Blood Curses vs Magical Curses and Healing Them

In part because of the Strigoi monster I created (Gypsy name for Vampire), and in discussion about other curses transmitted by bite, I have been chatting with some other DM's about curing survivors of such bites.

Lycanthropes, according to the Monster manual, can have an early intervention of belladonna treatment (which has a chance of killing the PC) to prevent spread of the blood curse.  As someone else once said (Hey there OO) "Lycanthropy is not an STD".  Meaning, it's not just some weird biological disease or something.

Lycanthropy is a "Blood Curse".  Mystical in origin, but not handled as a typical magical curse.  Similarly, vampirisim, by any name, is a blood curse.  Meaning, you don't just cast a spell and someone becomes a Vampire/Strigoi or Lycanthrope.

Consequently, a spell such as "Remove Curse" will not work on a person having been bitten by a Vampire/Strigoi or Lycanthrope.  A magical curse is cast "externally" so to speak and is usually a temporary condition.  "Blood Curses" are permanent and completely life changing.

In my rules regarding Strigoi,  I have it so that only a "Heal" spell by a Cleric or a "Wish" spell will "cure" a living person of a "Blood Curse".  "Heal" is more than a regular "Cure ... Wounds" spell and falls more into the "Miracle" category.  Thus able to remove any blight of the body and soul or otherwise.  It is a transformation of the person, much as a "Blood Curse" transforms a person.

Having said that, once a person has become so "Healed",  I require a System Shock roll because such a drastic level of change can kill a person.The person is being taken from a somewhat magical/mystical condition that would protect them from typical System Shock consequences to a "normal" non mystical condition, thus not protected from the changes that happen as a Strigoi or Lycanthrope.

I have a Flesh Eating Zombie in a similar condition. FEZ's are not created by typical curses or spells.  They are created by mystical disease originating with a person. (No thanks to a Demon Lord named Imdugud/Pazuzu)  Thus once started on it's way with the first person, all subsequent bite victims of FEZ's also become FEZ's and it is essentially a "Blood Curse".  If a "Heal" or "Wish" spell is used befrore the person succumbs to becoming an FEZ they can be spared the transformation.  Once changed, that's it, the best they can hope for is true death.