Category: International EM
Keywords: Smallpox, public health, infectious diseases (PubMed Search)
Posted: 7/19/2014 by Jon Mark Hirshon, MD, MPH, PhD
Click here to contact Jon Mark Hirshon, MD, MPH, PhD
· Smallpox (Variola):
o Only eradicated human infectious disease.
o Prior to the advent of vaccination, it killed an estimated 400,000 Europeans annually and was a major cause of blindness.
· Major potential as a bioterrorism agent:
o Now only supposed to exist in two laboratories in the world (at the CDC in Atlanta, Georgia and in the Vector Institute in Koltsovo, Russia).
· Recently, previously unknown vials of active virus from the 1950s were found in a NIH laboratory in Maryland.
· Clinical Presentation:
o Incubation is usually 10-12 days (range 7-17 days)
o Signs and symptoms include:
§ Febrile (38.8-40.0C) prodome lasting 1-4 days, headache, myalgia (esp. back/spinal pain), pharyngitis, chills, abdominal pain
§ Rash: classically round and well circumscribed. May be confluent or umbilicated. The rash evolves slowly: macules to papules to pustules to scabs.
· It is important to differentiate smallpox from chicken pox (Varicella):
o Smallpox: Significant prodrome. Centrifugal rash (trunk to extremities). Can involve soles and palms. Lesions are in the same stage of development on any one part of the body.
o Chickenpox: Minimal prodrome. Centripetal rash (extremities to trunk). Seldom on soles and palms. Asynchronus evolution of rash.
Bottom Line:
Smallpox is a global public health emergency and requires immediate reporting. If the clinical presentation is unclear, discuss with local infectious disease experts or public health officials.
