ideo-. a combining form representing idea, in compound words: ideology. Origin of ideo-. ide(a) + -o-.
Smallpox. Smallpox is a disfiguring and potentially deadly infectious disease caused by the Variola major virus. Before smallpox was eradicated, there were two forms of the disease worldwide: Variola major, the deadly disease, and Variola minor, a much milder form.According to some health experts, over the centuries smallpox was responsible for more deaths than all other infectious diseases combined.efore smallpox was eradicated, there were two forms of the disease worldwide: Variola major, the deadly disease, and Variola minor, a much milder form.
Routine smallpox vaccinations stopped in the U.S. and in many other countries in 1972, and in all other World Health Organization member countries by 1986. Many adults living today likely got the vaccine as children. What Causes Smallpox? The variola virus causes it. There are two forms of the virus. The more dangerous form, variola major, led to smallpox disease that killed about 30% of people who were infected. Variola minor caused a less deadly type that killed about 1% of those who got it. How Smallpox Is Spread. The disease is highly contagious.