Even though historians think smallpox was the cause of many epidemics and endemics in history, it is difficult for people to distinguish smallpox from other diseases like syphilis and measles in early writings. The first reliable account of smallpox was by a Persian doctor named Rhazes who described the symptoms of smallpox and contrasted it with measles. Around 570, Bishop Marius of Avicentum coined the Latin word variola (meaning pox) to describe diseases that included smallpox, but it was not until the 1500s that variola became commonly known as "smallpox" to distinguish is with syphilis or the "great pox". ("Smallpox" Encyclopedia Britannica).
By the 17th and 18th centuries, smallpox had frequent epidemics and endemics in Europe, and soon after it spread to the American colonies, Australia and British India as well. It was introduced to them by conquerors that colonized their lands. Smallpox wiped out many Native American populations in United States, Canada, and Australia who had no natural immunity to the disease. It is estimated that disease was responsible for 90% of Native American casualties rather than by military conquer ("Smallpox - Conquered Killer"). Since the beginning of time, people have known that most diseases are contagious. Even though people did not know much about diseases they avoided victims of highly contagious diseases and kept them in isolation so they would not contract the disease as well. Doctors unsuccessfully used procedures such as bloodletting, induced vomiting, and enemas to try and cure infected patients. People also knew that with most diseases, one attack of the disease would give you lifelong immunity to that disease. Early attempts were made to prevent people from getting a severe disease by giving people a mild form of that disease. This is called immunization. The earliest attempts were made by the Chinese who would insert dry crusts from a smallpox pustule into the nose of the person they were trying to protect.
