Louis Pasteur

Louis Pasteur (December 27 1822 – September 28 1895) was a French microbiologist and chemist. He is known to the general public for his demonstration of the germ theory of disease and his development techniques of inoculation, most notably the first vaccine against rabies; however, he also made a major discovery in the field of chemistry, regarding asymmetric molecules and the polarization of light.

Immunology

His later work on diseases included work on chicken cholera. During this work, a culture of the responsible bacteria had spoiled and failed to induce the disease in some chickens he was infecting with the disease. Upon reusing these healthy chickens, Pasteur discovered that he could not infect them, even with fresh bacteria: the weakened bacteria had caused the chickens to become immune to the disease, although they had not actually caused the disease.

Related Topics:
Cholera - Bacteria - Chicken - Immune

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This discovery was an accident. His assistant Charles Chamberland had been instructed to innocuate the chickens after Pasteur went on holiday. Chamberland failed to do this but instead went on holiday himself. On his return the month old cultures made the chickens unwell but instead of the infection being fatal as usual the chickens recovered completely. Chamberland assumed that an error had been made, and wanted to discard the apparently faulty culture out when Pasteur stopped him. Pasteur guessed that the recovered animals now might be immune to the disease as were the animals at Eure-et-Loir that had recovered from anthrax.

Related Topics:
Charles Chamberland - Eure-et-Loir

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In the 1870s he applied this immunization method to anthrax, which affected cattle, and aroused interest in combating other diseases.

Related Topics:
1870s - Anthrax - Cattle

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Pasteur publicaly claimed that he had made the anthrax vaccine by exposing the bacilus to oxygen. His laboratory notebooks now in the Bibliotheque Nationale in Paris in fact show that Pasteur used the method of a rival Jean-Joseph-Henri Toussaint, a Toulouse veterinary surgeon to create the anthrax vaccine. This method used the oxidizing agent potassium dichromate. Pasteur's oxygen method did eventually produce a vaccine but only after he had been awarded a patent on the production of an anthrax vaccine.

Related Topics:
Bibliotheque Nationale - Paris - Jean-Joseph-Henri Toussaint - Toulouse - Veterinary surgeon - Potassium dichromate - Patent

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The notion of a weak form of a disease causing immunity to the virulent version was not new: this had been known for a long time for smallpox. Inoculation with smallpox was known to result in far less scarring and greatly reduced mortality than with the naturally acquired disease. Edward Jenner had also discovered vaccination, using cowpox to give cross-immunity to smallpox, and by Pasteur's time this had generally replaced the use of actual smallpox material in inoculation. The difference with chicken cholera and anthrax was that the weakened form of the disease organism had been generated artificially, and so a naturally weak form of the disease organism did not need to be found.

Related Topics:
Smallpox - Edward Jenner - Vaccination - Cowpox

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This discovery revolutionised work in infectious diseases, and Pasteur gave these artificially weakened diseases the generic name of vaccines, to honour Jenner's discovery. Pasteur produced the first vaccine for rabies by growing the virus in rabbits and then weakening it by drying the affected nerve tissue.

Related Topics:
Vaccine - Rabies

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The rabies vaccine was initially created by Emile Roux, a French doctor and a collegue of Pasteur who had been working with a killed vaccine produced by desiccating the spinal cords of infected rabbits. The vaccine had only been tested in 11 dogs before its first human trial.

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This vaccine was first used on 9-year old Joseph Meister on July 6, 1885 after the boy was badly mauled by a rabid dog. This was done at some personal risk for Pasteur, since he was not a licensed physician and could have faced prosecution for treating the boy. Fortunately, the treatment proved to be a spectacular success, with Meister avoiding the disease; thus, Pasteur was hailed as a hero and the legal matter was not pursued. The treatment's success laid the foundations for the manufacture of many other vaccines. The first of the Pasteur Institutes was also built on the basis of this achievement.

Related Topics:
Joseph Meister - July 6 - 1885 - Pasteur Institute

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