A virus is not a
cell, it’s more like a molecule, and shows behaviour
like the molecule in the sense that viruses can crystallize. The shape of
viruses also varies. Some look like pencils, some look
like spiked golf balls.
Composition of
T-Even Bacteriophage
The Capsid
- The Capsid of a virus is basically its "brains." It contains an outer
protein coat which is wrapped around a central core of a highly complex
chemical called nucleic acid. Typically, the capsid is divided into
distinct subunits called capsomeres. X-rays have shown that viruses
have an icosahendron capsid (30 sides).
The Body
- Viruses have a highly complex symmetry, somewhat like the Surveyor
space craft send to explore the moon. Attached to the head (capsid) is
a rod like structure that consists of a retractible sheath surrounding
a central hollow core.
The Tails
- At the very end of the core is a spiked plate carrying 6 slender tail
fibers which help anchor the virus to its host.
Here is a
schematic drawing (source: thinkquest.org) of a type of virus
which is called a “bacteriophage”. Bacteriophages – or just phages -
are typically large viruses, which attack bacteria. The phages were
first discovered around 1916. They have been much used in the study of
bacterial genetics and cellular control mechanisms largely because the
bacterial hosts are so easily grown and infected with phage in the
laboratory.
Phages were also
used in an attempt to destroy bacteria that cause
epidemic diseases, but this approach was largely abandoned in the 1940s
when antibacterial drugs became available. The possibility of “phage
therapy” has recently attracted new interest among medical researchers,
however, owing to the increasing threat posed by drug-resistant
bacteria. (source: the Columbia encyclopaedia, 2001)
Viral infection,
what really happens?
Most viruses are
harmless, and do not cause
diseases. But there are viruses that can cause paralysis (polio virus)
and even cancer. There are viruses that make you sick by releasing
toxics that are the result of their cellular invasion, and others make
you sick, because they destroy cells that function to keep your body
from getting sick.
Let’s see what
happens when you catch a cold.
An infected
person sneezes near you.
You inhale the
virus particle, and it attaches
to cells lining the sinuses in your nose.
The virus attacks
the cells lining the sinuses
and rapidly reproduces new viruses.
The host cells
break, and new viruses spread
into your bloodstream and
also into your lungs. Because you have lost cells lining your sinuses,
fluid can flow into your nasal passages and give you a runny nose.
Viruses in the
fluid that drips down your
throat attack the cells lining your throat and give you a sore throat.
Viruses in
your bloodstream can attack muscle
cells and cause you to have muscle aches.
picture
2 T-Even virus, attacking a cell
Now how
can
we get rid of a virus?
Your immune
system detects the virus
and starts producing a chemical called “pyrogens”. This chemical will
raise your body temperature, causing a fever. Because most viruses only
become active (start their reproductive cycle) within a certain narrow
temperature range, a fever will slow down, or even halt the virus from
attacking new host cells. The virus will die down, and you’ll get
better.
Antibiotics only
have a limited use in the fight against viruses. They
won’t kill the virus, but they will kill bacteria that – as a result
from the viral attack – saw the road cleared to an attack. Sometimes
viruses cause inflammatory reactions because the body reacts to the
cells that are altered by the virus. In that case medication against
inflammatory reactions work to help you feel better. Injections with a
small quantity of the virus will cause the immune
system to develop antibodies that will attack the virus before it gets
a chance to start its destructive reproductive cycle. Immunisation is a
powerful tool against viruses, and some viruses even nearly disappeared
from the face of the earth trough immunisation, but because the virus
can alter its genetics, the possibility that it stays ahead of
immunisation is always lurking.
Why is HIV
different?
The HIV virus
attacks T-cells in the immune
system, eventually causing AIDS (acquired immunodeficiency syndrome).
There is no such thing as an AIDS virus. HIV progressively destroys the
body's ability to fight infections and certain cancers. People
diagnosed with AIDS may get life-threatening diseases called
opportunistic infections, which are caused by microbes such as viruses
or bacteria that usually do not make healthy people sick. In other
words: HIV is different, because it directly attacks the body’s ability
to regain health.
picture
3 Schematic picture of HIV
Can man
made viruses wipe out the world’s population?
Yes, in
theory they can. Scientists have
claimed producing new
bacteriophages – viruses that attack bacteria for environmental
purposes. Of course we should not kid each other. When something can be
used as a weapon, some government will jump up and develop it as a
weapon. Already groups of people are discussing the possibility of HIV
and Ebola being man made in some military laboratory. Only time will
tell if this is true and if we are facing doom from viral weapons.
Meanwhile we are facing the threat of natural
viruses altering their
own genetics in an increasingly rapid pace. There is a distinct
possibility the Spanish flu
disaster of 1918,
when millions of people
died from a simple influenza,
will be repeated in the near future.
Some
scientists fear that the number of deaths resulting from this new super
virus will be many times higher. It could well prove to be a virus for
which no immunisation will be possible to develop.
It’s really mind
baffling that a living dead particle might prove to be
the end of us all. Will the zombies get us after all?!?
Hans de Vries
(dutchie) for Armageddon Online November 2004 Armageddon
Online