Smallpox is viewed as the most likely agent to be used as a biological weapon. Smallpox is very infectious; it is spread by droplet infection, causes a painful and disabling febrile disease, has ...

Orthopoxvirus: Genus of DNA viruses that includes variola (smallpox), monkeypox, cowpox, and vaccinia. Progressive vaccinia: Progressive necrosis of the primary vaccination site with spread of ...

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