' 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.
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."
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.'