@Anitvenomz
Why would diseases from a fantasy world be difficult to figure out?
If the biological life in said fantasy world was equivalent to life in this world, they'd still have similar diseases. Any difficulties she'd have in the fantasy world in identifying illnesses would be no different than identifying them here on earth. The methods of contracting an infection of any kind wouldn't be different, and neither would the environment for the development of bacteria, parasites, or viruses be any different than the real world.
Also, there's been no mention of so called "magic based" diseases, so that rules out some kind of super plague of any kind.