[Name] Progenitor Virus [Source] Resident Evil [Symptoms] 
In the back-story of the series, the Progenitor virus is the primary virus created by the Umbrella Corporation, a mutagen based on ebola, with some of its components extracted from strange flowers that bloom underground, seen in Resident Evil 5. Successor viruses include the T-Virus, the G-Virus, and T-Veronica Virus.