Hansen’s disease, commonly known as leprosy, is a condition caused by bacteria that causes nerve damage. The bacteria develops slowly, and therefore can take as many as 20 years after infection before any symptoms appear. The bacteria works by attacking the nerves just under the skin, causing the infected skin to change in color. Because the disease attacks the nerves, one infected with Hansen’s disease may lose feeling and be unable to feel pain, making injuries such as cuts and burns more dangerous. Without treatment, Hansen’s disease can be serious, potentially leading to blindness or impacting the limbs by causing the body to reabsorb fingers or toes. Fortunately, if diagnosed early, Hansen’s disease is treatable with antibiotics. Damage done to the nerves or body parts prior to diagnosis, however, cannot be reversed, and thus early detection is important.

Hansen’s disease is believed to have originated in 1200 CE in present-day India. Mentions of leprosy are present in the Bible (though it is believed to be referencing a different condition entirely), and evidence of leprosy hospitals existed throughout medieval Europe. Hansen’s disease appeared in the United States in the late 19th century, with isolation colonies on the island of Molokai in present-day Hawaii and in Carville, Louisiana, where the novel takes place.