Describe one major infectious in history. need details, you.

Smallpox:

The earliest credible evidence of smallpox is found in the Egyptian mummies of people who died some 3000 years ago.[2] Smallpox has had a major impact on world history, not least because indigenous populations of regions where smallpox was non-native, such as the Americas and Australia, were rapidly decimated and weakened by smallpox (along with other introduced diseases) during periods of initial foreign contact, which helped pave the way for conquest and colonization. During the 18th century the disease killed an estimated 400,000 Europeans each year, including five reigning monarchs, and was responsible for a third of all blindness.[3] Between 20 and 60% of all those infected—and over 80% of infected children—died from the disease

If you get a map and put the countries a states all together it forms all one piece you can also tell because of the earth quakes