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.
1 Smallpox: Smallpox is a serious, contagious, and sometimes fatal infectious disease caused by the variola virus. 2  Historically, smallpox had a mortality rate of as much as 30 percent. 3  In the Americas, it killed as much as 90 percent of the indigenous population after contact with Europeans introduced the disease. Smallpox: Smallpox is a serious, contagious, and sometimes fatal infectious disease caused by the variola virus. 2  Historically, smallpox had a mortality rate of as much as 30 percent. 3  In the Americas, it killed as much as 90 percent of the indigenous population after contact with Europeans introduced the disease.