Smallpox was a dangerous disease with a high mortality rate. It no longer exists as an epidemic disease. The last naturally occurring case was diagnosed in October 1977. The World Health Organization (WHO) certified the global eradication of the disease in 1980 (said there was no more).
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Child infected with smallpox. Bangladesh, 1973. In ordinary type smallpox the bumps are filled with a thick, opaque fluid and often have a depression or dimple in the center. This is a major distinguishing characteristic of smallpox.
It was caused by a virus. There are two different species of viruses that can cause the disease. They are Variola major and Variola minor. Some people also call smallpox Variola, from the Latin work for "spotted" which is also the viruses' scientific name.
Only humans can get this disease, but it probably came a virus which infected animals. Variola major killed between 20% and 40% of those who got it. Variola minor killed only about 1%. Many people who survived become blind because of the damage the virus did to the eyes.
During the first half of the 20th century, between 300 million and 500 million people died of this disease. Even in 1967, about 15 million people caught the disease, and about two million people died of it, according to the World Health Organization (WHO).
The first vaccine for smallpox used the results of cowpox infections. It was invented by Edward Jenner. It was used to stop people from getting smallpox. The word "vaccine" came from "vaccina", the Latin word for cow, because cowpox was used. The WHO (World Health Organisation) vaccinated people all over the world. In 1980, the WHO said the disease no longer existed, and no one would ever get sick from it again. Live copies of smallpox are kept in maximum-security laboratories around the world.
Some people believe that smallpox could be used as an agent for purposely infecting enemies in a war. Today, most people no longer receive a smallpox shot.