It's awful isn't it? Biting is such a frustrating thing, we've had our share of serial biters at my centre, thing is they are usually sly, you can watch them like a hawk and the second you turn your back to help someone, bang, there they go again.
It's a really difficult thing to deal with in the childcare situation - our hands are tied as to what we can do, Accreditation now has decided that we aren't even permitted to use time out as a behavioural management strategy - so what are we meant to do? It's so upsetting to the child, the child's parents, the staff and most of the time, the biter's parents are horrified too. I know how sick we all feel when the biter has bitten the same child yet again.
I am not by any means dismissing your feelings, you have every right to feel how you do, and yes, the parent of the biter should be informed every single time that the biting occurs. And behvioural mangement strategies developed, but as discussed above, just what they can be is in question.
Most biting occurs in the toddlers group, so by the 2-3 room, I would think this age should be growing out of the behaviours and really understand right from wrong.