurian Pneumonic Plague pandemic. He found the pathogen that causes plague while in Hong Kong. Dr. Kitasato Shibasabur had discovered a disease-causing microbe just a few days before in Hong Kong.
For the first time in history, Yersin was able to show that the same bacillus was present in both mice and humans, revealing the disease’s likely mode of transmission.
In 1895, he returned to the Institute Pasteur in Paris, where he collaborated with Émile Roux, Albert Calmette, and Amédée Borrel to create the first anti-plague serum. He returned to Indochina later that year and constructed a tiny laboratory in Nha Trang to make the serum. Later, the laboratory was absorbed into the Pasteur Institute.
He continued his research on the bubonic plague from 1895 to 1897. In 1896, he tested the serum he obtained from Paris in Canton and Amoy, and in 1897, he tried it in Bombay, India, but the results were poor.
He chose to make Indochina his permanent home and became actively involved in medical research. In 1902, he assisted in the founding of Hanoi Medical University and served as the institute’s first medical director for the next two years.
Meanwhile, in order to fund the Nha Trang laboratory, he turned to agriculture and began cultivating rubber trees imported from Brazil. He grew corn (maize), rice, and coffee as well. He attempted to cultivate the quinine tree imported from South America in Honda in 1915, as quinine had malaria-curing powers.
He was appointed Honorary Director and member of the Pasteur Institute’s Board of Administration in 1934.
Yersin’s Major Projects
He discovered the pathogen that causes plague in 1894. In his honor, it is currently known as ‘Yersinia pestis.’ He established that the same bacillus was present in both rodents and humans, leading to the identification of the disease’s likely carrier.
Achievements and Awards
The bubonic plague bacillus he discovered was given the name ‘Yersinia pestis’ in his honor. In 1927, he was awarded the Leconte Prize in appreciation of his significant discovery.
Paul Doumer, the then Governor-General of French Indochina, named him the first Headmaster of Hanoi Medical University on January 8, 1902.
After Indochina gained independence, streets named after him were preserved.
The ‘Yersin Museum’ has been established in his home in Nha Trang.
In his honor, a private university in Da Lat named ‘Yersin University was established in 2004.
Personal History and Legacy
During World War II, he died at his home in Nha Trang, Vietnam, on March 1, 1943. A pagoda has been built over his burial at Suoi Dau, where ceremonies are performed. “Benefactor and humanist, venerated by the Vietnamese people,” reads the epitaph on his tombstone.
The Vietnamese call him ‘ng Năm’ because of his tremendous commitment to public health.
Estimated Net worth