Smallpox is a brick-shaped virus that is transmitted from one person to another, either through dir...
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Smallpox is a brick-shaped virus that is transmitted from one person to another, either through direct contact or by inhalation. An infected person exhales thousands of virus particles in each breath and inhaling even a few can result in virus infection. A single virus, called a verion, lodges in the throat or upper respiratory tract. The wet mucus membrane binds with the outer envelop of the virus releasing the inner core materials of the verion into the cell. The core of the verion contains the genetic material, or DNA, of the virus. Viral DNA released into the cell becomes a factory for the production of viral proteins and new smallpox vireons. These new veriola viruses are eventually released back into the airway where they are exhaled into the air that other people breathe. Over time, you become more and more contagious. Vireons not exhaled may be attacked by macrophages, one of the body's protection units. The macrophage removes the virus through the lymphatic system, which also becomes infected. The lymphatics dump waste into the circulatory system, which is how the virus moves into the arteries. From there, it is sent to all parts of the body. The virus travels through smaller and smaller arteries until it reaches the capillaries just below the skin. The variola virus infects the cells of the skin, beginning at its deepest layer. Infected cells die and disintegrate. Dead cells collected in the spaces between living skin cells, forming pockets or vesicles. Eventually, a rash appears on the skin's surface over the vesicles. As more materials collect, the vesicles grow. Two days later the skin has developed pustules that are recognizable as pox at the surface. The pustules begin to dry out a few days after that and their rounded tops become flattened and then slightly depressed at the center. Continued drying leads to scab formation. The scab falls away two to four weeks after infection, leaving a small scar or pox mark.