Smallpox

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Smallpox lesions

Variola - major and minor; Variola

Smallpox has two forms: 1) Variola major -- which is a serious illness with a mortality rate according to the CDC of 30% or more, in unvaccinated people, and 2) Variola minor -- a milder infection with a mortality rate of less than 1%. The incubation period for smallpox is approximately 12-14 days. The symptoms are:

• High fever
• Fatigue
• Severe headache
• Backache
• Malaise
• Rash, raised and pink on the skin, starting centrally and spreading outwards. (First the mucosa of the mouth and throat, then face, forearms, trunk, and legs. Rash turns to pus-filled lesions that become crusty on the eighth or ninth day.)
• Delirium
• Vomiting and diarrhea
• Excessive bleeding

• Virus can be seen by electron microscope and by culture.
• Low white blood cell count initially, that increases later in the disease.
• Low platelet count.
• DIC panel can be positive in cases of hemorrhage.
• Antibodies turn positive soon after the infection is complete.

Review Date: 06/09/2005
Reviewed By: Camille Kotton, M.D., Infectious Diseases Division, Massachusetts General Hospital, Boston, MA. Review provided by VeriMed Healthcare Network.