Tapanuli Fever

Tapanuli Fever, supposedly in Victorian times known as the Black Formosa Corruption, was a "very rare" condition made up by Owen Harper to describe the symptoms of Marianne Till.

Owen told Marianne that the fever was endemic to a few small regions of South America, including Argentina. He compared it to Ebola. (PROSE: Slow Decay)

Behind the scenes
In the real world, Tapanuli Fever is a creation of Arthur Conan Doyle which appears in the Sherlock Holmes short story The Adventure of the Dying Detective.