Smallpox is an extremely virulent and often fatal disease caused by the Variola virus. Two primary forms of the disease, Variola major and Variola minor have similar signs and symptoms. Variola major is fatal in 30 percent of those infected while Variola minor is fatal in less than 1 percent. Smallpox is a systemic infection, affecting all parts of the body, but is noted for it's profound and often disfiguring effects on the skin and themucosa.

Initial Infection

Smallpox is spread by direct and long-term exposure to the host. Clothing, bedding materials and other items that come in contact with the host, as well as body fluids, can carry smallpox. Smallpox infections begin with a high fever, head and body aches, general malaise and occasional vomiting. The fever will usually range from between 101 F and 104 F.

Tongue and Mouth

The tongue and the inside of the mouth will present with tiny red dots that will progress to open sores which will shed the virus from the mucosa into the mouth, thereby spreading the disease further throughout the body.

Immune and Circulatory Systems

The disease will proliferate in the body through the circulatory system. It inevitably compromises the immune system by killing large numbers of macrophages, defensive cells within the body, which the virus uses to reproduce. The disease will also attack the blood vessels within the skin.

Internal Organs

During the initial incubation period, the circulatory system carries the virus to the rest the body where it reproduces primarily within the spleen and the bone marrow as well as in other organs, including the lungs and liver. It is interesting to note that smallpox does not seem to cause lesions anywhere in the body other than on the skin and within the mucosa.

Skin

Initially, a rash will appear on the skin. It will first affect the face then the torso and extremities. Raised bumps will then appear within the rash. The bumps will eventually become raised pustules that are firm to the touch and round. Later, the pustules will begin to ooze, forming a crust and eventually scabbing over. Inevitably, the scabs will fall off and scars will form.

Another form of the disease, known as mailgnant smallpox, produces flat lesions, rather than the raised bumps typical of the Variola major and minor. Hemorrhagic smallpox results in significant bleeding within the skin. Both of these forms of the disease are almost always fatal.