A certain female family member comes and stays with us once every couple of months. She has an "odor" from

down below. It is pretty bad, and I don't know what to do. My little boy went to the bathroom this weekend while she was here and when he got to the toilet he said "Ewww! It smells like Aunt "Teresa". I was thankful she didn't hear this, but that smell is over-whelming. She is a very large woman so I don't know if it is an issue of just not being able to clean herself properly, or if it is an infection...I don't know but I need to know how I can tell her in the most polite way that she needs to get this checked out??? I love her very much and I would NEVER want to hurt her feelings, but I just don't know how much longer I am going to be able to take that smell. Please, only considerate, mature answers.