OSHA Safety and Health Topic: Smallpox http://www.osha.gov/SLTC/smallpox/index.html
(OSHA)
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Smallpox, also called variola virus, is a highly contagious disease unique to humans. To sustain itself, the virus must pass from person to person in a continuing chain of infection by direct contact or inhalation of air droplets or aerosols.
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