Anthrax is an infectious disease caused by the bacteria Bacillus anthracis, a bacterium capable of living in a number of different environments, both arid, humid, and differing in soil pH and temperature. The disease has a number of different variations, determined by how infection occurred, cutaneous, inhalation, gastrointestinal, or injection, the latter of which being relatively rare . Anthrax infection in humans is relatively rare, and is typically contracted from close interaction with, or consumption of, infected animals, be they wildlife or livestock. This bacterium occurs naturally in the soil, commonly in agricultural regions, especially in Central and South America, sub-saharan Africa, central and southwest Asia, southern and eastern Europe, and the Caribbean ¹⁾ .

In sub-saharan africa, anthrax outbreaks are most common in savannah environments, where grazing animals, which are required for the bacteria's propogation, are commonly found. These areas are the same that often find themselves commonly used for the purposes of animal husbandry, often resulting in epizootic outbreaks of varying degrees and scales. ²⁾

The clinical symptoms of anthrax vary between variations, these are detailed below.³⁾ Symptoms of anthrax infection depent primarily on the method by which infection occurred, be it via direct skin contact, inhalation of spores, ingestion of spores, or accidental injection of spores or live bacteria. Symptoms typically appear within six days of infection⁴⁾ , and if left untreated are often fatal, with lethality rates ranging from 25% to 80% depending on how infection occurred⁵⁾ .

The symptoms of cutaneous anthrax can include:

• Small, itchy, blisters or bumps.
• Swelling around sores.
• Painless, black, sore or ulcer that appears after the bumps and blisters.

Fig 1: Sore caused by cutaneous anthrax infection ⁶⁾ .

The symptoms of inhalation anthrax can often include:

• Fever and chills
• Chest discomfort
• Shortness of breath
• Confusion or dizziness
• Cough
• Nausea, vomiting, or stomach pains
• Headache
• Sweating
• Tiredness
• Body aches

The symptoms of gastrointestinal anthrax include:

• Fever and chills
• Swelling of neck or neck glands
• Sore throat
• Painful swallowing
• Hoarseness
• Nausea and vomiting, especially with blood
• Diarrhea and bloody diarrhea
• Headache
• Red face and eyes
• Stomach pain
• Fainting
• Swelling of abdomen

The symptoms of injection anthrax can include:

• Fever and chills
• A group of small blisters or itchy bumps around the injection site
• A painless skin sore with a black center
• Swelling around the sore
• Abscesses deep under the skin or in muscle where the injection occurred.

Anthrax infection can occur from a number of different vectors, most frequently through contact with infected animals or through the use of contaminated materials ⁷⁾ . Anthrax infection occurs when Bacillus anthracis spores enter an organism and become active, they can then reproduce and spread throguhout the organism, producing toxins and otherwise causing damage. The variation of anthrax is determined by the method by which these spores were introduced to the organism's body, in the case of cutaneous infection, the organism's skin comes into physical contact with the bodies of either living or deceased organisms which contain spores. Inhalation then, involves the inhalation of spores, while gastrointestinal anthrax corresponds to their consumption, lastly, injection anthrax occurs typically when injection based drugs, contaminated with anthrax, are consumed ⁸⁾ .

Anthrax is typically treated through the use of antibiotics, this includes all variations of anthrax. Additional to anthrax, a doctor will oftenchoose specific medication and delivery method specific to the patient and their medical history. Anthrax may also be treated with anti-toxins, much of the damage caused by anthrax is due to the various toxins the bacteria in their active state, so anti-toxins are a prudent treatment for an ongoing anthrax infection ⁹⁾ . If treatment begins shortly after infection, or before severe symptoms begin, prognosis of patients suffering from anthrax is usually favorable, however, inhalation and gastrointestinal anthrax often still result in fatality even with aggressive treatment¹⁰⁾ , with the former having a roughly 55% survival rate with treatment, and the latter a 60% survival rate when properly treated.

The anthrax life cycle as observed in locations such as the namib desert can be divided into multiple stages. Bacillus anthracis can be found in the soil, which can then be interspersed through a population of plants, where the bacteria lives non-malignantly and can even be beneficial to some plants. These plants are consumed by herbivores, incidentally consuming the bacterial spores leading to an anthrax infection. These animals then die, and their carcasses release nutrients into the soil, which can be accessed by certain species of grass and shrub, and the bacteria found within the organism can enter the soil once more, entering into a non-malignant relationship with the plant life once more ¹¹⁾ .

fig 2; simplified anthrax lifecycle¹²⁾ .