Anthrax historical perspective
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
Historical perspective
Ancient Origins of Anthrax
Anthrax is thought to have originated in Egypt and Mesopotamia. Many scholars think that in Moses’ time, during the 10 plagues of Egypt, anthrax may have caused what was known as the fifth plague, described as a sickness affecting horses, cattle, sheep, camels and oxen. Ancient Greece and Rome were also well acquainted with anthrax, and this is illustrated in many of the ancient writings of the most famous scholars from those times. For example, many scholars think anthrax was depicted by Homer in the Iliad from 1230 BC and by Virgil in 70-90 BC. Some even suggest that anthrax may have contributed to the fall of Rome. The first clinical descriptions of cutaneous anthrax were given by Maret in 1752 and Fournier in 1769. Before this, anthrax had only been described through historical accounts.
Koch Postulates
In 1877, scientist Robert Koch studied Bacillus anthracis, the bacterium that causes anthrax. He discovered that the bacteria formed spores that were able to survive for very long periods of time and in many different environments. Koch decided to use anthrax bacteria in one of his most important historical experiments, in which he isolated and grew Bacillus anthracis in pure culture and injected animals with the bacteria. Using what he observed in this study, he described how the microbe he injected into the animals caused the disease. From these studies, he was also able to determine the life cycle of the anthrax bacteria and was able to demonstrate what became known as Koch’s postulates, which demonstrate a causal relationship between a specific microorganism and a disease.
Wool Sorters Disease
During the 1800s, doctors saw cases of anthrax but did not yet have a diagnosis for the disease. During this time, the organism that causes anthrax had not yet been discovered, but doctors had noticed a link between the disease and the animal hair industry. Because of this, the disease became known as “wool sorters disease.” By the middle of the century, early researchers had associated the disease with the presence of rod-shaped bodies that were seen in the blood of infected animals. These bodies were eventually identified as bacteria and given the name Bacillus anthracis.
First Anthrax Vaccine
In 1881, Louis Pasteur, another prominent scientist, took Koch’s work a step further, trying to fully prove how anthrax was spread and how it made people or animals sick. Pasteur also worked to create a vaccine for anthrax. In his experiment, Pasteur gave 25 animals two shots of an anthrax vaccine he had created with weakened anthrax bacteria. After he gave both rounds of the vaccine to these animals, he injected them with live anthrax bacteria. He also injected live bacteria into 25 other animals that had not been vaccinated. Each of the vaccinated animals survived, while the 25 that were not vaccinated died.
Anthrax in the US
Much knowledge was gained about anthrax in the 1800s. As a result, animal and human cases of anthrax in the United States, Britain, and Germany were well documented in the early 1900s. However, there were still places where anthrax cases hadn’t been documented, such as Russia, Asia, India and Africa. Because of the high number of contaminated animal products imported from these countries, however, it was known that anthrax had to be widespread in these regions.
Animal Vaccination Reduces Human Cases
In 1937, Max Sterne successfully created the anthrax live spore vaccine for animals. This vaccine is still used in animals in most countries. Because of the introduction of routine vaccination of animals against anthrax and the improvements in animal product processing procedures, the number of cases of anthrax in humans declined. This decline was so significant that during the entire 20th century there were only 18 cases of inhalation anthrax in the United States.
Penicillin for Anthrax
Penicillin had been discovered in 1928, but it wasn’t until 1944 when it was first used to treat anthrax. Penicillin became the drug of choice for treating anthrax, and it replaced all previous therapies, such as serum therapies and chemotherapies.
First Human Anthrax Vaccine
In 1950, the first anthrax vaccine for humans was created. This anthrax vaccine was tested in a group of goat hair mill workers. Volunteers were given either the vaccine or a placebo (a shot that does not have the vaccine in it). The volunteers were then followed over a 2-year period. This study determined that the vaccine was 92.5% effective in preventing cutaneous anthrax. After the study, the vaccine was made available to people working in goat hair processing mills in the United States.