14. Leptospirosis, suggested to have been one of the key diseases responsible for the annihilation of the native populations of the east coast of North America, can result in the bleeding of the lungs and now infects almost ten million people per year in the developing world
Leptospirosis is a bacterial infection that causes symptoms ranging from mild, including headaches, muscular fatigue, and fevers, to critical, such as bleeding from the lungs, kidney failure, and meningitis. Transmitted by animals, most commonly rodents, to humans, it is frequently imparted through urine making contact with human skin or porous points of entry. First described in 1886 as an “acute infectious disease”, leptospirosis was identified in 1907 and the connection to animals; recognized in 1916. It has since been theorized that leptospirosis was the disease responsible for the exterminating epidemic that swept along the coastline of Massachusetts prior to the Pilgrim’s landing in 1620.
Although vaccinations exist to inoculate animals and prevent the spread of infection, humans are forced to resort to antibiotic modes of treatment. Even with these advanced methods, should the condition lead to more serious symptoms, death rates remain higher than 10 percent. Prominent during the early 20th century, notably in the trenches of World War I, it had been believed that leptospirosis had naturally diminished in frequency due to effective treatment. However, recent years have seen dramatic increases in diagnosis, with an estimated seven to ten million infected annually, typically in sub-Saharan Africa and Southeast Asia, with varying chances of survival.