Cant sleep

First real exam is tomorrow. I won't be satisfied until I get the answer to this question:

A has a rash and he ignores it thinking it will go away. Turns out it is a rare disease that could be fatal if left untreated. A walks through the hall (unaware of his disease) he unintentionally sneezes on B who happens to have a rare congenital immune disease (wtf?) She is unusually susceptible to viral infections and subsequently contracts A's rare disease which leaves her hospitalized for a month.

Discuss her rights.

Ok, since A was unaware of the disease there is no intent. You see if he was aware he had..say herpes and then had sex with someone he would be intentionally causing harmful contact (battery) Sooooo.....does that mean A was negligent by sneezing on B? He has no duty to her, therefore he didnt breach anything, unless one has a duty to keep their sneezing to themselves (which should be a law) I digress. If he does have a duty then it can be argued that "but for" A sneezing on B she would not have contracted this disease. She was harmed and it was within a reasonably foreseeable scope of risk (proximate cause) Is A liable for negligence?

Isnt B assuming the risk by being in public I mean viral shit is rampent, right? Shouldnt she be in a bubble or something?

I say no but I can't figure out why this is on the hypo if there is no cause of action.