Louis Pasteur and Rabies

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Chea Takihiro English l ភាសាខ្មែរ

Few people in Cambodia are unfamiliar with Louis Pasteur. While many know the Institut Pasteur simply by its informal moniker “Pasteur Hospital”—a familiar landmark where people receive vaccinations after animal bites, especially from dogs or cats—Cambodians intimately understand how terrifying rabies is and the excruciating suffering it inflicts upon its victims. Louis Pasteur was the pioneer who discovered the first vaccine against rabies in human history.

Moreover, the Institut Pasteur stands as a vital center for scientific research, education, and training, nurturing young scientists, physicians, and researchers from all corners of the globe to become the next generation in the fight against infectious diseases. During Cambodia’s outbreak of COVID-19, this institute served as a crucial testing hub to detect this formidable virus.

For my part, I wish to express my deepest gratitude to Pasteur, even though he passed away long ago. This is because my own daughter received rabies vaccination and medical monitoring following a scratch from a monkey. I truly believe that through the tireless efforts of the Institut Pasteur, rabies has been mitigated to the greatest extent possible in Cambodia.

Louis Pasteur was born on December 27, 1822, in Dole, France. His father, Jean-Joseph Pasteur, was a former soldier under Emperor Napoleon and a tanner.Pasteur was a French chemist and physicist whose early research focused on the crystalline structures of chemical substances—specifically exploring how molecular structures combine in space, as seen in his discovery of the structural differences in tartaric acid. It almost feels like a historical coincidence that Pasteur initially had little interest or focus on biology.

Pasteur served as the head of the scientific research laboratory at the École Normale Supérieure (ENS) in Paris, one of France’s most prestigious public universities. He established his own private laboratory called the Laboratoire de la Rue d’Ulm within the school’s grounds. Although this laboratory was located in a public institution, Pasteur maintained complete autonomy and freedom in choosing his research topics.

In 1856, a wine manufacturer in Lille enlisted his help to solve a major crisis for his enterprise: the wine he brewed and fermented using traditional methods kept turning sour and spoiling. The manufacturer wanted Pasteur to identify the root cause of the spoilage and find a solution.

Examining samples under a microscope, Pasteur discovered that round yeast cells were responsible for producing good alcohol, whereas rod-shaped bacteria were the culprits making the wine sour. Pasteur provided a solution to eliminate those harmful bacteria: he heated the finished wine to a temperature of about 55°C to 60°C for a short duration. He found that the harmful bacteria were destroyed without damaging the beneficial yeast or compromising the quality of the wine. This solution completely saved the wine industry of that era. His technique was subsequently adopted widely for eliminating harmful microorganisms in milk, various processed fruit juices, and beer. In honor of his dedication and brilliant achievement, this sanitation technique was named Pasteurization.

In the mid-19th century, the silk production industry in southern France (particularly in the region of Alès) was one of the most vital economic lifelines for tens of thousands of farming families. However, beginning in 1845, a mysterious disease severely devastated silkworms. The silkworms developed dark, pepper-like spots on their skin and died by the millions before they could spin cocoons. French silk production plummeted from 26 million kilograms down to a mere 4 million kilograms. Countless silk farms were forced to close, and the economy of southern France faced total collapse.

Due to the worsening situation, the French government—under the leadership of Emperor Napoleon III—commissioned Jean-Baptiste Dumas, Pasteur’s former mentor and a senator, to invite Pasteur to help resolve the crisis. When presented with the request, Pasteur initially hesitated and declined, saying:

“I have never even held or seen a silkworm in my life! How can I possibly help solve silkworm disease?”

However, Dumas replied:

“That is precisely the point! Because you have no old prejudices, you will see it with a truly scientific eye.”

Out of respect for his mentor and his duty to the nation, Pasteur accepted the mission and moved to the city of Alès in 1865.

Pasteur spent nearly five years (1865–1869) on-site at a farm, examining silkworms, moths, and their eggs in meticulous detail under a microscope. He discovered that silkworms were not suffering from just a single affliction, but rather two distinct diseases striking simultaneously:

1. Pébrine: A disease characterized by dark, pepper-like spots on the skin, caused by a micro-parasite (known today as Nosema bombycis). This parasite could be transmitted from a mother moth to her offspring’s eggs.
2. Flacherie: A rotting disease of the silkworm’s digestive tract, caused by bacteria when silkworms ate unclean mulberry leaves or lived in excessively humid environments.

