|
|
| (18 intermediate revisions by 3 users not shown) |
| Line 1: |
Line 1: |
| __NOTOC__
| | #REDIRECT [[Bacillus anthracis]] |
| {{Anthrax}}
| |
| {{CMG}}; {{AE}} {{JS}}
| |
| ==Overview==
| |
| The causative agent of anthrax is [[B. anthracis]], a nonmotile, [[Gram-positive]], [[aerobic]] or facultatively anaerobic, [[endospore]]-forming, [[rod]]-shaped [[bacterium]]. The [[spores]] of [[B. anthracis]], which can remain dormant in the environment for decades, are the [[infectious]] form, but vegetative [[B. anthracis]] rarely causes disease.<ref>{{Cite journal | author = [[Sean V. Shadomy]] & [[Theresa L. Smith]] | title = Zoonosis update. Anthrax | journal = [[Journal of the American Veterinary Medical Association]] | volume = 233 | issue = 1 | pages = 63–72 | year = 2008 | month = July | doi = 10.2460/javma.233.1.63 | pmid = 18593313}}</ref> The [[natural reservoir]]s of [[Bacillus anthracis]] includes humans, mammals, herbivores, reptiles, and birds.
| |
| | |
| ==Taxonomy==
| |
| [[Bacterium|Bacteria]]; [[Archaebacteria]]; [[Firmicutes]]; [[Bacilli]]; [[Bacillales]]; [[Bacillaceae]]; [[Bacillus]]; anthracis; Bacillus anthracis
| |
| | |
| ==Biology==
| |
| {| style="float: right;"
| |
| | [[File:AnthraxCauses2.png|200px|thumb|none| Photomicrograph depicting a number of Gram-positive, endospore-forming Bacillus anthracis bacteria<SMALL>Courtesy: ''[http://phil.cdc.gov/phil/home.asp Public Health Image Library (PHIL), Centers for Disease Control and Prevention (CDC)]''<ref>{{Cite web | title = http://phil.cdc.gov/phil/details.asp | url = http://phil.cdc.gov/phil/details.asp}}</ref></SMALL>]]
| |
| |-
| |
| | [[File:AnthraxCauses1.jpg|200px|thumb|none| Scanning electron micrograph (SEM) depicted spores from the Sterne strain of Bacillus anthracis bacteria<SMALL>Courtesy: ''[http://phil.cdc.gov/phil/home.asp Public Health Image Library (PHIL), Centers for Disease Control and Prevention (CDC)]''<ref>{{Cite web | title = http://phil.cdc.gov/phil/details.asp | url = http://phil.cdc.gov/phil/details.asp}}</ref></SMALL>]]
| |
| |}
| |
| [[B. anthracis]], the causative agent of anthrax, is a is a nonmotile, [[Gram-positive]], [[aerobic]] or facultatively [[anaerobic]], [[endospore]]-forming, [[rod]]-shaped [[bacterium]] approximately 4 μm by 1 μm, although under the microscope it frequently appears in chains of [[cells]]. Like other Bacillus, [[Bacillus anthracis]] is saprophyte, being able to live in vegetations, air, water and soil.<ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref>
| |
| | |
| These [[bacterial]] [[cells]] may occur isolated, or form groups of 2 or more [[cells]] when in the body, or long chains in cultures.<ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref> In [[blood smear]]s, smears of tissues or lesion fluid from diagnostic specimens, these chains are two to a few cells in length. In smears made from [[in vitro]] cultures, they can appear as endless strings of [[cells]] - responsible for the characteristic tackiness of the colonies and for the flocculating nature of broth cultures.
| |
| | |
| [[B. anthracis]] have a characteristic square-ended appearance traditionally associated with its vegetative state, although this may not always be very clear. In the presence of [[oxygen]], mostly at 32 - 35 ºC, and towards the end of the exponential phase of growth, one ellipsoidal [[spore]] (approximately 2 μm by 1 μm in size) is formed in each [[cell]].<ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref><ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref>
| |
| The [[spores]] of [[B. anthracis]], which can remain dormant in the environment for decades, being resistant to heat and disinfectants, are the [[infectious]] form, but vegetative [[B. anthracis]] rarely causes disease.<ref>{{Cite journal | author = [[Sean V. Shadomy]] & [[Theresa L. Smith]] | title = Zoonosis update. Anthrax | journal = [[Journal of the American Veterinary Medical Association]] | volume = 233 | issue = 1 | pages = 63–72 | year = 2008 | month = July | doi = 10.2460/javma.233.1.63 | pmid = 18593313}}</ref><ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref>
| |
| | |
| In the absence of [[oxygen]] and under a high partial pressure of Co2, in the presence of [[bicarbonate]], the vegetative [[cell]] secretes its [[polypeptide]] [[capsule]] and it is one of the two established [[in vivo]] [[virulence factor]]s of [[B. anthracis]]. The [[capsule]] is also a primary [[diagnostic]] aid.<ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref> Protective [[antigen]] (PA) and [[edema]] factor (EF) combine to form [[edema]] toxin (ET) and PA and lethal factor (LF) combine to form lethal toxin (LT).<ref>{{Cite journal | author = [[Mahtab Moayeri]] & [[Stephen H. Leppla]] | title = The roles of anthrax toxin in pathogenesis | journal = [[Current opinion in microbiology]] | volume = 7 | issue = 1 | pages = 19–24 | year = 2004 | month = February | doi = 10.1016/j.mib.2003.12.001 | pmid = 15036135}}</ref><ref name=CDC>{{cite web | title = Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults | url = http://wwwnc.cdc.gov/eid/article/20/2/13-0687_article }}</ref>
| |
| | |
| ==Origin==
| |
| [[Anthrax]] is thought to have originated in Egypt and Mesopotamia. Many scholars think that in Moses’ time, during the 10 plagues of Egypt, [[anthrax]] may have caused what was known as the fifth [[plague]], described as a sickness affecting horses, cattle, sheep, camels and oxen.
| |
| | |
| ==Tropism==
| |
| | |
| ==Natural Reservoir==
| |
| [[Natural reservoir]]s of [[Bacillus anthracis]] includes:
| |
| * Humans
| |
| * Mammals
| |
| * Herbivores
| |
| * Reptiles
| |
| * Birds
| |
| | |
| ==References==
| |
| {{reflist|2}}
| |
| {{WikiDoc Help Menu}}
| |
| {{WikiDoc Sources}}
| |
|
| |
|
| | [[Category:Emergency mdicine]] |
| [[Category:Disease]] | | [[Category:Disease]] |
| [[Category:Bacterial diseases]] | | [[Category:Up-To-Date]] |
| [[Category:Biological weapons]]
| |
| [[Category:Livestock]]
| |
| [[Category:Zoonoses]]
| |
| [[Category:Medical disasters]]
| |
| [[Category:Infectious disease]] | | [[Category:Infectious disease]] |
| | [[Category:Dermatology]] |
| | [[Category:Pulmonology]] |
| | [[Category:Gastroenterology]] |