Difference between revisions of "Bacillus anthracis"

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==''Bacillus anthracis'' - Anthrax==
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=Hosts=
 
 
===Hosts===
 
 
This bacterium infects multiple types of hosts including herbivorous mammals such as livestock and is considered zoonotic however humans are a dead end host and do not become infectious.
 
This bacterium infects multiple types of hosts including herbivorous mammals such as livestock and is considered zoonotic however humans are a dead end host and do not become infectious.
  
===Transmission/Exposure Routes===
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=Transmission/Exposure Routes=
Cutaneous: skin contact with spores from infected animals.<br />  
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Cutaneous: skin contact with spores from infected animals (95% of Cases; Most in Africa, Asia, and eastern Europe).<br />  
 
Gastrointestinal: eating poorly cooked meat/dairy from infected animal. <br />
 
Gastrointestinal: eating poorly cooked meat/dairy from infected animal. <br />
 
Inhalation: Inhalation of spores<br />
 
Inhalation: Inhalation of spores<br />
Injectional: soft tissue infection associated with injection drug use <br/> ([http://www.springerlink.com.proxy2.cl.msu.edu/content/136q4u1j54743815/fulltext.pdf Int Care Med]) <br/>
+
Injectional: soft tissue infection associated with injection drug use <br/> <ref name=IntCareMed>[http://www.springerlink.com.proxy2.cl.msu.edu/content/136q4u1j54743815/fulltext.pdf Int Care Med]</ref> <br/>
 
Anthrax is not contagious and cannot be transmitted from person-to-person. <ref name=Brookmeyer></ref>
 
Anthrax is not contagious and cannot be transmitted from person-to-person. <ref name=Brookmeyer></ref>
  
===Case fatality ratio ===
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=Case fatality ratio =
{|                                                  
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{| class="wikitable" style="text-align:left;"                                                  
{| border = "1"
 
 
|+ '''Case fatality ratios'''                                   
 
|+ '''Case fatality ratios'''                                   
 
|-
 
|-
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| Not Reported
 
| Not Reported
 
| <ref name=CDC></ref>
 
| <ref name=CDC></ref>
 +
|-
 +
| 89%
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| Inhalation
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| Occupationally Acquired: 20th century untreated
 +
| <ref name=IntCareMed></ref>
 
|-
 
|-
 
| 45%
 
| 45%
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| 65% (13 of 20)
 
| 65% (13 of 20)
 
| Gastrointestinal
 
| Gastrointestinal
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| Children 1900-2005
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| <ref name=Bravata></ref>
 +
|-
 +
| 100%
 +
| Gastrointestinal
 +
| Unreported
 +
| <ref name=IntCareMed></ref>
 +
|-
 +
| 100% (6 of 6)
 +
| primary meningoencephalitis
 
| Children 1900-2005
 
| Children 1900-2005
 
| <ref name=Bravata></ref>
 
| <ref name=Bravata></ref>
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| <ref name=Kaya>Kaya A, Tasyaran M, Erol S, Ozkurt Z, and Ozkan B. (2002) Anthrax in Adults and Children: A Review of 132 Cases in Turkey. Eur J Clin Microbiol Infect Dis. 21: 258-261. [http://www.springerlink.com/content/v8ctc3ajmnwxhryn/fulltext.pdf Full Text]</ref>
 
| <ref name=Kaya>Kaya A, Tasyaran M, Erol S, Ozkurt Z, and Ozkan B. (2002) Anthrax in Adults and Children: A Review of 132 Cases in Turkey. Eur J Clin Microbiol Infect Dis. 21: 258-261. [http://www.springerlink.com/content/v8ctc3ajmnwxhryn/fulltext.pdf Full Text]</ref>
 
|-
 
|-
 +
| 30% (3 of 10)
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| Injectional
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| Adults aged 23-53, UK
 +
| <ref name=IntCareMed></ref>
 +
|-
 +
 
|}
 
|}
 
|}
 
|}
  
===Incubation Times===
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=Incubation Times=
{|                                                  
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{| class="wikitable" style="text-align:left;"
{| border = "1"
 
 
|+ '''Incubation Times'''
 
|+ '''Incubation Times'''
 
|-
 
|-
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|}
 
|}
  
===Burden of Disease===
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=Burden of Disease=
  
