On return, famed epidemiologist nurses American's swelling (5)
I believe the answer is:
edema
'american's swelling' is the definition.
'edema' can be an answer for 'swelling' (edema is a kind of swelling). I am not certain of the 'american's' bit.
'on return famed epidemiologist nurses' is the wordplay.
'on return' shows that the letters should be reversed in order.
'nurses' indicates the answer is hidden within the clue (nurse can mean holding closely).
'amede' is hidden within 'famed epidemiologist'.
'amede' backwards is 'EDEMA'.
Can you help me to learn more?
(Other definitions for edema that I've seen before include "American swelling" , "dropsy" .)