Smallpox Signs and Symptoms
After infection, symptoms may take from seven to 17 days to appear for major types of smallpox. The virus begins growing in the bloodstream 72-96 hours after infection, but no obvious symptoms appear immediately (see multimedia files below for clinical presentations of smallpox infections).
- People who have contracted smallpox initially develop such symptoms as fever, body aches, headache, chills, and, particularly, backache. Over half of people with smallpox experience chills and vomiting. Some become confused.
- A rash appears 48-72 hours after the initial symptoms and turns into virus-filled sores, which later scab over. The process can take up to two weeks.
- Just after the rash appears, the virus is highly contagious as it moves into the mucous membranes. The body sheds the cells, and virus particles are released, coughed, or sneezed into the environment. The infected person can be infectious for up to three weeks (until the scabs fall off the rash). Live virus can be present in the scabs. After the scabs or crusts fall off (in two to four weeks), a depression or light-skinned scar remains.
- Early in the course of the disease, the rash and pus-filled sores can easily be mistaken for chickenpox. Lesions occur first in the mouth and spread to the face, then to the forearms and hands, and finally to the lower limbs and trunk. In contrast, rash from chickenpox progresses from the arms and legs to the trunk and rarely forms in the armpits, palms, soles, and elbow areas.
Medically Reviewed by a Doctor on 3/3/2015
Must Read Articles Related to Smallpox
Biological weapons include any organism (such as bacteria, viruses, or fungi) or toxin found in nature that can be used to kill or injure people.learn more >>
Fever in Adults
A fever is a body temperature of 100.4 F or greater. A fever may be caused by a virus, bacteria, fungus, blood clot, tumor, drug, or the environment. Treatment ...learn more >>
Fever in Children
Fever is defined as a rectal temperature over 100.4 F or 38.0 C. Fever isn't life-threatening unless it is persistently high -- greater than 107 F rectal temper...learn more >>
Patient Comments & Reviews
The eMedicineHealth doctors ask about Smallpox: