Smallpox has been one of the most dangerous and deadly curses’ ever placed on humankind. Even illnesses as terrible as the plague, cholera, and yellow fever have not had such a universal effect. Smallpox is a parasitic virus (a virus destructive to the host) called variola. It’s considered to be a “crowd disease”, spreading only through people and requiring a large densely populated area to survive. If the virus is cut off from new host bodies it dies out. Smallpox is spread by what is called “droplet infection.” “Droplets” refers to body fluid that escapes into the open air such as moisture does when you sneeze.