Smallpox: Difference between revisions

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*Caused by the variola virus<ref>Rosen, Peter, John A. Marx, Robert S. Hockberger, and Ron M. Walls. "Smallpox." Rosen's Emergency Medicine Concepts and Clinical Practice. 8th ed. Vol. 2. Philadelphia, PA: Elsevier/Saunders, 2013. 1579-1580.</ref>
*Caused by the variola virus<ref>Rosen, Peter, John A. Marx, Robert S. Hockberger, and Ron M. Walls. "Smallpox." Rosen's Emergency Medicine Concepts and Clinical Practice. 8th ed. Vol. 2. Philadelphia, PA: Elsevier/Saunders, 2013. 1579-1580.</ref>
*Passed through direct contact with the person, with body fluids, as well as with airborne droplets of an infected, symptomatic person  
*Passed through direct contact with the person, with body fluids, as well as with airborne droplets of an infected, symptomatic person  
**Can survive for 24-48 hours in the environment
*Most infectious during the first week of symptoms, but will remain infectious until the last pox scab falls off  
*Most infectious during the first week of symptoms, but will remain infectious until the last pox scab falls off  
*Humans are the only known host<ref>Barquet, Nicolau, MD, and Pere Domingo, MD. "Smallpox: The Triumph over the Most Terrible of the Ministers of Death." Annals of Internal Medicine 127 (1997): 635-42.</ref>
*Humans are the only known host<ref>Barquet, Nicolau, MD, and Pere Domingo, MD. "Smallpox: The Triumph over the Most Terrible of the Ministers of Death." Annals of Internal Medicine 127 (1997): 635-42.</ref>
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*There are stocks of the virus in 2 laboratories – one in Atlanta, Georgia, USA and one in Moscow, Russia
*There are stocks of the virus in 2 laboratories – one in Atlanta, Georgia, USA and one in Moscow, Russia
*There are concerns some laboratories may illegally have the virus and could release it as a weapon of bioterrorism<ref>Anderson PD. Bokor G. Bioterrorism: pathogens as weapons. J Pharm Pract. 2012 Oct;25(5):521-9.</ref>
*There are concerns some laboratories may illegally have the virus and could release it as a weapon of bioterrorism<ref>Anderson PD. Bokor G. Bioterrorism: pathogens as weapons. J Pharm Pract. 2012 Oct;25(5):521-9.</ref>
**This was attempted by British soldiers in 1763 by throwing blankets from people with smallpox to the American Indians
*It is considered a potential bioterrorism threat as most people are now considered to be vulnerable to the virus because vaccination programs have stopped
*In July 2014, 2 vials of smallpox were unknowingly discovered at the National Institutes of Health in Bethesda, Maryland leading to heightened concerns that there may be more stockpiles in the world<ref>"Smallpox, Smallpox FAQ." WHO | World Health Organization. http://www.who.int/csr/disease/smallpox/en/ & http://www.who.int/csr/disease/smallpox/faq/en/</ref>
*Many proposals have been made to destroy all the remaining vials of smallpox and related viruses, but as of yet the virus remains in those 2 laboratories


===Vaccination History===
===Vaccination History===
*The vaccine “vaccinia variola” was made from a closely-related virus
*The vaccine “vaccinia variola” was made from a closely-related virus
*Discovered by Edward Jenner who found out that the milkmaids who had been exposed to cowpox were immune to smallpox
*Vaccination is considered successful if at least one pustule forms at the injection site  
*Vaccination is considered successful if at least one pustule forms at the injection site  
*Does have serious side effects, especially in the immunocompromised, including death in rare cases
*Does have serious side effects, especially in the immunocompromised, including death in rare cases
*Due to the side effects and the current eradication, it is not used anywhere in the world currently
*Due to the side effects and the current eradication, it is not used anywhere in the world currently
*Many governments have large stockpiles of the vaccinia vaccine and plans in place for rapid response and vaccination if an outbreak were to occur  
**Only select groups of individuals will be vaccinated, including some members of the US military (depending on where they are deployed) <ref> http://www.usamma.amedd.army.mil/net/assets/doc/pdf/Vaccines/SVP_Q_A_8July2014.pdf </ref>
*Many governments have large stockpiles of the vaccinia vaccine and plans in place for rapid response and vaccination if an outbreak were to occur


