The document outlines the history and discovery of viruses, starting from the definition of a virus as an infectious agent that replicates inside living cells. Key milestones include the invention of the Chamberland filter, the identification of the tobacco mosaic virus, and the discovery of bacteriophages, marking significant advancements in virology. The mid-20th century is noted as a golden age for virus discovery, with various methods developed for culturing viruses and the introduction of electron microscopy for visualizing them.

1. VIRUS
K.Rajani D.L in Microbiology

2. DISCOVERY OF VIRUS
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3. DEFINITION
Virus is an infectious agent which
replicate only inside the living cells.
• Virus is considered as the edge of organisms at the
edge of the life. In later discussion we will get
complete information regarding this statement..
• The term VIRUS was coined by the scientist Louis
Pasteur.
• Up to 19th century ending people believed that so many
diseases such as smallpox are caused because of the
curse of God.
• . In 1884 Chamberland invented a filter called Porcelain
filter which cannot allow even bacteria to pass through
it.
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4. 4
• This filter in later days called as chamberland filter which became
a big tool for the isolation of virus.
• In 1892 A scientist Dimitri Ivanovsky stated that there is very
small infectious agent which is smaller than bacteria and is
passing even through chamberland filter and causing disease to
healthy tobacco plant.
• In 1898 Another scientist Martinus Beijerinck worked on the same
disease causative agent and he called it Contagium Vivum
Fluidum means soluble living germ and later he also coined
the term VIRUS and the virus causing the mosaic disease in
tobacco plant is named as Tobacco Mosaic Virus(TMV).
DISCOVERY

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• Martinus Beijerink is later called as Father of Virology.
• In the same year Freidrich Loffler& Paul Frosch discovered
animal virus using Chamberland filter which is Apthovirus
causes Foot and Mouth disease.
DISCOVERY

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DISCOVERY
• Fredrick Twort and F.d’Herelle discovered
bacteriophages(viruses those infects bacteria) individually and
they stated that “a highly diluted material having capacity to lyse
bacterial colonies is destroying the bacterial colonies and is
passing through one colony to other and causing lysis. But after
the heating of that filtrate the lytic property is destroyed”. This
phenomena is also called as Twort and F.d’Herelle
phenomena.
• Up to end of 19th century scientist grown virus either in plants or
in animals.

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K.RAJANID.L IN MICROBIOLOGY
• Mid of the 20th centuryis known as the Golden age for virus
discovery. So many of the following viruses are discovered.
• Retro viruses
• Hepatitis-B virus
• Hepatitis-C virus etc.
DISCOVERY

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K.RAJANI D.L IN MICROBIOLOGY
• But from 1906 so many scientist identified different ways such as tissue cultures,
culturing in chick embryo like that.
• The images of viruses are introduced to world after the invention of electron
microscope.
• A scientist W.M.Stanley for the first time stated that TMV is mostly made up of
protein.
• Some other viruses are discovered by different scientist given below.
• Mycoviruses- Hollings
• Cyanophages- Safferman and Morris.
• Satillitevirus- Kassanis
• Viroids- Diener&Raymer
• Prion- Prusiner
• HIV- Luc Montaginer.
DISCOVERY

9. THANK YOU!
K.RAJANI
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NOTES