Bacillus anthracis is the causative organism of the serious infectious disease, called anthrax. There are three manifestations of this disease. The manifestations include gastrointestinal anthrax, inhalation anthrax, and cutaneous anthrax. This research will explore the morphology, virulence factors, reservoir, transmission, and portal of entry of B. anthracis. The pathogenesis will also be reviewed, including symptoms, how B. anthracis causes these symptoms, the possible complications of the symptoms, role of virulence factors, and the evasion of the hosts’ defense mechanisms. Morbidity and mortality rates, diagnosis, treatment, prevention including the use of vaccines, and why it is socially relevant to continue research on B. anthracis is also included in this review. Bacillus anthracis’ morphological details include the microorganism being a gram-positive, bacilli shaped, or rod-shaped, spore-forming bacteria [1]. The virulence factors of an organism allow it to prevail within the environment and host, and also enable colonization within the host. B. anthracis has 3 main virulence factors coded on 2 plasmids, which are pXO1 and pXO2. If one of these two plasmids is missing or mutated, the organism cannot produce all of its virulence factors. The resulting organism is weakened, which means its virulence and the ability to cause illness in animals and people have now been reduced [2]. B. anthracis produces two toxins, called edema toxin and lethal toxin. The plasmid that controls the production of the edema and lethal toxins in anthrax is pXO1. The edema and lethal toxins are made of three proteins, the edema factor, the protective antigen, and the lethal factor. The plasmid that codes for the capsule, which is a layer of polysaccharides outside of the cell wall, is pXO2. This capsule protects the bacteria against phagocytosis, or consumption by defensive cells from the immune system. Without its capsule, the bacteria can be phagocytised, thus being destroyed [3]. B.
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anthracis is an endospore-forming, facultatively anaerobic, bacterium that normally dwells in soil, vegetation and mainly livestock that are herbivores (Micro book). Although B. anthracis causes one disease, there is three manifestations or transmission of this bacterium. The three manifestations include gastrointestinal anthrax, inhalation anthrax, and cutaneous anthrax. B. anthracis is a zoonotic bacterium, meaning it is spread between animals and the environment to humans. (cite).
For each manifestation, there is a different mode of transmission. Gastrointestinal anthrax is contracted when eating undercooked or raw meat of an infected animal, such as eating meat from an infected cow. Infection occurs when spores attach to the mucosal surfaces of the gastrointestinal tract. However, gastrointestinal anthrax is rare in the United States due to livestock being routinely vaccinated for anthrax [4].
Inhalation anthrax is often used as a bioterrorism attack mechanism. Its portal of entry occurs when the spores of B. anthracis are inhaled from the dust particles in the air [5]. The bacterial particles inhaled are usually from the exposure to the air around infected animals or contaminated products. The contaminated products that can become aerosolized are meat, hides, or hair. Once the spores are inhaled germination occurs. After germination in the macrophages, the macrophages will transport the spores to the mediastinal and tracheobronchial lymph nodes [6]. Cutaneous anthrax is the third mechanism that is most common in humans, accounting for about 95% of B. anthracis infections. The bacterium’s portal of entry for cutaneous anthrax is a cut or an abrasion on the skin. The organism can enter the host through the cut on the skin when the skin becomes in contact with infected animals or infected animal products. Cutaneous anthrax can also become contracted when coming into contact with contaminated soil or vegetation [7]. Each manifestation caused by B. anthracis involves its own list of symptoms, whether they are mild or extreme. Gastrointestinal anthrax symptoms include: anorexia from lack of appetite, nausea, vomiting of blood, and abdominal pain. There may be bloody diarrhea and ascites, both of which may be hemorrhagic [8]. These symptoms occur when the spores are swallowed/eaten, causing gastrointestinal anthrax, the spore can cause lesions in the oral cavity and throughout into the cecum. These ulcerative lesions can occur in the esophagus and stomach as well. These lesions may bleed causing hemorrhaging or perforations causing the abdominal pain, bloody stool, and blood in vomit. The lesions that lead to hemorrhaging or perforations
anthracis is an endospore-forming, facultatively anaerobic, bacterium that normally dwells in soil, vegetation and mainly livestock that are herbivores (Micro book). Although B. anthracis causes one disease, there is three manifestations or transmission of this bacterium. The three manifestations include gastrointestinal anthrax, inhalation anthrax, and cutaneous anthrax. B. anthracis is a zoonotic bacterium, meaning it is spread between animals and the environment to humans. (cite).
For each manifestation, there is a different mode of transmission. Gastrointestinal anthrax is contracted when eating undercooked or raw meat of an infected animal, such as eating meat from an infected cow. Infection occurs when spores attach to the mucosal surfaces of the gastrointestinal tract. However, gastrointestinal anthrax is rare in the United States due to livestock being routinely vaccinated for anthrax [4].
Inhalation anthrax is often used as a bioterrorism attack mechanism. Its portal of entry occurs when the spores of B. anthracis are inhaled from the dust particles in the air [5]. The bacterial particles inhaled are usually from the exposure to the air around infected animals or contaminated products. The contaminated products that can become aerosolized are meat, hides, or hair. Once the spores are inhaled germination occurs. After germination in the macrophages, the macrophages will transport the spores to the mediastinal and tracheobronchial lymph nodes [6]. Cutaneous anthrax is the third mechanism that is most common in humans, accounting for about 95% of B. anthracis infections. The bacterium’s portal of entry for cutaneous anthrax is a cut or an abrasion on the skin. The organism can enter the host through the cut on the skin when the skin becomes in contact with infected animals or infected animal products. Cutaneous anthrax can also become contracted when coming into contact with contaminated soil or vegetation [7]. Each manifestation caused by B. anthracis involves its own list of symptoms, whether they are mild or extreme. Gastrointestinal anthrax symptoms include: anorexia from lack of appetite, nausea, vomiting of blood, and abdominal pain. There may be bloody diarrhea and ascites, both of which may be hemorrhagic [8]. These symptoms occur when the spores are swallowed/eaten, causing gastrointestinal anthrax, the spore can cause lesions in the oral cavity and throughout into the cecum. These ulcerative lesions can occur in the esophagus and stomach as well. These lesions may bleed causing hemorrhaging or perforations causing the abdominal pain, bloody stool, and blood in vomit. The lesions that lead to hemorrhaging or perforations