|
Smallpox is a highly contagious viral disease unique to humans. It is caused by two virus variants called Variola major and Variola minor. V. major is the more deadly form, with a typical mortality of 20 to 40 percent of those infected. The other type, V. minor, only kills 1% of its victims. Many survivors are left blind in one or both eyes from corneal ulcerations, and persistent skin scarring pockmarks is nearly universal. Smallpox was responsible for an estimated 300 to 500 million deaths in the 20th century. As recently as 1967, the World Health Organization (WHO) estimated that 15 million people contracted the disease and that two million died in that year. |
