Spread disease briefly after month, and end of quarantine (9)
I believe the answer is:
marmalade
'spread disease' is the definition.
'marmalade' can be an answer for 'spread' (I've seen this before). I am unsure of the 'disease' bit.
'briefly after month and end of quarantine' is the wordplay.
'briefly' means to remove the last letter.
'after' becomes 'a la' ('a la' - 'in the style of ' or 'after' in French).
'month' becomes 'dec' (abbreviation for December).
'and' is a charade indicator (letters next to each other).
'end of quarantine' becomes 'marm' (I can't justify this - if you can you should give a lot more credence to this answer).
'ala'+'dec'='aladec'
'aladec' with its last letter taken off is 'alade'.
'alade' put after 'marm' is 'MARMALADE'.
Can you help me to learn more?
(Other definitions for marmalade that I've seen before include "Breakfast preserve" , "Orange preserve" , "Spread" , "Kind of cat" , "confiture" .)