Last mice destroyed in local (7)
I believe the answer is:
endemic
'local' is the definition.
(I've seen this before)
'last mice destroyed in' is the wordplay.
'last' becomes 'end' (I've seen this in another clue).
'destroyed' is an anagram indicator.
'in' means one lot of letters goes inside another.
'mice' is an anagram of 'emic'.
'end' going inside 'emic' is 'ENDEMIC'.
(Other definitions for endemic that I've seen before include "locally confined" , "Prevalent among a group of people, disease perhaps" , "Local (of disease)" , "Widely prevalent" , "Restricted to a certain area" .)