Anthrax
The deadly outbreaks of anthrax in the nineteenth century baffled farmers who were raising their cattle in fields that had been cleared of any infected animals. They did not understand the cause of the recurring outbreaks which killed farm animals as well as their handlers.
In humans, anthrax may manifest itself as malignant pustules (the cutaneous form of the disease), which could be contracted from the bristles of a shaving brush containing the spores, or from exposure to hides or blood of infected animals. Anthrax pneumonia (inhalation anthrax), or "wool sorter's disease," was prevalent among those working with hides and wool. An intestinal form of the disease resulted from eating anthrax-contaminated meat.
Rod-shaped organisms, Bacillus anthracis, were discovered in the blood of anthrax-infected animals as early as 1850 by French physician Casimir Joseph Davaine (1812-1882), who postulated that these organisms cause the disease. In 1876 Robert Koch, demonstrated that these rod-shaped bodies were present in the blood of infected animals, and absent from healthy ones, thus confirming Davaine's hypothesis.
During additional experimentation, Koch determined the life cycle of the bacillus. In presenting his findings, he demonstrated that the bacilli formed spores that were resistant to outside influences, including heat, and could remain for long periods in a state of suspended animation waiting to infect and kill the next victims. Therefore, under proper external conditions, the spores in the blood and tissues of dead animals could become virulent and set off a recurrence of the deadly disease. This explained new outbreaks of anthrax in fields that had been cleared of infected animals. Louis Pasteur conducted his first experiments on anthrax with physicist Jules Joubert in 1877. They confirmed Koch's earlier experiments to show that dilution of Bacillus anthracis did not alter the virulence of the bacillus. He also discovered that earthworms, passing over the bodies of animals that had died of anthrax, were carrying the spores to the grass above and infecting healthy animals. Therefore, a vaccine was imperative for saving cattle, sheep, and horses from the reviving spores. Pasteur turned his attention to finding a vaccine for anthrax.
Pasteur, and his medical and veterinary colleagues Pierre-Paul-Emile Roux (1853-1933) and Charles-Edouard Chamberland (1851-1908), discovered that bacilli kept at 108-109°F (42-43°C) were reduced in virulence and lost their ability to make spores. This left the organism in an attenuated, or weakened, form. On May 5, 1881, the trio of Pasteur, Roux, and Chamberland answered a challenge by the Agricultural Society of Melun to give a public demonstration of their work. They inoculated 24 sheep, one goat, and six cows with a living attenuated vaccine, and on May 17 with a less attenuated culture. Another 24 sheep, one goat and four cows were not inoculated. On May 31, the animals were exposed to anthrax bacilli. Within two days, the uninoculated sheep and goat were dead; the four cows were sick. The inoculated animals were healthy and grazing in the fields.
In 1935 Mario Mazzucchi of Milan produced a vaccine by suspending anthrax spores in saponin. He claimed that his vaccine, unlike Pasteur's, was stable in virulence and protection. Four years later, Max Sterne in South Africa formulated a vaccine of avirulent uncapsulated sporing bacilli. It was reported to be even safer and to produce fewer side effects.
The first vaccine for humans was developed in 1948 by G.P. Gladstone of Oxford University. It is an alum precipitate of the antigen found in sterile filtrates of the bacillus, and it is used primarily to safeguard humans working with imported animal hairs, wools, hides and bone meal.
Anthrax was also used in biological warfare during World War II, and may still be a threat as a weapon today. In 1979 an unusually severe outbreak of the inhalation form of anthrax resulted in over 1,000 fatalities around the Russian city of Sverdlovsk. Although information remains sketchy, it is thought that this outbreak may have resulted from an accident at a biological warfare facility.
In December of 1997, the Pentagon announced a plan to innoculate United States troops against anthrax as a precaution against biological warfare attacks, particularly from the Middle East and Asia.Fears that the civilian population of the United States and other countries may be targeted as well, has led to the formation and training of Hazardous Materials Teams, Hazmats, to contain such an outbreak. Worries that smallpox or other diseases may be used as biological weapons has increased concerns on this issue.
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