I straight up use an HMHVV variant that turns people into Howling-esque werewolves. They drain Essence out of newly shredded corpses, they regenerate really fast, and when they transform (either voluntarily or because it's a full moon) they grow into 3.5m tall monsters. The vampire template in Shadowrun works so very well for werewolves that I am honestly offended at the crap we got served up in Paranormal Animals of Europe. Every way they made Loup Garous different from Vampires made them less like Werewolves and made the definition of HMHVV less coherent.
So a lycanthrope transformation looks like this:
1. You're walking along minding your own business, when a big hairy monster leaps through the wall like he's the Koolaid man and rips you to shreds.
2. Said monster takes your carcass off into a tree and eats most of it.
3. Your corpse lies there inert for a few days while the virus takes it over. Your wounds are repaired by the regenerative power of the virus' magic.
4. You rise again as a big hairy monster and go eat something or someone.
5. You wander off, temporarily sated. After a bit you transform into a human form that has most of the memories of the pre-lycanthrope attack human. You wake up naked and covered in blood with nary a mark on you and have no idea what the hell just happened. If you remember the original monstrous attack it is at best a hazy reccollection - like a nightmare.
Right. So much better from a mythological accuracy, epidemiological accuracy, and all-around coolness point of view. Also, this makes for much better shadowruns than "It's a violent guy who bites people!"
-Frank