Circa Seventh Book

Hermione: Has the wizarding world discovered vaccines?

Ron: A wax what?

Hermione: hmmmm

Harry: Hermione, we cant take out the death eaters with a genetically magicked disease

Hermione: No I know that. Of course I know that.

*Uncomfortably long silence*

Harry: What if we gave them all smallpox

Hermione: HARRY NO! We already eradicated it once, let's not make the world do it again

Harry: Oh yeah, I guess you're right

Hermione: Now tuberculosis, on the other hand...

Hermione: If Voldemort likes the good ole' days so much, why don't we bring them back? Old society, old war tricks

Hermione, putting on a gas mask: New plan. We take them out with consumption and mustard gas

Hermione, to Voldemort: Did you know, historically, a majority of war deaths come from disease?

Harry Potter and the Violation of the Geneva Convention