One's mood after daughter gets viral disease (9)
I believe the answer is:
distemper
'viral disease' is the definition.
(I've seen this before)
'one's mood after daughter' is the wordplay.
'one's' becomes 'i's' (Roman numeral).
'mood' becomes 'temper' (temper is one's mood or state of mind).
'after' is a charade indicator (letters next to each other).
'daughter' becomes 'd' (genealogical abbreviation).
'is'+'temper'='istemper'
'istemper' after 'd' is 'DISTEMPER'.
'gets' acts as a link.
(Other definitions for distemper that I've seen before include "Disease of animals, especially dogs" , "Water-based paint" , "Canine ailment - whitewash" , "Paint; disease of dogs" , "Viral disease" .)