炭疽杆菌:Thebacteriumthat causes anthrax. Anthrax differs from mostbacteriainthat they exist in an inactive (dormant) state called spores. The spores are found in soil, animal carcasses andfeces(including sheep, goats, cattle, bison, horses, and deer), and animal products (e.g., hides and wool). Some animals (cats,dogs, rats, and swine) are very resistant to anthrax. Remarkably, anthrax spores can remain dormant in soil for many years, perhaps decades. Likened somewhat to eggs that have the ability to hatch, spores can transform (germinate) into active bacteria under appropriate conditions.
The spores themselves do not cause significant damage totissue. Once in the body, the spores germinate to form thevirulent(disease-causing) bacteria. Thus, the spores can lead to disease by:
- entering brokenskinand germinating there to causecutaneousanthrax;
- being inhaled and germinating in thelungsto cause inhalation anthrax; or
- 被吃掉and germinating in thegastrointestinal tractto causegastrointestinalanthrax.
炭疽杆菌was discovered in 1850. Notably, it was actually the first bacterium to be shown to cause a disease. In fact, it was the great Germanphysician, Robert Koch, who discovered this. He grew the anthrax bacteria incultureplates, injected them into animals, and thereby demonstrated that the bacteria produced the disease.
Then, the famous French scientist, Louis Pasteur (known for pasteurizing milk), used anthrax bacteria that he damaged to develop a vaccine for anthrax.Hisidea was that the damaged bacteria would not cause the disease, but would still protect (produceimmunity) against anthrax. Indeed, he showed that this vaccine protected animals from getting the disease when they were subsequently injected withhealthy, virulent (disease-causing) anthrax bacteria.
