PetriKey

Virus

Variola virus

Smallpox agent, eradicated in 1980

vuh-RY-oh-luh VY-rus

dna-viruspoxviruseradicatedorthopoxvirushistoricalbiosafety

High-yield clue

Smallpox, caused by variola, was declared eradicated by the WHO in 1980 after a global vaccination campaign.

Overview

The large double-stranded DNA orthopoxvirus that historically caused smallpox; it is studied as the only human disease declared eradicated and as a landmark in vaccination and public-health history.

Classification

  • DNA virus
  • Double-stranded DNA
  • Cytoplasmic replication
  • Family Poxviridae, genus Orthopoxvirus

Lab & identification clues

  • Orthopoxvirus classification concept
  • Guarnieri inclusion body historical concept
  • Synchronous same-stage rash description (historical)
  • High-containment biosafety framing

Associations

  • Declared eradicated by WHO in 1980
  • Vaccinia-based vaccination eradication history
  • Known live stocks retained at two WHO reference centers
  • Foundational example of herd immunity and eradication

Commonly confused with

  • Varicella-zoster virus (chickenpox)
  • Mpox (monkeypox virus)

Your notes

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource