Is Snape a Vampire?

[lake4fam at earthlink.net]

No: HPFGUIDX 26287

  I can think quickly of two vampires who could walk by day:  
Barnabas Collins, due to the medical intervention of his doctor, and 
Francis Ragozcy, Count of Saint-Germain, who lines the soles and 
heels of his boot with Transylvanian earth.  Strong sunlight does 
trouble him, but he does not shrivel up and blow away.
  Severus may have a similar protection that allows him to teach by 
day, and to referee Quidditch matches.  Of course, there are very few 
stray beams of sunlight in a dungeon.  By the way, do we ever see 
Snape eat?  If so, I think this dispells the Snape's a Vampire 
theory.  If not, upon what does he sustain himself?
I cannot imagine that Dumbledore would be willing to hire a teacher 
who would regard the student body as a smogasbord.