Biting

[mlv]

This age group are oral by nature they bite for many reason. Most people are quick to assume it's out of aggression only. Many child bite as reaction to all emotions even when they are happy or excited. Children will even sometimes bite to show affection. This age group don't yet understand that other people have different feeling as their own. Therefore if it feel good to them they think it must feel good to the other person.
It sounds like she is not doing it out of aggression which is the easiest to step in and prevent.
If this is new behavior and she is teething my guess is that she is looking for relief. You could make sure she has inappropriate things for her to chew on thorough out the day. I find a lot of children like cold when they are teething. I have often rolled up a wet face cloth and put it in the freezer for the children. They seem to really like it for some reason. I would also continue to shadow her and closely observe her, you may be able to pick up on changes in her temperament when she attempts to bite. This could help you know if you need to step in a prevent. I hope this helps, I have dealt with a few biters and know it can be very frustrating.