What are the four exmaples of disease imagery used in Act 4 of Hamlet?

There is disease and decay imagery throughout the play,
but in Act 4 the disease imagery is primarily used by Claudius in his talking about the
problems he is having with Hamlet.  Here are three
examples:

1.  In talking with Gertrude about Hamlet in
scene 1 Claudius says that the people will think that it was their great love of Hamlet
that kept them from keeping him under control or stopping him, and therefore he was a
danger and he killed Polonius.  He compares this to a disease when he says they are
"like the owner of foul disease, to keep from it from divulging, let it feed even on the
pith of life."  They are willing to let the disease (of Hamlet) destroy them rather than
admidt there is problem.

2.  In a short soliloquy at the
start of scene 3 Claudius calls Hamlet a disease and states that, "diseases desparate
grown by desparate appliance are relieved."  He means that the only way to end the
problem of Hamlet is by some desparate means -- he plans to have him killed in England. 
The worse the disease the worse the cure (like cancer and
chemotherapy).

3.  At the end of the scene 3 Claudius again
refers to Hamlet as his disease and says he is "like the hectic in my blood (and) he
rages" and is calling on England to "cure" him.