Once he understood the root causes of these diseases, Pasteur developed a simple yet 100% effective prevention method: after a female moth laid its eggs, the moth had to be ground up and examined under a microscope. If “parasite spores” were detected in the mother moth, it meant her eggs were also infected, and those moths and eggs had to be burned and destroyed immediately. Only eggs originating from disease-free moths were kept for farmers to raise.

This method completely halted the transmission of the disease from generation to generation, reviving the silk industries of both France and Italy. It served as the ultimate proof that microscopic organisms invisible to the naked eye were the culprits behind diseases in living creatures, and that these germs could be transmitted through air, food, and lineage.

This experience drew Pasteur away from his original domains of chemistry and physics, transforming him into a biologist. Perhaps because farmers lacked scientific knowledge and desperately needed his guidance in both science and biology, he could not turn back to his previous specialization. Moreover, he integrated chemical and physical techniques to pave the way toward effective vaccines for infectious diseases—opening a groundbreaking new chapter in modern science.

In the late 19th century, the poultry farming industry in France was facing severe threats from chicken cholera (Chicken cholera). This disease was caused by a virulent bacterium (known today as Pasteurella multocida), which caused chickens to droop, vomit mucus, and die by the millions within just a few days. The French government and farmers urged Louis Pasteur and his team (including Émile Roux and Charles Chamberland) to continue finding solutions to save animal farms. As expected, Pasteur and his team accepted the proposal and enthusiastically began studying and researching the disease.

In the summer of 1879, before leaving his laboratory for a summer vacation, Pasteur instructed his assistants to properly store the pathogen samples. He also left some samples exposed to light and airflow, wanting to observe how those pathogen samples would change during the vacation. True to his intuition, due to the intense summer heat, the bacteria in those glass flasks suffered damage and progressively lost their virulence.

Pasteur recalled the methodology of English physician Edward Jenner, who discovered the smallpox vaccine in 1896 (historical note: 1796) by using milder cowpox to protect humans. Pasteur decided to test the “long-abandoned, aged” bacteria by injecting them into chickens.

As a result, those chickens only experienced mild symptoms (drowsiness and a loss of appetite) but did not die. Suspecting those chickens had developed immunity, Pasteur decided to inject them a second time with “fresh, highly virulent bacteria,” along with a fresh batch of chickens that had never been vaccinated before. The results of this experiment astonished the world:

• The new chickens (newly introduced) died rapidly from chicken cholera.
• The old chickens (previously given the weakened bacteria) remained perfectly healthy, walked around feeding, and did not contract the disease at all!

To commemorate this magnificent discovery, Louis Pasteur decided to officially adopt the word “Vaccine” (derived from the Latin word Vacca, meaning cow) for any attenuated substance or pathogen injected to prevent disease. This terminology honored and remembered Dr. Edward Jenner, who was the first to use a mild virus from cows to protect humans against smallpox.

Louis Pasteur and his team successfully saved and conquered numerous animal diseases, most of which were severe epidemics—diseases that spread rapidly and carried extremely high mortality rates. These included:

1. Silkworm diseases (Pébrine & Flacherie) – 1865
2. Anthrax (affecting sheep and cattle) – 1881
3. Swine Erysipelas – 1882

Finally came the most precious discovery for humanity: the rabies vaccine. In his childhood, Pasteur had witnessed a horrifying tragedy when a rabid wolf attacked villagers. The victims bitten by the wolf were subjected to a brutal treatment method: red-hot irons were pressed directly onto their bite wounds. Ultimately, the patients still could not be saved. Before passing away, the victims suffered excruciating agony.

One of the reasons that drove Pasteur to relentlessly search for a rabies treatment was that at the time, no one could cure the disease yet. This meant that everyone who contracted rabies would inevitably die a painful death. His own bitter history also fueled his determination to accomplish this monumental task.

Pasteur began his study by focusing exclusively on curing dogs infected with rabies, adopting the methodology used for the chicken cholera vaccine by weakening the pathogen’s virulence. His team successfully experimented on dogs by injecting viruses that had been weakened until they lost their pathogenic capability. He injected progressively increasing doses daily for 10 days; the dog’s condition gradually improved, and on the final day, he injected a fully potent, virulent virus—and the dog recovered completely.

To step back slightly: in 1848, while serving as a professor of chemistry at the University of Strasbourg, Pasteur met and fell in love with Mademoiselle Marie Laurent, the daughter of the university’s rector. They were married on May 29, 1849.

