Monday, April 30, 2012

Louis Pasteur, Inventer of Vaccine.


 
Louis Pasteur, Inventpr of Vaccine.
Dr. Dwijesh Kumar Panda, M.D, Ph.D ( Medicine)

Louis Pasteur was a French  chemist and Microbiologist. He is remembered for his  remarkable  breakthroughs  in the causes and prevention  of diseases. His discoveries reduced mortality from puerperal fever, and he created the first vaccines for rabies and anthranx. His experiments supported the germ theory of disease. He was best known to the general public for inventing a method to stop milk and wine from causing  sickness , a process that came to be called Pasteurisation.
Early life :-  Louis Pasteur was born on December 27, 1822 in France into the family of a poor tanner. He had five children, only two of whom survived to adulthood, the other three died of Typhoid. These personal tragedies inspired Pasteur to try to find cures for diseases such as typhoid.
Germ theory of disease;-  Pasteur demonstrated  fermentation  which is  caused by the growth of micro-organisms , and the emergent growth of bacteria in nutrient broths is not due to spontaneous generation, but rather to biogenesis (“all life is from life”). He is often regarded as the father of germ theory and bacteriology, together with Robert Koch. His research also showed the growth of micro-organisms responsible for spoiling beverages, such as beer, wine and milk. He invented a process in which liquids such as milk were heated to kill most bacteria present in them. This process was known as “Pasteurization”. Beverages contamination led Pasteur to the idea that  micro-organisms infecting animals and humans cause disease. Pasteur also discovered anaerobiasis where by some micro-organisms develop and live without air or oxygen called Pasteur effect.
Immunology and Vaccination :-  In the 1870s Pasteur claimed that he had the Anthrax vaccine by exposing the bacilli to oxygen. Anthrax is a disease which affects the cattle. Edward  Jenner had discovered vaccination using cowpox to give cross immunity to smallpox in 1796. Pasteur had replaced the use of actual  smallpox material in inoculation. This discovery revolutionized work in  infectious diseases and Pasteur gave these artificially weakened diseases the generic name of “Vaccine”. Pasteur  produced the first vaccine for rabies by growing the virus in rabbits, and then weakening it by drying the affected nerve tissue. The vaccine was first used on a 9 year  old boy in 1985 after the boy was badly mauled by a rabid dog. This was done at some personal risk for Pasteur, since he was not a licenced physician and could have faced prosecution for treating the boy. The body did not  contract the disease. Pasteur saved the boy’s life. He was hailed as a hero and the legal matter was not pursued. The treatment’s success laid the foundation stone for the manufacture of many other vaccines. Pasteur was absolutely  fearless. Anxious to secure a sample of saliva straight from the jaws of a rabid  dog with the glass tube held between his lips proves a sign of his bravery.
Vaccination ;-  It is the administration of antigenic material to stimulate the immune  system of an individual to develop adaptive immunity to a disease. The active agent of a vaccine may be intact but inactivated (non-infective ) or attenuated ( with reduced infectivity ) forms of the causative pathogens. The word vaccination was first used by Edward  Jenner in 1796. Louis Pasteur furthered the concept through his pioneering work in microbiology. The vaccine triggers an immune response more  rapidly than the natural infection itself.
              All vaccinations work by presenting a foreign anigen to the immune system in order to evoke an immune response. The main types used in clinical use are as follows
1.       An inactivated vaccine consists of virus or bacteria which are grown in culture and then killed by heat or formaldehyde. Thus the bacterial particles are destroyed  and can not replicate.
2.       An attenuated vaccine, live virus or bacteria with very low virulence are administered. They will replicate very slowly.
These vaccines are produced by adapting a virus into different host cell cultures.Those vaccines can not be used in immunocompromised individuals.
                Having worked on bacterial diseases, Louis Pasteur became so famous that money poured into the institute named after him. He continued his work at the Pasteur Institute for the rest of his life. Thanks to Pasteur, we now understand how infectious diseases are spread, and through vaccination doctors have been able to save countless human lives in the twentieth century.

                                   

REFERENCES:-
1.Top. Microbiol.Immunol. Current topics.
2.Vaccine Overview-2008-01-02
3.” Doctors and diagnosis “.
4. The Lancet- Feb. 2010.
Dr. Dwijesh Kumar Panda, M.D.,Ph.D (Medicine)
                                                                M5/12, Acharya Vihar, Bhubaneswar, 751 013
                                                                Contact No. 094384 70777.
Submitted to the Secretary, Odisha Bigyan Academy, Bhubaneswar for favour of publication. E.Mail- secretaryoba@yahoo.com