Introduction to Virology
25 December 2020 19:27
Introduction
Why study Viruses?
One main motivation for the study of viruses is the fact that they cause many
important infectious diseases, among them the common cold, influenza,
rabies, measles etc.
Once we understand their structure and how they cause disease we can then
design drugs to target viral infections. Viruses can be used for gene therapy,
vaccines and diagnosis.
➢ New viruses arise at any time
➢ Prevent and cure infection (vaccines, drugs)
➢ Control biological pests
➢ Treatment for cancers
➢ Help understanding of cells
How might you discover a virus?
Immuno-fluorescent assay
Antibody testing
Electron microscopy
How might virus have been discovered in the 1890s?
In 1890s viruses were discovered because they can be filtered. Virus filtration
uses a membrane barrier to retain virus particles. It is a size-based removal
method which uses a specifically designed polymeric membrane to retain
virus particles on the surface and within the pores of the membrane.
Filterable infectious agents which depend on host organism for replication.
Extracts of an infected tobacco plant diluted into sterile medium produced
no additional infectious agents. Bacteria readily grew in the sterile media.
- First needed to be inoculated into leaves of healthy plants which then
developed TM disease.
- Serial transmission by diluted extracts- established the disease was not
due to bacterial toxin.
- Distinguished the reproductive and physical properties of the TM and
FMD agents.
If viruses are so small, how can we see them and why would we want to?
We can see them through electron microscope. We can only look at the virus
and study it. Without knowing its structure we can't develop vaccine and also
know how it infects and causes disease. It also help to distinguish between
two different types of viruses in order to treat it accurately.
If we consider viruses 'take over the cell factory' in order to replicate,
where do the virus instructions to the cell come from?
The virus hijack the cell and insert its DNA either into the cell genome or the
RNA is reverse transcripted into cDNA, this copy then integrates into the
cellular genome. But not all viral genome integrate into cellular genome. The
instructions come from the genetic codes of the virus itself.
Is a virus alive?
Viruses can't metabolise by themselves as they're inert and they can't
reproduce by themselves. But they can survive, stay intact and still have the
capacity to infect one even when they're not in a host.
Intro Page 1
25 December 2020 19:27
Introduction
Why study Viruses?
One main motivation for the study of viruses is the fact that they cause many
important infectious diseases, among them the common cold, influenza,
rabies, measles etc.
Once we understand their structure and how they cause disease we can then
design drugs to target viral infections. Viruses can be used for gene therapy,
vaccines and diagnosis.
➢ New viruses arise at any time
➢ Prevent and cure infection (vaccines, drugs)
➢ Control biological pests
➢ Treatment for cancers
➢ Help understanding of cells
How might you discover a virus?
Immuno-fluorescent assay
Antibody testing
Electron microscopy
How might virus have been discovered in the 1890s?
In 1890s viruses were discovered because they can be filtered. Virus filtration
uses a membrane barrier to retain virus particles. It is a size-based removal
method which uses a specifically designed polymeric membrane to retain
virus particles on the surface and within the pores of the membrane.
Filterable infectious agents which depend on host organism for replication.
Extracts of an infected tobacco plant diluted into sterile medium produced
no additional infectious agents. Bacteria readily grew in the sterile media.
- First needed to be inoculated into leaves of healthy plants which then
developed TM disease.
- Serial transmission by diluted extracts- established the disease was not
due to bacterial toxin.
- Distinguished the reproductive and physical properties of the TM and
FMD agents.
If viruses are so small, how can we see them and why would we want to?
We can see them through electron microscope. We can only look at the virus
and study it. Without knowing its structure we can't develop vaccine and also
know how it infects and causes disease. It also help to distinguish between
two different types of viruses in order to treat it accurately.
If we consider viruses 'take over the cell factory' in order to replicate,
where do the virus instructions to the cell come from?
The virus hijack the cell and insert its DNA either into the cell genome or the
RNA is reverse transcripted into cDNA, this copy then integrates into the
cellular genome. But not all viral genome integrate into cellular genome. The
instructions come from the genetic codes of the virus itself.
Is a virus alive?
Viruses can't metabolise by themselves as they're inert and they can't
reproduce by themselves. But they can survive, stay intact and still have the
capacity to infect one even when they're not in a host.
Intro Page 1
