According to Adell, her name is Takano Miyo. From what I can gather, she was a nurse back in the world the syndrome originated in.

[The fact that she's seen the final effects of an obsession like this before makes her handwriting just a tad sloppier on the next part.] From what he was telling me, she's apparently fanatical about researching the Hinamizawa Syndrome and is infected as well. As I understood, it's set off her own hallucinations in the past and she's apparently done some particularly extreme things because of it back home.