Uploaded by gamervinayak183

Bio PPT- Virus

By Vinayak
What is a virus?
● A virus is an infectious
microbe that contains
genetic material (either
DNA or RNA) and
surrounded by a protein
coat (Capsid).
● A virus cannot replicate
alone; instead, it must
infect cells and use
components of the host cell
to make copies of itself.
The discovery of a virus
• Two scientists were accredited for the discovery of the Virus,
Dmitri Ivanovsky
• Ivanovsky reported in 1892 that extracts from infected leaves
were still infectious after filtration through a Chamberland filtercandle.
• Beijerinck, in 1898, was the first to coin the term 'virus', the
cause of the tobacco mosaic. He showed that the pathogen was
able to migrate in an agar gel, therefore being an infectious
soluble agent, or a 'contagium vivum fluidum' and definitively
not a 'contagium fixum' as would be a bacteria.
• Beijerinck is also called the father of virology due to his
Types of Viruses
Are there viruses that infect other viruses?
• Yes
• There are viruses that infect
other viruses.
• These are called Virophages &
only infect a special, rare group
called Giant Viruses
• Giant viruses are viruses that
have a diameter of more than
600 nanometer.
How does a vaccine work?
• A simple, safe, & effective way of
protecting you against harmful diseases,
before you come into contact with them.
• They train your immune system to create
antibodies for a particular disease.
• They contain only killed or weakened
forms of germs like viruses or bacteria,
they do not cause the disease or put you
at risk of its complications.
The early vaccine
• Edward Jenner is considered the
founder of vaccinology in 1796, after
he inoculated a 13 year-old-boy with
vaccinia virus (cowpox), and
demonstrated immunity to smallpox.
• In 1798, the first smallpox vaccine was
• However, a practice wherein monks
drink snake venom to gain immunity to
it, was followed centuries before
COVID - 19
• Covid 19’s full form is Coronavirus
Disease and is caused by the
SARS-COV2 virus
• COVID-19 affects different people
in different ways.
• Most infected people will develop
mild to moderate illness and
recover without hospitalization.