The start of the virus was unknown, but it started and spread through Equestria like wildfire, killing countless thousands of ponies. Hardly any are still alive, and the ones that are struggle to survive. The Mane Six are a few of the survivors, and
Twilight never became an alicorn princess and instead lost her life as a result of Star-Swirl the Bearded's unpredictable spell. But being dead doesn't prevent Twilight from visiting those she cares for...