Transmission electron micrograph (TEM) of smallpox viruses using a negative stain technique. Smallpox is a serious, highly contagious, and sometimes fatal infectious disease. There is no specific treatment for smallpox disease, and the only prevention is vaccination. Smallpox is a disease which, by 1980, was eradicated by vaccination. The disease causes high fever and skin spots that quickly develop into scarring pustules. The virus is transmitted by coughed droplets of the pus from the pustules of an infected person. Up to 40% of smallpox victims died due to complications such as pneumonia. The virus is now used for purposes of research.