The Accidental Fever

Before antibiotics changed the calculus of medicine, neurosyphilis was a one-way street. Known as general paresis of the insane, it packed 19th- and 20th-century asylums with patients facing inevitable neurological and psychiatric ruin. There was no treatment, no arrest, and no recovery. The condition was uniformly fatal.

Then came a treatment that sounds less like medicine and more like medieval sorcery: deliberately giving patients malaria.

The Austrian psychiatrist Julius Wagner-Jauregg had noticed years earlier that psychiatric patients occasionally experienced remarkable remissions after surviving high-fever infections like erysipelas. Lacking modern pharmaceuticals, he tried various vaccines before hitting on a systematic approach using malaria. In 1917, he began inoculating neurosyphilis patients with Plasmodium vivax, intentionally sparking violent, repetitive fevers.

The logic was brutally simple. The spirochete bacterium responsible for syphilis, Treponema pallidum, is sensitive to heat. By driving the patient's body temperature to dangerous heights, the induced malaria cooked the infection. Once the fevers had done their grim work, doctors administered quinine to kill off the malaria parasite, leaving a significant percentage of patients cured or halted in their decline.

It was a delicate, high-stakes gamble with a lethal parasite, balanced entirely on whether the cure would finish the patient before the disease did. Yet it worked often enough that in 1927, Wagner-Jauregg was awarded the Nobel Prize in Physiology or Medicine, marking the first time the honor was given for a psychiatric or neurological intervention.

Modern bioethicists look back on the practice with profound unease, wrestling with the ethics of deliberately infecting vulnerable psychiatric populations with a deadly disease. But for a brief window before penicillin rendered pyretotherapy obsolete in the 1940s, saving a mind sometimes required setting the body on fire.