Beset Bumblebee

I noticed this bee on the edge of a marigold vigorously rubbing itself. I took a few shots of it and when I looked at them on my computer screen I saw that it is infested with very small eggs or mites. You can see them at its “waist.” Another shot shows more clusters behind its head and on the inside of the thighs. Poor bumblebee. I wonder how widespread the infestation is.