Smallpox is a contagious, disfiguring and often deadly disease that has affected humans for thousands of years. Naturally occurring smallpox was eradicated worldwide by 1980 the result of an unprecedented global immunization campaign.

Samples of smallpox virus have been kept for research purposes. This has led to concerns that smallpox could someday be used as a biological warfare agent.

No cure or treatment for smallpox exists. A vaccine can prevent smallpox, but the risk of the vaccine's side effects is too high to justify routine vaccination for people at low risk of exposure to the smallpox virus.

Symptoms Causes Complications Prevention

The first symptoms of smallpox usually appear 12 to 14 days after you're infected. During the incubation period of seven to 17 days, you look and feel healthy and can't infect others.

Following the incubation period, a sudden onset of flu-like signs and symptoms occurs. These include:

  • Fever
  • Overall discomfort
  • Headache
  • Severe fatigue
  • Severe back pain
  • Vomiting, possibly

A few days later, flat, red spots appear first on your face, hands and forearms, and later on your trunk. Within a day or two, many of these lesions turn into small blisters filled with clear fluid, which then turns into pus. Scabs begin to form eight to nine days later and eventually fall off, leaving deep, pitted scars.

Lesions also develop in the mucous membranes of your nose and mouth and quickly turn into sores that break open.

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