Livestock and Letters: All About Anthrax

If you’ve ever been paranoid of opening a mysterious letter which arrived in the mail, perhaps it is because you were worried about Bacillus anthracis—the bacterial cause of the disease we know as Anthrax.
Anthrax is perhaps most infamous for the 2001 attacks following 9/11, in which several letters containing military grade anthrax bacteria spores were mailed to both media offices and U.S. Senators. Responsible for the death of five people and injury of seventeen more, the disease far predates any thought of biological warfare.
Typically, the majority of human exposure comes from those working with dead animals and animal products (i.e. meat, hide, wool, hair…). For this reason, the most historically dangerous form of anthrax contracted via inhalation was aptly dubbed “Woolsorters’ Disease”. In the present day, almost no accidental exposures of this nature occur, as animals raised for their products are not at risk for exposure to anthrax.
The etymology of the word comes from the Greek word for coal, which is likely due to the characteristic coal-black, boil-like skin lesions that form after cutaneous exposure to the bacteria. In French, it is known as maladie du charbon, or carbon sickness, for similar reasons.
The Bacillus anthracis spreads solely through airborne spores, meaning it is not possible to “catch” anthrax from an infected individual. However, their clothing and body may still possess spores, which is why appropriate decontamination of affected areas is paramount in limiting the harm of an outbreak.
Even more dangerous in the spreading of spores is the corpse of a deceased, infected individual, as the body and fluids will still contain a high concentration of bacteria which can likely be exuded into the environment.
Infection can occur through inhalation, ingestion or cutaneous exposure. Cutaneous exposure is, of the three, the least deadly due to very apparent symptoms and readily available antibiotics, while inhalation is the most common route and results in the most deaths as symptoms sometimes appear too late for treatment to prevent death.
Once infected, the bacteria multiply rapidly and produce three specific proteins, which are the actual cause of death. These three proteins are called the lethal factor, edema factor and protective antigen. Individually, none of them are capable of causing death: it is their combination that proves fatal.
The protective antigen reacts with both factors to produce two different deadly toxins (appropriately named edema toxin and lethal toxin), which, in turn, cause tissue swelling (edema), tissue destruction and the eventual death of the exposed organism.
It is for this reason that antibiotics must be taken promptly after exposure to the bacteria; if administered too late, lethal levels of the toxins produced by the anthrax can still remain in the host eventually causing death, despite removal of the anthrax bacteria itself.
If left untreated, anthrax disease can cause death between a few days to a few weeks after initial exposure to spores.
Luckily for us, monsieur Louis Pasteur developed the first vaccine for treating anthrax in 1881. He publicly demonstrated his concept of vaccination by preparing two groups of livestock, one of which was injected with his vaccine, and exposing them both to a strain of anthrax bacteria. All members of the control group died, while all the vaccinated animals survived.