Place associated with fever epidemic (6)
I believe the answer is:
plague
'epidemic' is the definition.
(I know that plague is a pandemic)
'place associated with fever' is the wordplay.
'place' becomes 'pl' (abbreviation used in postal addresses).
'associated with' means one lot of letters go next to another.
'fever' becomes 'ague' (illness causing fever).
'pl'+'ague'='PLAGUE'
(Other definitions for plague that I've seen before include "Pestilence transmitted by rat fleas" , "Widespread, contagious and destructive disease" , "Epidemic diseases with high mortality" , "Pestilence, scourge" , "Annoy continually" .)