Check out this picture: http://3.bp.blogspot.com/-5XdTesoYJx...0/IMG_3082.jpg
It's way too big to post here, but it needs to be because of the detail. This is a picture of the bottom board of a hive I have that last fall had the most profound mite infestation I've ever seen. I've heard of worse, but who can believe the stories? As you may be able to see, there are hundreds of mites on this bottom board.
This is the bottom board I would expect of a hive that died from mites. But this hive is still alive. It just goes to show you never know really how far they can go unless you let them go there. It's the main reason why I let hives die rather than requeen them or try to save them in some way. I'm not tell you that you have to do it this way, but this is the way I do it.
More of the story at my blog. http://parkerfarms.blogspot.com/2012...any-mites.html