Marie was not only a wife but also a life partner and one of the most loyal assistants in his scientific endeavors. She helped record experimental notes, write official letters, and tenderly care for Pasteur’s health. As the fruit of their marriage, Pasteur and his wife had five children. However, fate did not grant continuous happiness to their family. The tragedy that caused Pasteur the deepest pain and sorrow was the loss of three of their children to typhoid fever (Typhoid Fever):

• Eldest daughter Jeanne passed away in 1859 at age 9.
• Third daughter Camille passed away in 1865 at age 2.
• Fifth daughter Cécile passed away in 1866 at age 12.

Only two children survived to adulthood: their son Jean-Baptiste and daughter Marie-Louise. The loss of his three daughters to infectious diseases that lacked any medical treatment at the time left deep emotional scars and served as the greatest driving force behind Pasteur’s vow to conquer infectious microbes.

The Story of Saving Young Joseph Meister (1885)

In July 1885, a 9-year-old French boy named Joseph Meister was brutally mauled in 14 places across his body by a rabid dog. At that time, anyone bitten by a rabid dog faced a 100% death rate accompanied by excruciating agony. Joseph’s mother decided to bring him to Louis Pasteur to seek a final glimmer of hope.

At that moment, Pasteur was in deep psychological turmoil because his vaccine had never been tested on a human before (having only been tested on dogs). Furthermore, Pasteur was not a medical doctor treating humans (he was a chemist and microbiologist), meaning administering the injection to a human could lead to legal prosecution if the child died during his treatment process.

These two doctors took full personal responsibility for administering the vaccine injections to young Joseph directly.Pasteur administered the newly discovered vaccine—which had never been tested on humans before—to young Joseph over a period of 10 days, totaling 13 injections. With each dose, he progressively increased the concentration and strength of the pathogen, culminating in the final injection which used a rabies virus strain strong enough to kill an animal instantly.

Joseph’s condition improved gradually until the boy completely recovered without showing any symptoms of rabies. Joseph survived into adulthood and even became a doorman at the Pasteur Institute to express his heartfelt gratitude to Louis Pasteur.

Vaccination is extremely effective because the vaccine itself does not directly fight the rabies virus. The true defenders are the antibodies within our bodies. Normally, when a pathogen enters our system, our antibodies fight back immediately, especially against viruses our body has previously encountered. However, when faced with a new pathogen our body has never met, it needs time to study how to eliminate it. Therefore, receiving a vaccination (using a weakened pathogen that lacks harmful capability) is the best preventative method. A weakened pathogen acts like a photograph of a criminal, allowing antibodies—acting like police—to clearly recognize the criminal’s face and know how to fight back when encountering the real criminal directly.

Never Give Up

You have read the complete summary story of Louis Pasteur. He lived an ordinary life, possessing 24 hours in a day just like us. He had a family, experienced love, and witnessed sorrow and empathy. He faced problems, worked in teams to find solutions, and learned from his experiences.

Do you think a chemist stepping into agriculture and eventually curing deadly human diseases faced no criticism? Pasteur’s fiercest opponents were none other than the French medical association itself. Especially after he published the “Germ Theory,” doctors at the time refused to believe that tiny bacteria invisible to the naked eye could kill human beings; they believed diseases simply occurred spontaneously.

The “Germ Theory” recommended that doctors wash their hands or wear gloves during patient treatment and sterilize medical instruments by boiling them, as those materials acted as vectors for disease transmission. This theory met fierce resistance from some physicians. The most striking opposition occurred during the vaccination treatment of young Joseph, forcing Pasteur to seek help from expert physicians to administer the injections for him. The doctors opposed to Pasteur branded his treatment a “brutal torture” because he was injecting rabies virus into a 9-year-old child. Such opposition perhaps stemmed from the fact that he lacked a formal degree in medicine or biology.

From this, we learn that support will eventually prevail once we discover sufficient, trustworthy evidence. Despite opposition from certain doctors, other physicians strongly supported his actions.

Pasteur did not give up. In 1868 (at the age of 45), Pasteur suffered a severe stroke that left the left side of his body paralyzed for life. However, his mind and spirit remained brilliantly sharp and active. He did not allow his half-paralyzed body to become an obstacle to his research. The vaccines that saved pig, cattle, and goat farms, as well as the rabies vaccine, were all discovered and perfected despite his physical disability.

As Louis Pasteur famously stated:

“Chance favors only the prepared mind.”

Throughout the lifetime of Louis Pasteur, he was honored and received many high-level medals from international institutions:

• Légion d’Honneur (Grand Cross): The highest honorary decoration of France, awarded by the French government for his service to the nation and humanity.
• Copley Medal (1874): Awarded by the Royal Society of London for his remarkable research on fermentation and bacteria processes.
• Rumford Medal (1856 & 1892): Received twice from the Royal Society of London for significant discoveries in chemistry and light.
• Leeuwenhoek Medal (1895): Awarded by the Royal Netherlands Academy of Arts and Sciences. This medal is the world’s highest award in microbiology, presented only once every 10 years to a single individual.
• Montyon Prizes: Received multiple times from the French Academy of Sciences for medical research and scientific experiments.

