Definition
Smallpox is a viral infection. It is contagious and can be deadly. The disease was eliminated worldwide. This was done through global immunization programs. The last known natural occurring human case was in 1977. Governments have studied its use as a germ-warfare weapon. As a weapon, it would be released in the air. Those exposed could develop the disease. They would then pass it to other people.
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Causes
Variola major is the virus that causes the infection. It is spread:
- Through the airborne droplets of infected saliva
- Between people who have direct contact
- Through the handling of contaminated bed linens or clothing
Two rare, more serious types of the disease are:
- Hemorrhagic
- Malignant
They are transmitted the same way.
Risk Factors
The main risk factor for contracting smallpox is exposure to the virus after its release during a biological terrorism attack.
Symptoms
Symptoms usually occur about 12 days after exposure. Hemorrhagic or malignant symptoms usually do not appear until death is near.
Early symptoms include:
- High fever
- Fatigue
- Severe headache
- Backache
- Possible stomach pain or delirium
- Fatigue
- Sore throat
- Nausea and vomiting
Two to three days later:
- Rash appears on the mouth, throat, face, and arms, then spreads to the legs and trunk
- Red, flat lesions
- Lesions appear at the same time
- Lesions fill with fluid, then pus
- Crusts form during the second week
- Scabs form and fall off after 3-4 weeks
Hemorrhagic symptoms include:
- High fever
- Fatigue
- Headache
- Backache
- Possible stomach pain
- Dark red coloration
- Bleeding into the skin and mucus membranes
Malignant symptoms include:
- High fever
- Fatigue
- Headache
- Backache
- Slowly developing lesions that remain soft and flat
- Skin looks like reddish-colored crepe rubber
- Large amounts of skin may peel, if the patient survives
Diagnosis
The doctor will ask about your symptoms and medical history. A possible source of exposure will be looked for. A physical exam will be done.
Test may include:
- Examination of saliva and fluid from skin lesions under a microscope
- Taking a sample (a culture) of saliva and fluid from skin lesions
- Blood test to detect antibodies to smallpox
Treatment
No effective treatment for smallpox currently exists. Doctors can offer supportive care. Steps will be taken to prevent spread to others.

