Anthrax
Bacillus anthracis
''Bacillus anthracis'' is a Gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent pathogen within the genus ''Bacillus''. Its infection is a type of zoonosis, as it is transmitted from animals to humans. It was discovered by a German physician Robert Koch in 1876, and became the first bacterium to be experimentally shown as a pathogen. The discovery was also the first scientific evidence for the germ theory of diseases.
''B. anthracis'' measures about 3 to 5 μm long and 1 to 1.2 μm wide, and has a genome of 5,227,293 bp in a single circular DNA. It has two extrachromosal DNA plasmids, pXO1 and pXO2, which are responsible for the pathogenicity. It forms a protective layer called endospore by which it can remain inactive for many years and suddenly becomes infective under suitable environmental conditions. Because of the resilience of the endospore, the bacterium is one of the most popular biological weapons. The protein capsule is key to evasion of the immune response. It feeds on the heme of blood protein haemoglobin using two secretory siderophore proteins, IsdX1 and IsdX2.
Untreated ''B. anthracis'' infection is usually deadly. Infection is indicated by inflammatory, black, necrotic lesion . The sores usually appear on the face, neck, arms, or hands. The fatal symptoms include flu-like fever, chest discomfort, diaphoresis, and body aches. The first animal vaccine against anthrax was developed by French chemist Louis Pasteur in 1881. Different animal and human vaccines are now available. The infection can be treated with common antibiotics such as penicillins, quinolones, and tetracyclines.
''B. anthracis'' measures about 3 to 5 μm long and 1 to 1.2 μm wide, and has a genome of 5,227,293 bp in a single circular DNA. It has two extrachromosal DNA plasmids, pXO1 and pXO2, which are responsible for the pathogenicity. It forms a protective layer called endospore by which it can remain inactive for many years and suddenly becomes infective under suitable environmental conditions. Because of the resilience of the endospore, the bacterium is one of the most popular biological weapons. The protein capsule is key to evasion of the immune response. It feeds on the heme of blood protein haemoglobin using two secretory siderophore proteins, IsdX1 and IsdX2.
Untreated ''B. anthracis'' infection is usually deadly. Infection is indicated by inflammatory, black, necrotic lesion . The sores usually appear on the face, neck, arms, or hands. The fatal symptoms include flu-like fever, chest discomfort, diaphoresis, and body aches. The first animal vaccine against anthrax was developed by French chemist Louis Pasteur in 1881. Different animal and human vaccines are now available. The infection can be treated with common antibiotics such as penicillins, quinolones, and tetracyclines.