==Clinical Features==
==Clinical Features==
[[File:Child with Smallpox Bangladesh.jpg|thumbnail|Child with Smallpox]]
[[File:PMC3223485 eplasty11e47 fig1.png|thumb|Man with small pox displaying the characteristic rash.]]
*Incubation period: 7-19 days  
*Incubation period: 7-19 days  
*Initial phase begins as a fever, fatigue/weakness, dorsal-lumbar pain, myalgias, nausea/vomiting
*Initial phase begins as a fever, fatigue/weakness, dorsal-lumbar pain, myalgias, nausea/vomiting
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**Lesions will generally all be at same stage  
**Lesions will generally all be at same stage  
**Lesions begin as clear fluid-filled vesicles, progress to pustules, and then harden and form a crust, ultimately falling off in about 3-4 weeks
**Lesions begin as clear fluid-filled vesicles, progress to pustules, and then harden and form a crust, ultimately falling off in about 3-4 weeks
*Several different disease courses
 
**Variola minor – most common form of the disease, described above
===Clinical Forms===
**Variola fulminans – rapid death during the initial phase
*Variola major and minor (90% of cases)
**Variola confluens – initial maculopapular rash becomes confluent leading to 96% mortality
**Variola major
**Variola hemorrhagica – hemorrhages occur within the blisters as well as mucus membranes and internal organs, death usually occurs during the first 24 hours
***More severe, mortality rate 30%
[[File:Child with Smallpox Bangladesh.jpg|thumbnail|Child with Smallpox]]
**Variola minor
***Less severe, mortality rate 1%
***Fewer pox
*Other (10% of cases)
**Hemorrhagic
***Hemorrhages occur within the blisters as well as mucus membranes and internal organs, death usually within 5-6 days
**Malignant
***Soft, flattened lesions, does not progress to pustules
***Resolve without forming scabs <ref> Schultz, C., & Koenig, K. Weapons of Mass Destruction. In Rosen's Emergency Medicine: Concepts and Clinical Practice (9th ed.). Philadephia, PA: Elsevier/Saunders. </ref>


==Differential Diagnosis==
==Differential Diagnosis==
===Pediatric Rashes===
{{Peds Rash DDX}}
{{Peds Rash DDX}}
 
{{Bullous rashes DDX}}
{{Bioterrorism agents}}
{{Bioterrorism agents}}


==Diagnosis==
==Evaluation==
*Clinical diagnosis based on symptoms and characteristic rash
*Clinical diagnosis based on symptoms and characteristic rash
*PCR DNA test
*PCR DNA test
*When the disease was present, either electron microscopy of stained crusts of lesions or a slide precipitation method was used
*When the disease was present, either electron microscopy of stained crusts of lesions or a slide precipitation method was used


==Treatment==
==Management==
{{Smallpox Treatment}}
{{Smallpox Treatment}}


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**due to viral shedding
**due to viral shedding


===Isolation ===
===Isolation===
*Airborne and contact isolation with negative pressure
*Airborne and contact isolation with negative pressure
*Personal protective wear level D with N95 respirator
*Personal protective wear level D with N95 respirator
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[[Category:ID]]
[[Category:ID]]
[[Category:Tox]]
[[Category:Toxicology]]

Latest revision as of 16:14, 7 September 2022

Background

  • Caused by the variola virus[1]
  • Passed through direct contact with the person, with body fluids, as well as with airborne droplets of an infected, symptomatic person
    • Can survive for 24-48 hours in the environment
  • Most infectious during the first week of symptoms, but will remain infectious until the last pox scab falls off
  • Humans are the only known host[2]
  • Declared eradicated in 1980 after a global immunization campaign from 1966-1980; last known natural case was in Somalia in 1977; last known cases were in England in 1978 after a laboratory accident[3]

Bioterrorism

  • There are stocks of the virus in 2 laboratories – one in Atlanta, Georgia, USA and one in Moscow, Russia
  • There are concerns some laboratories may illegally have the virus and could release it as a weapon of bioterrorism[4]
  • It is considered a potential bioterrorism threat as most people are now considered to be vulnerable to the virus because vaccination programs have stopped

Vaccination History

  • The vaccine “vaccinia variola” was made from a closely-related virus
  • Vaccination is considered successful if at least one pustule forms at the injection site
  • Does have serious side effects, especially in the immunocompromised, including death in rare cases
  • Due to the side effects and the current eradication, it is not used anywhere in the world currently
    • Only select groups of individuals will be vaccinated, including some members of the US military (depending on where they are deployed) [5]
  • Many governments have large stockpiles of the vaccinia vaccine and plans in place for rapid response and vaccination if an outbreak were to occur

