I saw this movie when I was a child, and I cannot recall the name of the movie, nor too much about it. All I can recall are a few scenes, that I may be embellishing slightly since I saw this movie when I was about 6 years old? Maybe?

Does any of this sound like a movie you know?:

I remember that a son lived with his mother, who appeared to be quite older, perhaps in her late 60s or even older (though, this old age may be attributed to the fact that I was young when I saw this movie). His mother goes on a date with this unknown gentlemen, when the son witnesses his mother and this man eating someone in a back alley. The man, and now his mother, had red eyes and pointed teeth. I also remember that the son would chop up the bodies that his mother ate (she was infect with this 'disease' by the gentlemen) and put them in black garbage bags to dispose of. I remember the ending involved a fire in the house, and the mother was on the floor with her back against the wall, telling her son to leave the house and let her burn because she was a monster.

Does this description ring any bells? I've been trying to discover the name of this movie for quite a few years now, and I'm getting quite desperate as of late to figure it out. Any thoughts are appreciated.