Corraborating what Finsky says. That is why to kill the brood, there are mites in "them thar hills", hiding, destroying baby bees, to emerge, latch onto an adult and then.......
In my understanding of the mite babies. If you see 1 mite on a bee, you can know that the mites in the cells will be 10-fold of this.
One mite means means 10 in cells. Two mites means 20 mites in cells. Three mites means 30 in cells. These are only approximations, but take it from there, do a little bit of math, and you see how colonies can become over run in no time at all. Mites are serious, and are one of the worst plagues of the bees in these days. Sounds like, "here we go again, time for learning and listening", but yes, here we go again, learning, and learning more. Have a wonderful and greatest of this day on our earth. Cindi