  
 
====Duration of infectiousness and disease====
 
====Duration of infectiousness and disease====
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Gastrointestinal: 10-14 days<ref name=IntCareMed></ref>
 +
====Symptomology====
 +
Cutaneous: <br/>
 +
*Primary skin lesion 3-5 days after infection is painless puriritic papule.
 +
*Lesion forms a necrotic vesicle leaving a black eschar surrounded by edma.
 +
*Eschar dries and sloughs in next 1-2 weeks.
 +
<br/>
 +
Gastrointestinal: <br/>
 +
*Oral-pharyngeal form: oral or esophageal ulcer with regional lymphadenopathy edema and sepsis
 +
*Lower GI form: primary intestinal lesions predominantly in terminal ileum or cecum. Nausea, vomiting, malaise, bloody diarrhea, acute abdomen, and sepsis are common symptoms of the Lower GI form.
 +
<br/>
 +
Inhalational: <br/> Two-stages
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*1: Flu-like symptoms including cough fever, fatigue that last from hours to a few days
 +
*2: Rising fever, dyspnea, diaphoresis, shock. In advanced form, cyanosis and hypotension progress rapidly and death can occur within hours
 +
<br/>
 +
Injectional: <br/>
 +
*Tissue swelling around the injection site
 +
*Abdominal symptoms<ref name=IntCareMed></ref>
 +
  
====Symptomology====
 
Flu-like symptoms including:
 
Fever (temperature greater than 100 degrees F). The fever may be accompanied by chills or night sweats.
 
Cough, usually a non-productive cough, chest discomfort, shortness of breath, fatigue, muscle aches
 
Sore throat, followed by difficulty swallowing, enlarged lymph nodes, headache, nausea, loss of appetite, abdominal distress, vomiting, or diarrhea
 
   
 
 
====Excretion Rates  (see Exposure)====
 
====Excretion Rates  (see Exposure)====
 
Spores are cleared from the lung at a rate between 8-14% per day. <ref name=Brookmeyer></ref>
 
Spores are cleared from the lung at a rate between 8-14% per day. <ref name=Brookmeyer></ref>
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Anthrax vaccination consists of 5 total intramuscular injections, followed by recommended annual boosters to maintain immunity. <ref name=CDC></ref>
 
Anthrax vaccination consists of 5 total intramuscular injections, followed by recommended annual boosters to maintain immunity. <ref name=CDC></ref>
  
===Microbiology===
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=Microbiology=
Gram +, aerobic, encapsulated, nonmotile. Exists in a dormant spore or an actively replicating vegetative rod form Extremely hardy spores can persist for years, even decades. ([http://www.springerlink.com.proxy2.cl.msu.edu/content/136q4u1j54743815/fulltext.pdf Intensive Care Med])
+
Gram +, aerobic, encapsulated, nonmotile. Exists in a dormant spore or an actively replicating vegetative rod form Extremely hardy spores can persist for years, even decades.<ref name=IntCareMed></ref>
 +
 
  
===Envrionmental Survival===
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=Envrionmental Survival=
  
  
===Recommended Dose Response model===
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=Recommended Dose Response model=
[[has DR model::Dose response models for Bacillus anthracis]]
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[[Bacillus anthracis: Dose Response Models]]
 
<br />
 
<br />
 
Exponential model: optimal value of k is 1.65E-05 [[File:Exponential_model.png|thumb|left|200px]]
 
Exponential model: optimal value of k is 1.65E-05 [[File:Exponential_model.png|thumb|left|200px]]
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 +
 +
<headertabs />
  
 
===References===
 
===References===
 
 
<references/>
 
<references/>
http://en.wikipedia.org/wiki/Anthrax <br/>
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[[Category:Bacterium]][[Category:BT category A]][[Category:Agent Overview]]
[http://www.springerlink.com.proxy2.cl.msu.edu/content/136q4u1j54743815/fulltext.pdf Int Care Med] <br/>
 
[[Category:PSDS]]
 
[[Category:Bacterium]][[Category:BT category A]]
 

Latest revision as of 16:57, 3 July 2013

[edit]

This bacterium infects multiple types of hosts including herbivorous mammals such as livestock and is considered zoonotic however humans are a dead end host and do not become infectious.