Clinical Features

Child with Smallpox
Man with small pox displaying the characteristic rash.
  • Incubation period: 7-19 days
  • Initial phase begins as a fever, fatigue/weakness, dorsal-lumbar pain, myalgias, nausea/vomiting
  • 2-4 days later the characteristic rash appears
    • Worst on the face, arms, legs, and includes the palms and soles
    • Lesions will generally all be at same stage
    • Lesions begin as clear fluid-filled vesicles, progress to pustules, and then harden and form a crust, ultimately falling off in about 3-4 weeks

Clinical Forms

  • Variola major and minor (90% of cases)
    • Variola major
      • More severe, mortality rate 30%
    • Variola minor
      • Less severe, mortality rate 1%
      • Fewer pox
  • Other (10% of cases)
    • Hemorrhagic
      • Hemorrhages occur within the blisters as well as mucus membranes and internal organs, death usually within 5-6 days
    • Malignant
      • Soft, flattened lesions, does not progress to pustules
      • Resolve without forming scabs [6]

Differential Diagnosis

Pediatric Rash

Vesiculobullous rashes

Febrile

Afebrile

Bioterrorism Agents[7]

Category A

Category B

  • Ricin
  • Brucellosis
  • Epsilon toxin
  • Psittacosis
  • Q Fever
  • Staph enterotoxin B
  • Typhus
  • Glanders
  • Melioidosis
  • Food safety threats
  • Water safety threats
  • Viral encephalitis

Category C

Evaluation

  • Clinical diagnosis based on symptoms and characteristic rash
  • PCR DNA test
  • When the disease was present, either electron microscopy of stained crusts of lesions or a slide precipitation method was used

Management

  • IMMEDIATE NOTIFICATION OF PUBLIC HEALTH AUTHORITIES
  • Vaccine administered up to 3 days post-exposure was effective in preventing infection as well as lessening the severity of the disease if infection occurred [8]

Post-Exposure Prophylaxis

  • Vaccinia Vaccine (administer within 72hrs of exposure)

Active Disease

  • Supportive care and wound care for open lesions
  • Vaccinia Vaccine within the first 72hrs can decrease total disease severity and within 7 days may decrease symptoms
    • Vaccination is not efficacious once the patient has developed rash[9]

Vaccinia Vaccine Complications

Contraindications for administration include:

  • Pregnancy
  • Severe cardiac disease
  • Immunocompromise
  • Same living quarters as other person with above contraindications
    • due to viral shedding

Isolation

  • Airborne and contact isolation with negative pressure
  • Personal protective wear level D with N95 respirator


See Also

Bioterrorism

References

  1. ↑ Rosen, Peter, John A. Marx, Robert S. Hockberger, and Ron M. Walls. "Smallpox." Rosen's Emergency Medicine Concepts and Clinical Practice. 8th ed. Vol. 2. Philadelphia, PA: Elsevier/Saunders, 2013. 1579-1580.
  2. ↑ Barquet, Nicolau, MD, and Pere Domingo, MD. "Smallpox: The Triumph over the Most Terrible of the Ministers of Death." Annals of Internal Medicine 127 (1997): 635-42.
  3. ↑ Ellner, P. D. "Smallpox: Gone but Not Forgotten." Infection 26.5 (1998): 263-69.
  4. ↑ Anderson PD. Bokor G. Bioterrorism: pathogens as weapons. J Pharm Pract. 2012 Oct;25(5):521-9.
  5. ↑ http://www.usamma.amedd.army.mil/net/assets/doc/pdf/Vaccines/SVP_Q_A_8July2014.pdf
  6. ↑ Schultz, C., & Koenig, K. Weapons of Mass Destruction. In Rosen's Emergency Medicine: Concepts and Clinical Practice (9th ed.). Philadephia, PA: Elsevier/Saunders.
  7. ↑ https://www.niaid.nih.gov/topics/biodefenserelated/biodefense/pages/cata.aspx Accessed 02/26/16
  8. ↑ Kman NE, Nelson RN. Infectious agents of bioterrorism: a review for emergency physicians. Emerg Med Clin North Am. 2008 May;26(2):517-47
  9. ↑ Cdc.gov. 2020. Prevention and Treatment | Smallpox | CDC. [online] Available at: <https://www.cdc.gov/smallpox/prevention-treatment/index.html> [Accessed 11 September 2021].
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