Transcript CHARACTERISTICS OF VIRUSES

History of viruses

Viruses have been around
for a long time, but only
recently have we gained
the ability to investigate
what they look like.
Understanding Viruses
History of
Viruses
History of Viruses
Edward Jenner (1798)
Infected patients with
cowpox (Vaccinia) virus,
giving them immunity to
smallpox = first vaccine
Smallpox has been
eradicated from the
3 world today.
History of Viruses
Dmitri Ivanovsky (1892)
Showed that the infectious
agent that causes Tobacco
Mosaic Disease could pass
through filters known to
stop bacteria.
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History of Viruses
“Spanish flu” pandemic (1892)
Extremely virulent form of
the flu that killed an
estimated 20 – 50 million
people around the world.
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History of Viruses
1930s
Development of the
electron microscope
provides allows
scientists to view
microscopic objects at
extreme magnification.
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Tobacco Mosaic Virus
Wendell Stanley
(1935) discovered
viruses were made
of nucleic acid and
protein
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History of Viruses
1950 - 1960
Development and use
of the Salk (killed)
and Sabin (live) polio
vaccines in the US
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History of Viruses
1976
Outbreak of hemorrhagic
fever in Sudan and Zaire.
Virus is named after the
Ebola River, where the
first cases were believed
to originate.
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History of Viruses
Early 1980s
AIDS is recognized
as a new human
disease caused by a
retrovirus known as
HIV.
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History of Viruses
“Swine flu” pandemic (2009)
A new H1N1 influenza virus
of swine origin begins
infecting people in Mexico
before spreading to over
200 countries around the
world.
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Herpes Virus (DNA)
SIMPLEX I and II
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Rhinovirus (RNA)
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COMMON COLD
Influenza Virus (RNA)
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Chickenpox Virus (DNA)
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Papillomavirus – Warts! (DNA)
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HIV – (Retrovirus)
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HOST SPECIFICITY
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All kingdoms can be infected by viruses
Viruses are kingdom specific but they may or may
not be species specific
Spread is specific to the type of virus
PARASITISM

Viruses are parasites.
–
A parasite is an organism that depends upon
another living organism for its existence in
such a way that it harms that organism.
Vaccine

Is most often a weakened or inactivated form
of the virus
–
To expose your immune system to the virus which
will allow your body to better fight off the more
virulent form of the virus if your body is exposed to it
again in the future.
Vector Control
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This is controlling the vectors that are
carrying the virus.
Examples:
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We stay home when sick, cover our mouth when
we cough etc.
We control the mosquito population in order to
control the West Nile virus
Other Drug Treatments
Specific
viruses.
to certain
They
don’t cure the virus
but they can slow down
and inhibit the
multiplication of the virus.
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Reducing the Risk
Most viruses can’t be treated, but
they can be prevented!
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Cover mouth/nose when you sneeze of
cough
Wash hands frequently
Avoid contact with the body fluids
Not foolproof but reduces the risks