Cutaneous: skin contact with spores from infected animals (95% of Cases; Most in Africa, Asia, and eastern Europe).
Gastrointestinal: eating poorly cooked meat/dairy from infected animal.
Inhalation: Inhalation of spores
Injectional: soft tissue infection associated with injection drug use
[1]
Anthrax is not contagious and cannot be transmitted from person-to-person. [2]

Case fatality ratios
Case Fatality Ratio Pathway/conditions Population References
1% Cutaneous with treatment General US Population [3]
20% Cutaneous without treatment General US population [3]
75% Inhalation despite treatment Not Reported [3]
89% Inhalation Occupationally Acquired: 20th century untreated [1]
45% 2001 US Attack Adult US [4]
14% (5 of 37) Cutaneous Children 1900-2005 [5]
60% Inhalation Children 1900-2005 [5]
65% (13 of 20) Gastrointestinal Children 1900-2005 [5]
100% Gastrointestinal Unreported [1]
100% (6 of 6) primary meningoencephalitis Children 1900-2005 [5]
100% (6 of 6) primary meningoencephalitis Children 1900-2005 [5]
1.5% (of 132) Not reported Hospitalized adults and children, Turkey 1986 to 2000 [6]
30% (3 of 10) Injectional Adults aged 23-53, UK [1]

|}

Incubation Times
Days Pathway Population Reference
0-1 Cutaneous Not Reported [3]
1-7 days Inhalation

Ingestion

Not Reported [3]
60 (max) Inhalation

Ingestion

Not Reported [3]
10 Days (SD: 8.67) Inhalation Sverdlovsk 1979 outbreak (70 cases) [2]

Duration of infectiousness and disease

Gastrointestinal: 10-14 days[1]

Symptomology

Cutaneous:

  • Primary skin lesion 3-5 days after infection is painless puriritic papule.
  • Lesion forms a necrotic vesicle leaving a black eschar surrounded by edma.
  • Eschar dries and sloughs in next 1-2 weeks.


Gastrointestinal:

  • Oral-pharyngeal form: oral or esophageal ulcer with regional lymphadenopathy edema and sepsis
  • Lower GI form: primary intestinal lesions predominantly in terminal ileum or cecum. Nausea, vomiting, malaise, bloody diarrhea, acute abdomen, and sepsis are common symptoms of the Lower GI form.


Inhalational:
Two-stages

  • 1: Flu-like symptoms including cough fever, fatigue that last from hours to a few days
  • 2: Rising fever, dyspnea, diaphoresis, shock. In advanced form, cyanosis and hypotension progress rapidly and death can occur within hours


Injectional:

  • Tissue swelling around the injection site
  • Abdominal symptoms[1]


Excretion Rates (see Exposure)

Spores are cleared from the lung at a rate between 8-14% per day. [2]

Immunity

Anthrax vaccination consists of 5 total intramuscular injections, followed by recommended annual boosters to maintain immunity. [3]

Gram +, aerobic, encapsulated, nonmotile. Exists in a dormant spore or an actively replicating vegetative rod form Extremely hardy spores can persist for years, even decades.[1]


References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Int Care Med
  2. 2.0 2.1 2.2 Brookmeyer, R., Johnson, E., & Barry, S. (2005). Modelling the incubation period of anthrax. Statistics in Medicine, 24(4), 531–542. doi:10.1002/sim. Full Text
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 CDC
  4. Holty J, Bravata D, Liu H, Olshen R, Mcdonald K, and Owens D. (2006) Systematic Review: A Century of Inhalational Anthrax Cases from 1900 to 2005. Annals of Internal Medicine. 144, 4. 270-280. Full Text
  5. 5.0 5.1 5.2 5.3 5.4 Bravata D, Holty J, Wang E, Lewis R, Wise P, McDonald K, and Owen D. (2007) Inhalational, Gastrointestinal, and Cutaneous Anthrax in Children. Arch Pediatr Adolesc Med. 161 (9): 896-905. Full Text
  6. Kaya A, Tasyaran M, Erol S, Ozkurt Z, and Ozkan B. (2002) Anthrax in Adults and Children: A Review of 132 Cases in Turkey. Eur J Clin Microbiol Infect Dis. 21: 258-261. Full Text