Germ Theory of Disease

ntroduction

• Germ theory states that specific microscopic organisms are the cause of specific diseases.
  
• Germ theory is also called the pathogenic theory of medicine.
  
• Germ theory led in to the development of antibiotics and hygienic practices.
  
• It is considered as the cornerstone of modern medicine and clinical microbiology.
  
• Major contributors to germ theory are:
  
  • Antoni van Leeuwenhoek
  • Francesco Redi
  • Rudolf Virchow
  • Louis Pasteur
  • Joseph Lister
  • Robert Koch

Terms

• Microbes, or microorganisms - minute living things that are usually unable to be viewed with the naked eye.
  
• Germ - refers to a rapidly growing cell.
  
• Spontaneous generation - the hypothesis that living organisms arise from nonliving matter. It was an important early development in the germ theory.
  
• Biogenesis:  living cells can arise only from preexisting cells.
  
• Antibiotics - chemicals produced by bacteria and fungi that inhibit or kill other microbes.

Antoni van Leeuwenhoek (1673-1723)

• Microorganisms were first directly observed by Antoni van Leeuwenhoek, who is considered the father of microbiology.
  

Edward Jenner

• In 1796, Edward Jenner inoculated a person with cowpox virus.

Agostino Bassi (1835)

• Agostino Bassi showed a silkworm disease was caused by a fungus.

Ignaz Semmelwise (1840)

• He advocated hand washing to prevent transmission of puerperal fever from one patient to another.

Louis Pasteur

• Louis Pasteur was one of the first to link germs to disease.
  
• In 1861, Louis Pasteur demonstrated that microorganisms are present in the air.
  
• Pasteur discovered vaccines for chicken cholera. (1880), Anthrax (1881) and Rabies (1885).
  
• Pasteur also showed that microbes are responsible for fermentation.
  

Joseph Lister

• Joseph Lister is considered as inventor of antiseptic surgical techniques.
  
• In 1860s, Joseph Lister used a chemical disinfectant to prevent surgical wound infections.
  

Robert Koch

• In 1876, Robert Koch explained a bacterium causes anthrax.
  
• In 1882, he discovered the germ that caused tuberculosis. (TB)
  
• In 1883, he discovered the germ that caused cholera.
  

Alexander Fleming

• In 1928, Alexander Fleming discovered the first antibiotic from Penicillium fungus.

References

1. "The History of the Germ Theory". The British Medical Journal 1 (1415): 312. 1888.
   
2. Germ Theory in Contagion: Historical Views of Diseases and Epidemics. Harvard University Library; accessed on 8/9/2011. Available at http://ocp.hul.harvard.edu/contagion/germtheory.html