Lycanthropy and vampirism were always regarded and incorporated into the game as diseases, where they are actually more a condition or state.
A condition or state you can pass on by biting or scratching...
I'd agree that Lycanthropy and Vampirism are not normal diseases (they can't be cured by Cure Disease potions, after all), but they can be cured all the same. There's potions, spells, or rituals that can take care of it.
Which is odd since I'm pretty sure lycan means wolf.
Lycos means wolf.
And anthropos means man. Lycos-anthropos is contracted to lycanthrope, which means wolfman. Lycan is a horrible word that the Underworld movies made up to mean werewolves. I guess "lycanthrope" wasn't cool enough or something, and would rather be associated with http://en.wikipedia.org/wiki/Lichen.As far as lycanthrope being used to mean any werecreature, yes, that is an oddity which Daggerfall itself even notes:
Because the werewolf is the most ubiquitous of lycanthropes, the term lycanthropy has been used since ancient days to describe the disease that transforms men into half-beast, although lycanthrope only strictly should refer to men who change into werewolves. But that is semantics.