Toli-X

Toli-X was a mutated virus that spread from planet to planet through asteroid mold, contaminating many worlds around 54 BBY. Although lethal to Humans if untreated, the Toli-X infection could be cured by a vaccine created shortly after the virus appeared. During a mission to Kegan in 44 BBY, Jedi Padawans Siri Tachi and Obi-Wan Kenobi discovered that the the Outer Rim planet had had a severe outbreak of Toli-X seven years prior, but had never learned of the vaccine because of their isolationist government. The parents of V-Davi, a local boy Tachi and Kenobi became acquainted with, had died of the virus when V-Davi was two years old. To save him from unnecessary grief, the Jedi apprentices initially decided not to reveal that a cure against Toli-X had been developed, until they had to use the fact as impetus to help break V-Davi of the brainwashing of the Re-Learning Circle.

The Toli-X virus was first mentioned in The Fight for Truth, a 2000 novel that was the ninth installment in the Jedi Apprentice series of young reader books by Jude Watson.