Sorry to piss on the collective firework here but...if the DE or whoever already has the disease how come he isn't showing any of the symptoms? That only just occurred to me. Also, if he's sick but not showing yet, how does he know he's going to die, and how will the mediwizards know what the sickness is to cure it? Everyone would need to be quarantined for weeks.
Unless he is dying of something else but got infected with a virulent wizard-only virus *as well*. Was that what we had in mind?
your last sentence was already what i was first thinking.
also, if he's a Durmstrang DE he could be using Illusions to mask his symptoms.
and instead of making his final announcement loudly, he could collapse, coughing up horrible things and with the last of his strength cast a certain symbol into the room.... grab the person who crouched down to help him and yell "This is REVENGE!"
and if the people who were near him when he collapses are the ones to get sick, because he's coughing and other things, or even just the people he was mingling with earlier. it would be very easy for people to say whether they got sick or not.
what if we take an existing disease which mutates somehow and becomes more aggressive? maybe even with different symptoms? that could cause a panic but it's also possible to find a cure.
if he's nutters, he could have been trying to mutate it into something far worse, and thought he succeeded. basically he's convinced its going to cause a country wide wizard plague... and it doesn't.
