'
From: 'Rats, Lice and History' (1935)
by flans Zinsser (American bacteriologist). This booklet regularly
deals with viruses but what really is a virus? And how does a virus
differ from a bacterium? The 'world of microbes' under the looking
glass.
Micro-organisms
Living organisms, too small to detect with the
naked eye, were first discovered by the Dutch
scientist, Antoni van Leeuwenhoek (163 2-172
3). Van Leeuwenhoek dedicated much of his
time to the grinding of magnifying lenses. He
produced the best lenses available at that time,
with a magnification of approximately 300
times. Van Leeuwenhoek's amazement while observing the world of
microbes could nicely be made out from one of
his letters to the Royal Society regarding a
rotten tooth: "I removed this stuff from the
root cavities, mixed it with clear water and
placed it under a microscope... I have to admit
that the stuff looks like it is living. But even so,
the volume of those tiny creatures was so
extraordinarily large, that around a billion would
be needed to make up a grain of sand."
Viruses
A virus is a piece of DNA and is much smaller
than the smallest known bacterium. Viruses
cannot multiply by themselves and do not stay
alive outside of the host body. The most
important weapon of man against viruses is the
immune system. This system functions in two
ways: It helps us to recover from a virus disease
and protects us from a following infection.
Some viruses, like HIV, destroy their host's
immune system. Others have learned to 'hide' in
cells, specially selected for this purpose and
sporadically appear at 'convenient' moments.
Herpes Simplex, for example - this virus lives in
the nervous system of as many
as 90% of all adults. If your resistance gets weaker or you
had too much sun, this virus causes cold sores on the lips.
The third virus category has developed a mechanism
which treats every contact with the immune system as a
new encounter, like the flu virus for example.
The virus as secret weapon
In the history of mankind, virus
diseases are important events.
It is highly unlikely that in 1520, a small
group of Spanish soldiers could have
defeated the Indians in Mexico without
the smallpox epidemic, which the
soldiers unknowingly carried with
them into the New World
Penicillin discovered by accident
After a vacation in 1928, the Scottish scientist Alexander Fleming (1888-1955) returned to his London laboratory , On
his worktop, he noticed that the lid of a culture dish with staphylococci had come loose, which resulted in the
contamination of the culture with its yeast and fungi.
Fleming found that all staphylococci on the spot where Penicillum notaturn (one of the fungi) had developed, were
dead. Upon further investigation by way of elimination, he succeeded in reducing
this occurrence to the presence of an active substance in the fungus.
In 1929, he gave this substance the name 'penicillin', derived from the name of the fungus.
In 1940, the researchers Howard Florey and E. B. Chain succeeded in isolating penicillin and confirming its bacteria
killing ability: As cure for several infectious diseases, including syphilis, the
magical fungus turned out to be one of the most important discoveries in modern medicine, which - and this is
most astounding - was purely due to coincidence. Fleming: 'There are thousands of different fungi and a thousand
types of bacteria, so that the chance to
combine these two at the right moment,
was just as small as winning themain prize in a lottery.'