Anthrax


Name of disease:
Anthrax: an infectious disease caused by the ingestion of Bacillus Anthracis endospores. [1]

Root cause of disease:
Human ingestion of the spores of the bacterium Bacillus Anthracis via transmission through a cut or abrasion on the skin (Cutaneous Anthrax), ingestion of infected meat (Gastrointestinal Anthrax) or inhalation of the spores (Inhalation or Pulmonary Anrthrax). [1]

Affected cell types/tissues/organ/systems:
Anthrax can affect human or animal species. Spores of the bacterium are entered into the body through the three routes (ingestion, inhalation, or from a cut) and germination or regrowth of the bacteria is induced. Symptoms develop according to route of entry. Once the spores become metabolically active again and start to grow as active B.anthracis they multiple and burst white blood cells, releasing numerous bacteria into blood stream, which results in infection throughout the body [2]. Once this bacteria is in the blood stream it releases three proteins to the cells of the body , the Lethal Factor (LF), the Edema Factor (EF), and the Protective Agent (PA), where the lethal factor and the edema factor each bind with the protective agent to make harmful toxins which are the lethal toxin, and the edema toxin, respectively [3]. These toxins cause tissue destruction, cell death, bleeding, and death in the host or person infected with Anthrax [3].


Historical background:
Historically, Anthrax has been prevalently seen throughout the world for centuries and has been known for a long period of time. The study of Anthrax helped scientist make historical marks in the study of medicine, diseases, and microbiology. Anthrax was the first disease that a bacterium, which was the Bacillus Anthracis bacterium, was known as an etiological agent of the disease [4]. This discovery was the first that revealed a disease could be causes by a microbe. This discovery was made by well known microbiologist Robert Koch. Koch discovered the usage of the spore of the bacterium the spore aids in infecting the host. Koch’s work with Anthrax also helped bring about “Koch’s Postulates”, which is a set of guidelines still used today to determine cause and effect of an infectious disease and laboratory ways to research it [4]. The anthrax vaccine was also a groundbreaking mark in medicinal history by being the first vaccination created. This vaccine was invented by Louis Pasteur in 1881 [4]. One major historical event associate with this disease is the idea of Anthrax being utilized as a biological weapon of warfare. The usage of this disease as a biological weapon has been demonstrated as early as 1916 to the most current anthrax attacks of 2001 [4] [3].

endspore.jpg

Figure one: visualizes the bacillus anthracis bacterial cell and the endospore of the bacteria.



Common symptoms:
Common symptoms vary throughout the various three forms of the disease.
Symptoms of the Cutaneous form of Anthrax include a raised, itchy bump that resembles an insect bite located at the cut or abrasion where the spores enter. The bump then develops into a blister. This blister then turns into a painless ulcer with a black necrotic area in the center [1]. These symptoms are visualized in the figure below.

Stages of cutaneous anthrax.jpg


Figure two : visualizes the different stages of the bacterial infection.

Symptoms of Gastrointestinal Anthrax are vomiting, diarrhea, loss of appetite, lesions on intestines, mouth, and skin [1].
gi-anthrax.gif
Figure three: Shows bacterial pathway through the body from the start of ingestion of B.Anthracis spores



Symptoms of Inhalation Anthrax include cold or flu like symptoms followed by pneumonia and severe respiratory collapse [1].

inhaled-anthrax.gif


Figure four: Shows the bacterial pathway once a human inhales the bacterial spores

Standard treatments:
Standard treatments of Anthrax included the usage of Antibiotics such as ciprofloxacin, doxycycline, or penicillin to fight infection [1]. The amount and type of antibiotic is determined based on the form of anthrax/severity Anthrax that is seen in the patient. Even with treatment, Anthrax is very fatal disease with its most fatal form being Inhalation Anthrax representing over a 75% mortality rate even with treatment [1]. There is also an anthrax vaccine but is only giving to patients with a very high risk of contracting the disease.


Current research:
Current Research is primarily involved with the further investigation of the spores and the toxins of Bacillus Anthracis. This can lead to advancements in treatments, vaccines, and also new clean up and decontamination techniques of infected areas [2][4].

Life Cycle of Anthrax
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References:
[1] Center for Disease Control and Prevention (2013). Anthrax. Retrievied from: http://www.cdc.gov/anthrax/basics/
[2] Driks, A. (2009). The bacillus anthracis spore. Molecular Aspects of Medicine, 30(6), 368-373.
[3] Scobie, H. M., & Young, J. A. (2005). Interactions between anthrax toxin receptors and protective antigen. Current Opinion in Microbiology, 8, 106-112.
[4]Schwartz, M. (2009). Dr. jekyll and mr. hyde: A short history of anthrax. Molecular Aspects of Medicine, 30(6), 347-355.

By: Gina Ghianni