I took all her cure potions away and sent her against a group of vampires. How can i tell if she has the disease that causes vampirism? Also... since I'm a werewolf, can i make her a werewolf too?

I don't think NPC's interact with the world the same as the PC does, mainly their invincible against contracting diseases. Also, even if you did make Lydia into a werewolf its not like she'll ever use beast form >_> (Heck not even Aela uses it outside of a single quest)

It sounds like you have some wired twilight sh*t going on....

Hmm well I guess thats two mods to make then. First, a spell that transforms the character into a dragon. I mean what good is being dragonborn if you arn't going to turn into a dragon.

Second... make vampires, and werewolves interact with NPCs so that if a vampire feeds that NPC needs to get cured before it turns into a vampire, and same with werewolves.

im almost positive u cant make her a vampire. followers dont sleep like u do.

If you really want Lydia to svck the life out of you, I suggest going the marriage route.

I expect Lydia does sleep.

The NPC's are scripted to certain behavioural patterns however while she can be hit with status effects I'm not sure if she can contract disease.

If she did it would be great for about an hour but as her vampirism progressed the towsnpeople would want to destroy her.

Azrael
The Nord with the Sword

"Elder Scrolls did it before Twilight."

I don't ever recall a vampire falling in love with a werewolf in elder scrolls (but iv only been playing since marrowind) and that's what it sounds like the op is trying to do...

hey-ooooo