In 1917, syphilis was a deadly disease. Associated with immoral behavior, such as regular visits to a brothel, the disease had no cure and in its latent stage (which could be anywhere from one to 20 years after infection), the spirochete that caused the disease would enter the central nervous system, including the brain, and cause personality change, psychosis, depression, dementia, and death.
Unfortunately innocent people could catch the disease; for instance, a wife whose husband had visited a local brothel.
Though the disease is now easily treated with antibiotics, in 1917, it had no cure except for a chemical treatment called Salvarsan, which contained arsenic, which lead to considerable side effects, as you can imagine.
One enterprising Viennese neurologist, who is described as a not-so-nice person (he eventually won a Nobel Prize in medicine), noticed that the syphilis spirochete died in high heat. He devised a treatment called “pyrotherapy,” in which he injected people with malaria, which cause a very high fever. He would allow them to cycle through three or four pikes of malaria fever, then dose them with quinine. Treatment centers sprang up all over the world, including several in the United State.
Talk about a painful cure!
With the advent of penicillin in 1928, malaria was no longer used in the treatment of syphilis. It and many other deadly diseases finally became treatable.