I would also say SHB larvae.
The hive will abscond if you don't do something. If the infestation is bad, I would move the hive off the stand, put a new setup there (bottom board, hive body, new foundation or old comb from storage, the whole shebang). Then I would shake the bees off onto the ground in front of the hive and freeze the comb to kill the eggs and larvae or find a nice healthy fire ant mound, give the mound a little kick and lay the frames on the anthill.
We had an otherwise strong hive last year that appeared to be bursting at the seams, but it turned out the SHB had made a mess of the comb in a matter of days since the previous inspection causing a majority of the bees to hang around outside the hive instead of keeping things in order. We managed to save it in this manner and followed it up with a new queen.