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What was the primary mode of smallpox transmission? Implications for biodefense

Donald K Milton1

  • 1Maryland Institute for Applied Environmental Health, School of Public Health, University of Maryland College Park, MD, USA; Department of Medicine, University of Maryland School of Medicine Baltimore, MD, USA; Department of Environmental Health, Harvard School of Public Health Boston, MA, USA. dmilton@umd.edu

Frontiers in Cellular and Infection Microbiology
|December 11, 2012
PubMed

Insights

Smallpox transmission routes were unclear, with fine particle aerosols potentially playing a significant role. This review explores evidence suggesting aerosol-mediated transmission and its impact on disease severity.

Area of Science:

  • Epidemiology
  • Infectious Disease Transmission
  • Public Health

Background:

  • The primary mode of smallpox transmission remains inconclusive.
  • While respiratory droplet transmission was assumed, the role of aerosols was debated.

Purpose of the Study:

  • To review evidence on smallpox transmission, focusing on the potential role of fine particle aerosols.
  • To explore the concept of anisotropic infection in Variola major.

Main Methods:

  • Review of historical variolation data.
  • Analysis of mucosal infection data from late smallpox transmission periods.
  • Examination of aerosol measurements, animal models, and clinical reports.
  • Epidemiological assessment of smallpox cases.

Main Results:

  • Evidence suggests fine particle aerosols may be important in smallpox transmission.
  • The concept of anisotropic infection, where infection route affects disease severity, is introduced.

Conclusions:

  • Fine particle aerosol-mediated transmission requires further consideration for smallpox.
  • Understanding transmission routes is crucial for effective public health interventions.
Keywords:
air microbiologyairborne infection transmissionbiodefensebioterrorismcommunicable diseasescontact infection transmissionsmallpoxvariola virus

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