The Pasteur Institute

The Pasteur Institute was officially established on June 4, 1887, and opened to operations on November 14, 1888, in Paris, France. Following Pasteur’s successful creation of the first rabies vaccine, people from around the world sent letters and substantial funds (International Public Subscription) to help him establish this research center. Louis Pasteur served directly as the president of the institute until his passing in 1895.

Since its inception, the Pasteur Institute has adhered firmly to three core pillars of mission:

1. Scientific & Biomedical Research: Conducting deep research on pathogens, viruses, bacteria, and infectious diseases to develop vaccines, diagnostic methods, and new therapeutic drugs (such as the discovery of the HIV virus in 1983 by scientists at the Pasteur Institute).
2. Public Health: Administering vaccines and preventing the outbreak of severe infectious diseases worldwide through the Pasteur Network, which comprises over 30 institutions in various countries (including the Institut Pasteur du Cambodge).
3. Education and Training: Training young scientists, physicians, and researchers from all over the world to become the next generation in the fight against infectious diseases.

The Institut Pasteur du Cambodge

The Institut Pasteur du Cambodge was originally established in 1953 and resumed active operations in 1995 under an agreement between the Royal Government of Cambodia and the Pasteur Institute in Paris. The institution has three core missions: scientific research on infectious diseases (Research), public health (Public Health), and education (Education).

During the COVID-19 pandemic, this institute was the very first place to detect and confirm the diagnosis of the first COVID-19 case in Cambodia (on January 27, 2020). However, back in 2010, researchers from the Institute Pasteur du Cambodge, in collaboration with an international project, collected samples from the bat species Rhinolophus shameli in Stung Treng province. Subsequently, those samples were meticulously preserved in a “Biobank” inside an ultra-low temperature freezer at −80°C in Phnom Penh.

According to international scientific research reports published in the world medical journal Nature Communications and studies by Dr. Veasna Duong and Dr. Erik Karlsson, extracting coronavirus samples RshST73 and RshST74 from the sample bank in Cambodia for full genome sequencing (Full Genome Sequencing) provided an invaluable comparative benchmark: a 92.6% genetic similarity with SARS-CoV-2. This has enabled the global scientific community to determine the evolutionary origins of the virus, understand the invariant regions of the Spike Protein, and establish a foundational database for developers of mRNA vaccines and pan-coronavirus vaccines (Pan-Coronavirus Vaccines) to prepare against future epidemic outbreaks.

Note:

This text has been verified and sourced by Artificial Intelligence (AI).

📚 References & Historical Sources:

1. Louis Pasteur’s Biography and Scientific Works:
   • Vallery-Radot, René. The Life of Pasteur. (Official biography and records of Pasteur’s research on chicken cholera, anthrax, and the rabies vaccine 1879–1885).
   • Geison, Gerald L. The Private Science of Louis Pasteur. Princeton University Press. (Detailed analysis of laboratory experiments and professional friction with the French medical establishment).
   • Pasteur Institute Historical Archives regarding the treatment of young Joseph Meister in 1885.
2. History of Early Vaccination (Edward Jenner):
   • The College of Physicians of Philadelphia. History of Vaccines — Edward Jenner and Smallpox Vaccination (1796).
3. History and Mission of the Pasteur Institute:
   • Official documentation of the Pasteur Network regarding its three core mission pillars (Biomedical Research, Public Health, and Education & Training).
   • Global medical records on the initial discovery of the HIV virus in 1983 by scientists at the Pasteur Institute.

4. Institut Pasteur du Cambodge (IPC) and Coronavirus Research:

• Public health reports and official data from the Institut Pasteur du Cambodge concerning the detection and clinical diagnosis of Cambodia’s first COVID-19 case on January 27, 2020.
• International collaborative research and sample collection from the bat species Rhinolophus shameli in Stung Treng province in 2010, preserved in the Biobank at −80°C in Phnom Penh.
• International medical journal Nature Communications and studies led by Dr. Veasna Duong and Dr. Erik Karlsson on the full genome sequencing of coronaviruses RshST73 and RshST74, demonstrating a 92.6% genetic similarity to SARS-CoV-2 as a foundational database for developing Pan-Coronavirus Vaccines.