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THE
INS
AND
OUTS
OF
VIROLOGY
Viruses are so tiny that they can only be seen through the electronic
microscope.75o/o
of
all
human
infections are
due
to them. Spread is
rapid and
wide.
Even
diseases thought to be unrelated
to
infections
have now been identified to previous infections
by
viruses. From
1994,
30+ kinds of new types
of
viruses are
discovered. Although
the
definitive clinical diagnosis of
viral
infections is not easy, specific
immunization
by
vaccines are etfective. Both
the
SARS
in
2003 and the Avian
flu
in 2004 shocked mankind. Moreover, more
prevalent international travels increase possibility
of
future
large
epidemics. Viruses
must
go
into
the
host
cells to make use
of
the
host cells' biological systems before they can copy themselves repeatedly,
in
just
10
hours or
so.
After that,
the
host
cells start to
die.
Rarely,
the
host cells may become cancerous. Most viruses
are cold resistant but heating to 56o
C
for 30 min.
or
100
o
C
for seconds would
kill
them. X-rays, ultra-violet
rays, hydrogen peroxide, alcohol, etc., are also effective. Viruses often mutate and 2 viruses may also com-
bine together. lmmunity to viruses
is
through interferons and specific antibodies generated
-
both can
be
transferred
to
others
for
prevention purposes. Some immunity, e.9., those through vaccination
for
polio and
small pox, would usually last
a
lifetime. Testing serum anti-viral immuno-globulins against
viral
antigens
enables convenient
diagnosis
but
treatment
is
still
unsatisfactory.
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