The virus was discovered 1796, by Edward Jenner from his observation of the dairy maids. Smallpox is a very serious illness that is caused by a virus called variola. The variola virus multiplies in the cytoplasm of parasitism host cells. Smallpox only naturally infects humans and does not exist in a carrier state. The name is due to the fact that pus-filled blisters form in the duration of the illness. The virus is contagious, it can easily transfer to others through saliva, such as spitting, coughing and sneezing. Smallpox is usually passed with close or face to face contact.

A doctor can recognize the disease because it appears as a special kind of rash. The rash is blisters filled with fluids with a crusty coat over on the skin. The symptoms of smallpox include high fever, severe back ache, head ache, and vomiting.

A vaccine can prevent infection with the virus that cause smallpox. However, there are no known pills that can treat smallpox. Scientists are doing research to try to develop medicine for the disease. If someone does become infected with the smallpox virus, getting the vaccine within a few days of becoming infected can lessen the disease's symptoms.