Anthrax Used by Koch and Pasteur to Prove Germ Theory of Disease in 19th C.
Washington Times 14oct01
PALM BEACH, FL — Anthrax is not only one of the oldest diseases, but its causative agent was the first one in history to be definitively isolated, reproduced and linked to the disease that affects both livestock and humans.
Robert Koch & Louis Pasteur
Two 19th-century scientists, Robert Koch (1843-1910), a German, and France's Louis Pasteur (1822-1895), used anthrax to prove the germ theory of disease — that is, the belief that micro-organisms caused maladies.
To be sure, they were not the first to suggest a germ theory. As far back as 1721 in Boston, the Rev. Cotton Mather inoculated 240 persons with smallpox fluid to successfully ward off the disease for virtually all the recipients. Nor were Koch and Pasteur alone in dealing with the anthrax bacteria.
Other scientists before them had detected rod-shaped organisms in the bodies of animals dying from anthrax, as well as in soil and water samples from farms. But in 1876, Koch recovered these organisms, cultivated them in a pure culture and then used these cultures in healthy animals to prove that the bacillus anthracis was the infecting agent. Five years later, Pasteur relied on Koch's work to develop an anthrax vaccine.
Koch earned his medical degree in 1866, and six years later became the medical director for Wollstein, Germany, a farm area where livestock were devastated by fatalities from anthrax. Although Koch's main responsibility was to care for humans and not farm animals, he conducted anthrax experiments in his small, four-room apartment, using a microscope his wife had given to him and the remains of livestock that had died from the disease.
Koch removed the spleens of infected animals, taking the blood from the organs and injecting it, using slivers of wood, into healthy mice, which came down with the disease. Despite proving cause-and-effect, Koch wanted to know more, because when the blood of an infected animal was several days old, or even dry, it lacked the ability to transmit the disease, although the organism continued to live in soil and water.
"How is it possible, then," Koch wrote, "for an organism which is so easily destroyed to maintain itself as a dormant contagion in soil?" So Koch extracted an eye from a cow that had just died, taking the aqueous humor (the fluid surrounding the cornea) and placing it on microscope slides with anthrax bacilli from a cow that had just died from anthrax. The resulting cultures were then covered with a protective glass.
Koch observed and even photographed the results over a long time, noting that under favorable conditions (moisture, with ample oxygen), the bacilli thrived as active germs. Under unfavorable conditions (dry, with little oxygen), they produced spores that could live indefinitely and return to active bacilli when optimal conditions returned.
Most importantly, the research illustrated that contact with animals or humans was not a precondition for the bacilli to live.
Pasteur would draw upon these artificially grown cultures to develop not only a vaccine for anthrax in 1881, but also to use the same methods to devise a rabies vaccine three years later.
Koch would move to the same type of pioneering work in cholera, tuberculosis and other diseases, eventually winning a Nobel Prize in medicine in 1905.
For much of the world's history, both before and after the work of Koch and Pasteur, the focus of anthrax prevention was on animals, not humans, because the most likely form of the disease in humans was caused by butchers' handling the meat of infected animals or from the use of animal hides, hair, fur, or wool (hence the term "wool-sorter's disease"). Even barbers and their clients were sometimes affected, as a result of using infected horse-hair shaving brushes.
But in the entire 20th century, anthrax in developed countries had been a rarity, with only 18 cases of inhaled anthrax, from spores, recorded until the recent cases.
Introduction to Virology - Notes taken from Chapter 1 of Principles of Molecular Virology
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